Category Archives: Blog

An early Christmas gift

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PABU_12202013-35_620 COCDecember 21, 2013

On Friday, December 13, a male painted bunting showed up at one of my feeders.  Whatever vestiges of superstition I might harbor about that particular date should be forever banished by his appearance.  It’s one of the luckiest days for me in recent memory.    One of my most intense hopes for the winter bird season had been just this event.  Others include big flocks of cedar waxwings swarming around the dahoon holly now fruiting in my yard, decent portraits of the sharp-shinned hawk that  periodically strafes my feeders, the  sharp-shinned hawk perched with a just-captured painted bunting grasped in his talons… well, maybe not the last one, though that would be a spectacular image.

I’ve lived in my current home for a little over 5 years, and in that time I’d guess I’ve seen painted buntings here 15-20 times.  They aren’t uncommon birds when they’re in central Florida during  their non-breeding season.   But they are hard to see, particularly considering how spectacularly apparent (seemingly) the adult males are.

Seasonal occurrence and abundance of painted buntings at Emeralda Marsh Conservation Area, Lake Co. FL

Seasonal occurrence and abundance of painted buntings at Emeralda Marsh Conservation Area, Lake Co. FL

In the seven years I did weekly bird censuses at Emeralda Marsh Conservation Area in Lisbon, FL, I saw painted buntings regularly between late July and late April.  During January, on a few occasions I saw 4-6 individuals in one day.

A greenie; a female or immature male painted bunting.

A greenie; a female or immature male painted bunting.

Of those maybe 20 sightings of painted buntings around my house, fewer than half have been adult males.  More common are the “greenies”, the females and immature males that are uniformly citrusy green.  Lovely birds in their own right, but they can’t hold a patch to the males.    Of the fewer than 10 males I’ve seen, more than half were seen within the first year I lived here.   The frequency with which I see both males and females has declined noticeably in the last few years.

The reason is simple – habitat.  Big patches of habitat are better bird attractors than smaller patches.  When I bought my house in 2008, the 50-odd acre tract directly behind it was natural habitat – mostly successional oldfield where a fernery used to be, but also including a small grove of several dozen orange trees.  The oldfield habitat was in the woody invasion stage of succession, dominated by grasses and forbs, but in the process of being colonized by young hardwoods.   I had lots of seral  saplings like black cherry and persimmon scattered in little thickets and copses among the Andropogon-dominated  grassland.  Other ruderal taxa like Passiflora and Sida were abundant in spots.   It was a bird magnet.

The view from my backyard in November 2008.

The view from my backyard in November 2008.

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The view from my backyard in February 2009.

In my first winter here, I had grasshopper sparrows, a pair actually, a bird I had never associated with feeder visiting before; white-crowned sparrows, including a mature adult; vesper sparrows; song sparrows; and numerous indigo and painted buntings in or around my backyard gardens and feeders.

Then progress came.  That 50-odd acre tract is now occupied by Citrus Grove Elementary School (aptly named, at least), and the amount of bird-attracting habitat has plummeted from over 50 acres down to my ¼ acre lot and its densely planted gardens.   The diversity of birds passing through my yard, both as feeder visitors and transient migrants, has followed suit.

One of the first acceptable shots of the male I got. Rather have him off the feeder, but you take what you're given, G.

One of the first acceptable shots of the male I got. Rather have him off the feeder, but you take what you’re given, G.

So seeing a painted bunting these days, especially an adult male, is a miraculous gift to me.  But once I had that gift, greedy bastard that I am, I wanted more.  There’s a progression for the obsessed and deranged birder/photographer – see it well (always the best part), photograph it at even marginal quality if that’s all I can get, and finally, obtain high-quality images.   Success at the first two stages doesn’t guarantee the last will follow – my experience with the buntings is that they can appear and disappear at any time.

Even against a background with matching colors, this bird stands out.

Even against a background with matching colors, this bird stands out.

The paradox of painted buntings is that though not uncommon, they are so infrequently seen, particularly away from feeders.  I see them in the field perhaps 10 times a year, tops, including males and greenies.  But watching them around the feeders reveals why – when they’re not actually feeding, they spend their time in the densest, darkest cover they can find, usually in the very center of shrubberies.  They disappear.    When they do venture into the open, they are quite flighty.  They bolt quickly back to cover at the slightest movement or unexpected noise.

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So their behavior is clearly related to the incredible gaudiness of their plumage – they don’t want to expose themselves unnecessarily to sharp-eyed predators, such as sharpies and Cooper’s hawks.  Which raises a question – why don’t they molt out of this bright breeding plumage during the non-breeding season?

Other members of the genus Passerina, like the indigo bunting, do just that.  The brilliant blue males molt most of their bright blue feathers after breeding, acquiring a female-like dull basic plumage.  They then molt again prior to breeding in the following year, acquiring a new brilliant blue alternate plumage.

Male indigo bunting in alternate plumage. Photographed at Occoquan Bay NWR in Woodbridge, Va.

Male indigo bunting in alternate plumage. Photographed at Occoquan Bay NWR in Woodbridge, Va.

Female indigo bunting, photographed in Lake County.

Male indigo bunting in basic (non-breeding) plumage, photographed in Lake County, FL.

The extreme sexual dimorphism (or more accurately, dichromatism, or differences in coloration) between male and female buntings in the genus Passerina is suggestive of strong sexual selection by females during courtship and mate choice.  Females apparently prefer more brightly colored males, which leads to evolution of more colorful males and increasing divergence between male and female plumage.  Pigmentation in some male birds, especially the yellows, oranges and reds produced by the carotenoid pigments, is derived from feeding on plant materials; more brightly colored males may be more successful foragers.  That’s a quality a female bird looking for some good genes for her offspring can get behind.

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Dichromatism has costs for the males, though.  They are far more conspicuous, and so in many dichromatic species, the males revert to a dully-colored, cryptic basic plumage once the breeding season ends.  Male painted buntings don’t attain their brilliant definitive alternate plumage until they are nearly two years old, which also suggests there are negative consequences associated with the transition between a greenie and a spectacular adult.  So why don’t painted bunting males revert to a cryptic greenie plumage after breeding?

The male with his bitch Coco.

The male with his bitch Coco.

That’s a puzzle for brains bigger than mine.  My challenge right now is to watch these birds as much as possible when I get the chance.  If I’m lucky, that will be all winter long for this particular male, but I’m not optimistic about that.  He’s been around, visiting the feeders at least briefly every day, for 8 days.  And today he came back with his little friend, Coco.   She gonna’ be livin’ here  too.   (Big up to JJ for sharing the Coco clip with me).

Coco.

Coco.

PABU_12212013-33_620 C0C

Bipolar robins

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American robin, Tiger Bay State Forest. The woodland phase.

American robin, Tiger Bay State Forest. The woodland phase.

December 14, 2013

I spent a half hour or so with a small flock of American robins deep in the mesic flatwoods of Bear Swamp Road, in Tiger Bay State Forest last week.  A little bit earlier in the morning I had seen another small flock in a cypress swamp in the nearby Woody Tract.   Aside from a couple of small flyover flocks, this was the first time I’d spent much time watching robins this fall.

If there’s one bird nearly every North American with a functioning brain can identify correctly, the American robin would have to be a good candidate for that honor.  Yet despite their abundance and extreme compatibility with some forms of human-modified landscapes, it’s surprising to me how little I really know about robins.  Especially during their winter residence in Florida.  They can be incredibly abundant and conspicuous at times, yet surprisingly shy and secluded at others.  The winter behavior of robins strikes me as bordering on schizophrenic.

The lawn robin. Northern Virginia.

The lawn robin. Northern Virginia.

My first encounters with robins were probably like those of most people – as breeding birds in suburban habitats.  The sight of a robin running across a well-manicured lawn, stopping, cocking the head to one side as if listening, and then pulling out an earthworm like a strand of spaghetti is iconic for this species.   A pair sometimes nested in a thicket of vines just outside the back door of the house in Virginia where I grew up, and the constant coming and going of both parents bringing food to the insatiable young, then carrying away their feces in nice tidy little membrane-bound spheroids taught me how demanding the work of passerine parents taking care of  nestlings can be.  Spot-breasted fledglings follow their parents across the lawn begging for free food when they are fully capable of taking care of themselves.  Their departure in the fall, and more gratifying, their return in the spring, were highly anticipated events for me as I was just beginning to sync my life to that of the activity patterns of the birds that enthralled me.

Bringing food for the nestlings. Scanned from a slide taken in Northern Virginia.

Bringing food for the nestlings. Scanned from a slide taken in Northern Virginia.

Poop removal detail. She takes the fecal sac directly out of the little bird's bum. Scanned from a slide taken in northern Virginia.

Poop removal detail. She takes the fecal sac directly out of the little bird’s bum. Scanned from a slide taken in northern Virginia.

Recently fledged American robin. Scanned from a slide taken in northern Virginia.

Recently fledged American robin. Scanned from a slide taken in northern Virginia.

It wasn’t until I moved to Florida that I saw the other side of their lifestyle and life history.  The return of the robins is still a signature event in the phenology of Florida birds, but here it occurs in late fall and early winter, as huge flocks of robins move into the state to spend the winter.  It’s their winter behavior that intrigues me most now.   During their stay in Florida, between about October and April, they behave as if they were two different species.

A small winter flock of robins.

A small winter flock of robins.

Though Stevenson and Anderson point out in their essential book The Birdlife of Florida that migration of robins in Florida peaks in October, that seems early to me.  Most years I don’t first see robins until well into November.   In the 7 years I did weekly bird censuses at Emeralda Marsh Conservation Area in Lake County, the earliest I ever saw American robins was the 1st week of November, and I usually didn’t start seeing them in significant numbers until much later, well into December and January.

Seasonal abundance of robins at Emeralda Marsh Conservation Area.

Seasonal abundance of robins at Emeralda Marsh Conservation Area.

Part of the biphasic nature of wintering robins in Florida is their relative inconspicuousness during the first month or two they are here.  I usually see my first robins as small to medium flocks of anywhere from a few to a couple dozen birds, flying in a very determined fashion fairly high.  They are on their way to somewhere.  A few calls from the passing flock often first clue me in to their presence.   I’m especially likely to see these flocks early or late in the day, when the birds are dispersing from or returning to their nightly roosts.  Communal roosting is a big part of the lifestyle of robins, during both the breeding and non-breeding seasons.   Male robins during the breeding season leave their mates at the nest each night and congregate to roost with other hooked-up males.  I’d love to be a fly on the branch at one of those roosts to hear what these hen-pecked cocks have to say about their mates.   During the winter, mixed-sex roosts of American robins can number in the hundreds of thousands.

Feeding on black cherry, Prunus sp.

Feeding on black cherry, Prunus sp.

While in Florida, robins feed heavily on fruits; as much as 90% of their diet in winter can come from fruits of as many as 50 genera of plants.  Their frugivorous behavior may have a lot to do with their markedly variable behavior.

A woodland phase robin in the scrub of Ocala National Forest.

A woodland phase robin in the scrub of Ocala National Forest.

During November and much of December in most years, the occasional flyover flocks and the even less frequently seen feeding flocks are my typical experience of robins.  When I find feeding flocks, they are nearly always in fairly dense, closed-canopy hammock or swamp forest, where the birds are usually pretty quiet and quite easily spooked.  Sometimes they are down on the ground hunting for invertebrates, and sometimes up in the treetops, sometimes in the act  of digesting fruits.  Robins regurgitate the seeds of some of the larger-pitted fruits they eat, and there’s a very stereotyped sequence of behavior leading up to the egestion of a pit, culminating with a lot of convulsive gular movements and the jettisoning of the seed.    My impression of robins during this time of year is much more that of a more typical thrush such as a wood thrush or hermit thrush – fond of deep woods and a bit wary and mysterious.

Yakking up a fruit pit. Renowned frugivorous bird expert Dr. Stewart Skeate was unable to ID the fruit from which this seed came.

Yakking up a fruit pit. Renowned frugivorous bird expert Dr. Stewart Skeate was unable to ID the fruit from which this seed came.

But not too much later, perhaps in late January or February, these big flocks of robins show a remarkable behavioral shift – they go urban.  They appear in large numbers in heavily anthropogenic habitats.  In DeLand, they show up on lawns, in gardens, and in fruiting trees that still retain some of their crop.  And they become dramatically more tolerant of human presence.  On Stetson’s campus and in nearby residential areas they first go after the big inflorescences of sabal palms and a variety of other fruiting trees and shrubs.  Horticultural hollies of various sorts are a favorite, as are the native hollies like dahoon (Ilex cassine) and gallberry (Ilex glabra), for the flocks that choose to remain in natural habitat.

Urban phase American robins and cedar waxwings feeding and drinking together on a Stetson lawn.

Urban phase American robins and cedar waxwings feeding and drinking together on a Stetson lawn.

Often accompanied by large numbers of cedar waxwings, these mass incursions into town and the coincident change in their behavior have to be one of the most spectacular natural history events to regularly occur in urban Florida environs.  Lawns can be covered with flocks of dozens of robins, running every which way while eating inverts and picking up dropped fruits.   Tree species with large fruit crops can be swarmed by flocks of hundreds of birds methodically harvesting a few trees at a time.  Like many flock-feeding frugivorous birds, these aggregations of robins can be swirling maelstroms of activity, with individual birds never staying in one spot for more than a minute or two before moving on to a new branch.    And unlike the standoffish woodland robins of November and December, these urban birds don’t seem to mind being around people that much.

Lawn-feeding robins in DeLand

Lawn-feeding robins in DeLand

Feeding on fallen Sabal palm fruit.

Feeding on fallen Sabal palm fruit.

Particularly during rain-free periods of a few days or more during Florida’s dry season, water can be a limiting commodity for these flocks of robins and waxwings.   On my morning drives to work through lovely old residential neighborhoods along W. Minnesota Ave., during the few weeks when these two species invade the town it’s not unusual for me to see small mixed flocks of robins  and waxwings at nearly every corner puddle that has accumulated from nearby lawn sprinkler systems.   The little dudes sometimes get quite feisty over access to a small pool of water.

Urban phase robin bathing

Urban phase robin bathing

Urban phase robin beefing with the waxwings

Urban phase robin beefing with the waxwings

It’s just a joyous time of year to be in and around DeLand.  Not only are the birds more obvious when in town, but they are also much more vocal and approachable.  Sometimes you see and hear robins and waxwings nearly all day long, everywhere you go in or around town.

In late afternoons during these months, I often see large loose flocks of robins flying to the northeast, presumably converging on some huge roosting aggregation, perhaps somewhere in the forests of Lake Woodruff NWR or Ocala National Forest.   At Emeralda, some mornings I saw continuous strings of robins flying in the same direction, presumably leaving a roost; these flocks sometimes numbered in the thousands.

Yakking a cherry pit

Yakking a cherry pit

And then as winter begins to wind down, almost overnight they seem to disappear.  The pullout of the big wintering flocks occurred in February to March when I was censusing birds at Emeralda.

So the obvious unanswered question for me about the wintering behavior of robins in Florida is this: why the dramatic change in habitat and behavior in mid-late winter?  Does the movement of robins into towns and suburban habitats at that time indicate that they have depleted most of the fruit crop in the woodland habitats, where it would seem that they would rather be?  Seems a bit too simple to me, and I love simple explanations.  And even if that is one of the driving factors, why the huge change in behavior, especially their tolerance of human proximity?

Urban robin looking for some grass among all the pennywort on this Stetson lawn.

Urban robin looking for some grass among all the pennywort on this Stetson lawn.

Even for incredibly common and easily observed birds like robins, it’s stunning how little we really understand about how they live their lives, and why.

I heard a small flock of robins flying over my house just bit earlier today, heading towards that big presumed roost to the north somewhere.  They’re still in the mysterious phase of their Florida sojourn.  What a treat it is to look forward to their upcoming schizoid break, knowing that within a month or two I’ll be able to immerse myself in the presence of the ubiquitous urban robins.

 

The double whammy

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December 5, 2013

Grading exams is like flossing – you have to do it, but it’s rarely enjoyable, and sometimes it’s downright bloody and painful.  When confronted with this miserable job, I seek any relief from the tedium I can find.  So this afternoon with a passel of essay questions to score by tomorrow, I took my tests home to grade at a snail’s pace on my back patio, where I could keep an eye on the bird feeders and gardens.  I’ll take any distraction at all as an excuse to postpone grading for a minute or two.

Common ground dove

Common ground dove

And I saw this bird.  When I first saw this young common ground dove working through the millet seeds in the platform feeder, it’s head and neck moving like the needle on a sewing machine, it seemed totally normal.  When I saw it in greater detail through a telephoto lens, it was clearly not.  It appeared to me at first to be carrying an uncracked sunflower seed in its beak while simultaneously picking at the millet.  Closer inspection revealed that it was abnormal in two ways – both the upper and lower beaks were unusually curved, and perhaps a bit elongated, and the distal portion of both maxilla and mandible each hosted a big nasty wad of smegmaceous-looking material.  Even viewing it through 10x binoculars I couldn’t quite figure out what it was – fungal growth, keratin overgrowth of the beak, a tumor … maybe a bit of each.  But it didn’t seem to have impacted this dove much – it looked to be in decent shape, and its plumage looked reasonably well-preened.

That's some nasty looking stuff growing in there.

That’s some nasty looking stuff growing in there.

Turn to the right. Turn to the right.

Turn to the right. Turn to the right.

It’s quite amazing how birds afflicted with these seemingly severe maladies can continue to function normally.  A bird’s beak is obviously its main feeding implement, but it does so much more.  Birds use their beaks for many of the same functions that mammals perform with their hands.   Grooming and preening, manipulation of objects in their environment, exploratory behaviors, and so on.  A malfunctioning beak system would seem to present insurmountable hurdles to the continued well-being of a bird, but it often isn’t so.

The DeBary thrasher, Hemignathus debaryi

The DeBary thrasher, Hemignathus debaryi

I’ve seen a number of these differently-abled birds visiting my feeders over the years.  There was a brown thrasher that visited for several months when I lived in DeBary who had a bill that reminded me of the bizarre Hawaiian honeycreeper, the akiapolaau (Hemignathus munroi).  Though its beak looks like something designed by a crack team of FSU engineers, it is actually functional in the highly specialized feeding niche of this honeycreeper, which uses the stouter lower mandible to hammer at bark, and the long decurved maxilla to probe cavities.  But for the thrasher it had to function like a normal thrasher beak.  Imagine trying to pick a splinter out of your finger with a pair of tweezers whose points miss each other by a centimeter or two.  But like the doubly-cursed ground dove, the thrasher seemed to be making it work.

The southern blue crossbill

The southern blue crossbill

Last winter a severely deformed blue jay visited my yard and feeders for several months.   Dubbed the blue crossbill, she was able to pick up seeds with no apparent difficulty, but I never saw her holding one between her feet and hammering it with that asymmetrical monstrosity.   I saw this bird being courted by another blue jay during the spring, and I was hopeful that she would return to the feeders with her offspring a bit later in the year.   I haven’t seen her again since spring, though.

Pick up seeds? NFP

Pick up seeds? NFP

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Probably my favorite beak-deformed friend is an American crow who I call L.B.  L.B. was one of the first crows to begin visiting my yard and feeders 5 years ago when I moved to a new house in DeLand.  Along with his mate, he has hung around my neighborhood ever since, though sometimes months pass between sightings.  L.B. stands for Long Beak (I’m one imaginative fucker, no doubt), and he is the only crow I’m able to recognize as an individual among my neighborhood clan.  Every year since L.B. and Notch began visiting my yard they have brought their newly fledged offspring by as part of their extensive education.  Although I’m sometimes able to recognize an individual bird for a period of months due to some feather abnormality or molt, L.B. is the only one of my crow buddies that I always know.  Which is kind of cool.  In my demented mind I feel like I have a long-term relationship with these amazing corvids who grace my yard with their presence (The Gifts of the Crow, as John Marzluff phrased it so eloquently).   But L.B.’s deformity is remarkably minor, and clearly doesn’t impact his survival or fitness in the least.  He’s one fecund dude.

L.B., my corvid friend. Or whatever.

L.B., my corvid friend. Or whatever.

L.B. is easily recognizable, unlike my other home corvids.

L.B. is easily recognizable, unlike my other home corvids.

L.B. and his better half.

L.B. and his better half.

Beak deformities are a phenomenon of great interest to ornithologists these days, for two reasons.  They are increasing dramatically in some areas, and we really don’t have any unambiguous answers, or even attractive hypotheses, as to what is causing them.  The U.S. Geological Survey’s Alaska Science Center has been one of the most active participants in the quest to document and understand this disturbing phenomenon, but they have no clear answers as to the etiology.  What they have shown convincingly is how widespread these deformities are – they are found in around 16% of all Northwestern crows and 7% of the black-capped chickadees in Alaska.   A variety of causative agents have been suggested, including pesticides and other chemical contaminants in the environment, nutritional deficiencies, disease, parasites, and genetic changes.  None of them is clearly supported by the data collected by the USGS researchers, though.

Are deformed bird beaks telling us something about pernicious changes in the environment, like the proverbial canary in the coal mine?  I hope not, but fear so.

Restoring ecosystems, one part at a time

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Sceloporus undulatus, the eastern fence lizard. Members of the genus Sceloporus are fondly called scelops by herpers.

Sceloporus undulatus, the eastern fence lizard. Members of the genus Sceloporus are fondly called scelops by herpers.

November 24, 2013

The outstanding scientific discovery of the twentieth century is not television, or radio, but rather the complexity of the land organism. Only those who know the most about it can appreciate how little we know about it. The last word in ignorance is the man who says of an animal or plant, “What good is it?” If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.

  – Aldo Leopold, The Round River

I found a single eastern fence lizard at Lake Woodruff National Wildlife Refuge last Sunday.  I was doddering around the mix of habitats near the Myacca Parking lot, and noticed the scelop, who had already seen me, perched cryptically against bark in the open pine woods.   It seemed like a sighting worthy of commemorating to me.  Not because I found a scelop, though that by itself is cause for a bit of joy for me.  I don’t see fence lizards all that often, and when I do, it is usually in one of the relatively small number of places I’ve seen them before.   Once established, the populations I’ve had experience with seem pretty stable and predictable between years.

The Myacca sandhills colonizer.

The Myacca sandhills colonizer.

I remember seeing, and catching, my first Sceloporus when I was a kid in Northern Virginia.  I kept it as a “pet” for a few days, but couldn’t find a reliable source of food and let it go.  It was the only scelop I ever saw when I was a kid in Virginia, though I found one reliable population in Prince William Forest Park when I was in grad school there years later.   Lizards were pretty much an exotic mystery to me during my Virginia years.

I first begin seeing fence lizards regularly when I moved to Gainesville for grad school in 1979.   One of the entrances to San Felasco Hammock featured a tract of turkey oak sandhills with a somewhat accessible trail through much of it.  I spent a fair amount of time there in the 80’s, and saw fence lizards regularly.  Always in the same specific locations within this piece of sandhills.   So my impression of fence lizards is they are pretty much stay-at-home beasts, not venturing far from their relatively restricted home ranges.

Finding a single scelop at Woodruff seemed significant to me because of these spatial traits I had intuited.   I’d never seen one in this particular area before, though years ago there was a population located maybe a mile to the south, along one of the fire roads into the mixture of planted pine forest and xeric hammock.  Some big slabs of broken concrete, apparently from an old stock-dipping tank, provided physical shelter and thermal stability for the fence lizards, and I found them there nearly every time I made the hour-long hump down the soft sand fire road to get there.

On the other hand, the single lizard I found on Sunday is apparently a colonizer, a potential co-founder of a new population.  And that’s cool.

The planted pine forest near the Myacca parking lot in 1997.

The planted pine forest near the Myacca parking lot in 1997.

Twenty plus years ago when I first began visiting Woodruff, the area around what is now the Myacca parking lot was mostly even-aged planted slash pine.  It was uniform, lacking in structural diversity, and boring.  Sometime in the last decade, refuge management initiated a management program intended to restore this dense, monotonous pine stand into some semblance of the habitat type that existed there prior to anthropogenic disturbance – sandhills.

Fall in the restored sandhills of Lake Woodruff NWR

Fall in the restored sandhills of Lake Woodruff NWR

For me, that single fence lizard spoke volumes about the success of the sandhills restoration.  In the relatively few years since the stand was severely thinned and then subjected to regular controlled burns, this tract of pines has undergone an amazing transformation.   Vegetation diagnostic of sandhill habitats has begun to return and establish reproducing populations.   Wiregrass, Aristida stricta, one of the defining species of sandhills, is now present throughout and in the process of setting seed.  Ecologist Reed Noss argues persuasively in his splendid book Forgotten Grasslands of the South: Natural History and Conservation that while sandhills is sometimes thought of as a forest community, in reality it is a grassland that happens to feature sparsely scattered trees.   Other sandhill flora is especially evident in the fall, when the yellow and purple composites begin their spectacular flowering displays.   Liatris, Carphephorus, Coreopsis, Helianthus…these genera and more are now regular and conspicuous inhabitants of the diverse ground cover.   The change in visual appeal of this piece of habitat now compared to what it looked like prior to restoration is like the difference between a lump of coal and a sparkling diamond.

Wiregrass (Aristida stricta) is a clump-forming grass that dominates the ground cover of mature sandhills, and requires recurrent fires to flower and set seed.

Wiregrass (Aristida stricta) is a clump-forming grass that dominates the ground cover of mature sandhills, and requires recurrent fires to flower and set seed.

Restoring a habitat to a site where it occurred in the not too distant past is sometimes made a bit easier by the presence of a substantial seed bank remaining from the original inhabitants.  Buried seeds from a variety of sandhill species that once flourished at the Myacca site may have contributed to some of the dramatic recovery and diversification of the flora.  But the lizards had to hoof it here from somewhere else.  And apparently found the restored sandhills to their liking.  Well done, Woodruff land managers and ecologists, well done.

Blazing star (Liatris sp) and Pityopsis blooming in the sandhills restoration plot

Blazing star (Liatris sp) in the sandhills restoration plot

The profound wisdom of Aldo Leopold quoted at the beginning of this piece was simplified and popularized by ecologist Paul Ehrlich in this dictum: “the first rule of intelligent tinkering is to save all the parts”.   I don’t think anyone would ever accuse Homo sapiens of intelligent tinkering with their planet, and indeed we haven’t saved all the parts.   Habitat restoration projects like the one at Woodruff are an admirable way to start putting some of the remaining parts back together in ecologically meaningful ways.

The sandhills restoration project at Woodruff is one facet of a larger effort to restore sandhills habitat throughout the uplands of central Florida, where it was once one of the predominant habitat types.  Outright destruction of habitat converting it to commmercial or agricultural uses, combined with decades of fire suppression, have contributed to a drastic decline in the extent of this characteristic and charismatic Florida plant community.   In the absence of regular (every one-several years) low-level fires, hardwood tree species eventually invade sandhills and replace it with hammock, given enough time.  Foresters at nearby Tiger Bay State Forest have been engaged in similar restoration projects along the Rima Ridge tract in the last several years.   Ambitious and enterprising Volusia County conservationist Steve Strawn is in the process of restoring a large tract of private land, used for decades for pasture and citrus farming, back to sandhills near DeLeon Springs.

Longleaf pines are the anchor species for the developing Volusia Sandhill Ecosystem Teaching Landscape at Stetson University.

Longleaf pines are the anchor species for the developing Volusia Sandhill Ecosystem Teaching Landscape at Stetson University.

Even my home institution is now engaged in sandhills restoration.  Stetson biologist Dr. Cindy Bennington and Gillespie Museum director Dr. Karen Cole are several years into an innovative project converting a former lawn of less than an acre into a sandhills teaching landscape.   No seed bank to help with establishment here – every plant species characteristic of a sandhills ecosystem will have to be reestablished by hand.  This site is so disturbed and modified that rumor has it an in-ground swimming pool is buried there somewhere.   Which makes it all the more impressive that in just a few years since the first plantings, the change in this small piece of land has been striking.   The educational impact on the many students who have contributed to this project and on those who will be exposed to this novel resource will surely surpass the ecological benefits resulting from restoration of this piece of land to its former state.

True success of the colonizing Myacca scelop will have occurred once the little hatchlings like this guy start showing up there.

True success of the colonizing Myacca scelop will have occurred once the little hatchlings like this guy start showing up there.

The jewel in the crown of the teaching landscape could well be colonization of this patch by Sceloporus undulatus.   Doesn’t seem likely, though; the nearest populations are at least several miles away, and the little squamates would have to brave numerous road crossings just to reach the site.   Maybe, someday, I’ll have to give them a little help getting there.

Gray day, brown birds

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November 15, 2013

Mesic flatwoods with a recently cleared swath full of senescent redroot (Lachnanthes caroliana)

Mesic flatwoods with a recently cleared swath full of senescent redroot (Lachnanthes caroliana)

There was a sliver of open sky hinting at a glorious sunrise on the horizon when I left home, but by the time I got to Tiger Bay, no more than fifteen minutes later, it was a memory.  Leaden skies, with no hint of optimism about them.  Skies like these could have come straight from the prose of The Road, Cormac McCarthy’s minor masterpiece.   Well hell, they’re all masterpieces, aren’t they, minor or major.  Who am I to label?  A compelling novel whose main character is a depraved necrophiliac engaging in Davian behavior, including the cave – are you kidding me?  Child of God indeed, coming soon to a theater near you.

So as I drove up the charming brick road leading into the north entrance of Tiger Bay State Forest, I was a bit bummed.  My mellow had been slightly harshed.   No glorious early morning light to be had this morning.  I was questioning whether it would brighten enough for any photography at all. Melanins were to be the theme of the day.  Melanins are the class of pigments that give vertebrates their neutral tones; in the feathers of birds, they span the range from blacks and grays to rusty browns and everything in between.  The skies were seemingly tinged with melanins this morning, and as it turned out, the great majority of birds I saw followed the sky’s lead.

The gray, cool conditions suppressed most insect activity. Even these little bumblebees were moving incredibly slowly as they nectared on these asters.

The gray, cool conditions suppressed most insect activity. Even these little bumblebees were moving incredibly slowly as they nectared on the asters.

At the intersection of Gopher Ridge Road and Dark Entry Road (oooh, spooky!), in the southeast quadrant, there is a stand of maybe a couple hundred acres that was modified several years ago by the foresters at Tiger Bay.  This area, formerly dense young wet flatwoods, had been most notable to me for years because of the large numbers of hooded pitcherplants, Sarracenia minor, that flowered each spring along the roadside ditches and depressions.  It was never particularly remarkable to me for birds until the land managers severely thinned the pines and cleared most of the thick undergrowth.  Now, several years later this stand has the feel of a pine savannah, and is often loaded with great birds, including red-headed woodpeckers, eastern bluebirds, Bachman’s sparrows, northern flickers, and so on.  It’s a wonderful demonstration of the power of effective habitat management.  But this morning it was as empty as McCarthy’s road.   I heard a sedge wren chitting from a dense clump of broomsedge and forbs, but the light was so dismal I didn’t even think about photography.

Dark Entry Road

Dark Entry Road

Further east on Dark Entry, past the savannah, the young flatwoods become denser.   But the foresters have been at work in that section recently as well, thinning and opening up the understory in patches.  At one of these patches, a few acres of cleared land now supporting a successional field, I found a large stand of Sesbaenia vesicaria, a weedy legume that can get 6-8’ tall in good conditions. It’s not too dense a thicket for seeing birds, but provides enough cover that even skulky birds feel secure there.   A bit of chattering told me a house wren was in the thicket, so I began a bit of low-level pishing and playback, using just a chickadee scold call.   Response was slow to develop, but within a couple of minutes I saw a couple of birds moving around the back of the thicket, tending in my direction.  One seemed a bit dark for a house wren, but I didn’t pay it much attention at first. Everything seemed dark this morning.  Eventually it moved to an only semi-obscured perch and I was able to get bins on it.

Lincoln's sparrow.

Lincoln’s sparrow.

Shock.  And delight.  It wasn’t a wren.  It was a Lincoln’s sparrow.  This is a bird I see on very rare occasions.  I had never seen one before I came to Florida, though they pass sparingly through northern Virginia, where I began birding.  I had lived and birded in Florida for over 20 years before I saw my first one here.  It wasn’t until I began doing weekly bird surveys at Emeralda Marsh Conservation Area back in 2000 that I saw my first.  Lincoln’s sparrows were regular, but rare, migrants and winter residents in the wet thickets of Emeralda; I saw them on perhaps 10 occasions there during the 7 years I did censuses.  I had only seen one outside of Emeralda, and that was also at Tiger Bay, in a thicket by the canal that parallels the South Entrance road that takes you to Rattlesnake Pond.   Thickets and nearby water seem to be a common theme to all of those sightings.  Similarly, this morning’s LISP was in the Sesbaenia thicket, which was less than 20 yards away from several small depression ponds.

Lincoln's sparrow

Lincoln’s sparrow

What an elegant little sparrow.  But what a recluse.  That was my experience at Emeralda as well; rarely did I get unobstructed views or photo ops with Lincoln’s.   After thoroughly intoxicating myself with lovely binocular views of this dapper dude, my thoughts turned to shooting it, if only for documentary purposes.  Didn’t seem likely, as he was still way too distant for decent shots, and completely or partially blocked by vegetation about 90% of the time.  Eventually he did give me a couple of distant and brief photo ops, and in the last, he was completely exposed on an open perch surrounded by maidencane.  Not the frame-filling fantasy shots I had visualized (yeah, like those visualized fantasy shots ever happen), but good enough, with massive cropping and consequent low image quality, for decent record shots. I was as happy as a little girl.  The gray morning was now glowing.

Seeing sparrows well, and in particular the less common sparrows, has that effect on me.  Sparrows are tough.  Seeing many of the wintering Florida sparrows clearly or regularly often involves slogging through dense cover to flush them out.   My people don’t do slogging through dense cover well.   Seeing the rarer sparrows is both difficult and exhilarating for me.   One of the high points among my Florida birding experiences was the cold, dank, drizzly January morning that birding legend John Puschock took me to a weedy field near Bull Hammock at Emeralda Marsh Conservation Area and flushed both LeConte’s and Henslow’s sparrows, affording me killer views of both species.  Two lifer sparrows within minutes of each other.  Awesome.

The LeConte's sparrow John Puschock found for me. Scanned from a badly underexposed slide.

The LeConte’s sparrow John Puschock found for me. Scanned from a badly underexposed slide.

So this morning’s Lincoln’s sparrow didn’t quite reach that level of excellence, but it was pretty damned fine. It’s kind of a funny feeling seeing what you know will be the best bird of the day the very first thing.  Kind of a release – no matter what I was to see or not see the rest of the morning, I already had that peak experience under my belt for the day.   And in fact I didn’t see anything else as buzzworthy as the Lincoln’s sparrow, but I saw lots of other cool birds.   Even without the Lincoln’s sparrow, it would have been a totally fulfilling communion, which I should know by now.  It’s always worthwhile going out to look at the real world.

House wren

House wren

Melanin-dominated birds were the order of the day.   Leaving the Dark Entry pine savannah, I found the sedge wren I had heard earlier, along with a buddy.   Light still sucked, but they teased me for quite a few minutes with brief glimpses and ephemeral open perching.  As it turned out, sedge wrens were widespread in Tiger Bay this morning.  I saw or heard them at nearly every stop with appropriate habitat.  Along with their even drabber, browner cousins the house wrens.

Sedge wren

Sedge wren

A bit later, in one of the large clearcut tracts of drier flatwoods on the east portion of Bear Swamp Road, I found more LBJs.   I had taken my Ornithology class to this section of Tiger Bay earlier in the week, and we had found both chipping sparrows and a coquettish song sparrow in the dense successional tangle of the clearcut.  The song sparrow taunted us at great length, moving all around the group while chimping constantly, but giving only the most fragmentary of views.   He was still in the same area this morning, still chimping, and still staying mostly hidden.  A couple of congeners, however, were a bit more obliging. Two swamp sparrows ventured quite close to me, though they never fully came out into the open.   I think swamp sparrows are the most understatedly handsome of our common winter sparrows, but getting clean BOAS-style portrait shots of them is no easy feat.  If that’s what you’re in to.

Swamp sparrow

Swamp sparrow

By now, it was nearing 10 a.m., and the sky was starting to spit.  Work beckoned.  Which might give the erroneous impression that I actually work for a living.   Gray and now damp with declining prospects for the near future.  But what did I care?  The little brown birds had given me all that I could have hoped for and more.

The most colorful bird I photographed this morning. Nonetheless this male common yellowthroat chose a lovely brown background for his portrait.

The most colorful bird I photographed this morning. Nonetheless this male common yellowthroat chose a lovely brown background for his portrait.

Remembering old friends

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Saltbush (Baccharis halimifolia) blooming in the mesic flatwoods of Lake George Conservation Area

Saltbush (Baccharis halimifolia) blooming in the mesic flatwoods of Lake George Conservation Area

November 10, 2013

True fall tends to make me ruminisce (a hybrid mental process involving both reminiscence and rumination), often tending towards the melancholy.  True fall is for me defined by two things:  the point in time when I begin to perceive a significant change in temperature, cross-factored with a decided shift in the bird fauna from the transient migrants towards winter residents.   The indicator event of the latter is for me is the ascendance of the yellow-rumped warblers¸ the fourth wave of migrant warblers, to numerical dominance.  I encountered both those indicators this morning when I cruised Lake George Conservation Area, just west of Seville.  So it’s not surprising that a lot of stuff I experienced today brought back memories.   Most good, some bittersweet.

After a spectacular mackerel sunrise that I was unable to capture on sensor because I failed to follow Skeate’s 6 P’s (prior planning prevents piss-poor performance), I reached the entrance to LGCA at Truck Trail 2 a bit after sunrise.  The spectacular sunrise soon turned to a mostly overcast, dully-colored kind of early morning.   Bird activity was notably lacking at first light.   At my first stop, unproductive for birds, I found a jaundiced-looking lynx spider in a fruiting branch of beautyberry that seemed photoworthy.  As happens nearly every time I do anything related to spiders, I thought of my graduate school friend Craig Hieber, who taught me a significant proportion of what I know about Florida spiders.

Green lynx spider (Peucetia viridans) on American beautyberry (Callicarpa americana)

Green lynx spider (Peucetia viridans) on American beautyberry (Callicarpa americana)

Craig was a great blond bear of a man, with a huge appetite for life and a big, big heart.  He was also a spider fanatic.  We spent many enjoyable hours in the field cross-pollinating each other with inane trivia from our own area of expertise.  I’ll never forget the time Craig hummed to a Neoscona in its web, and by hitting some particular frequency to which that species is attuned, caused the spider to snap immediately into an alert, forelimbs-raised hunting posture. A revelation for me about spider behavior.  Craig died unexpectedly several years ago, far too young.  I remember feeling like I’d been stabbed in the heart when I first learned of his death.  But I remember him and the cool stuff he taught me all the time.  I think it was Alice Sebold who wrote in The Lovely Bones something to the effect that when you have a memory of someone who has died it means that person’s spirit or essence is near you.  If that’s true, Craig spends a lot of time hanging out around me.

Craig Hieber and a nesting soft-shelled turtle we found on one of our outings.

Craig Hieber and a nesting soft-shelled turtle we found on one of our outings.

Neoscona crucifera, the spider Craig sang to.

Neoscona crucifera, the spider Craig sang to.

The other old friends that I remembered this morning didn’t bring such a mixed bag of feelings.  They were mostly the winter resident birds that have recently begun to dominate the avifauna.  I love seeing transient migrants simply because of their evanescence.  My encounters with the transients are too brief to feel like I really grok them though.  With the winter birds, it’s different.  They are around for a good four to five months.  I get to see them and interact with them over and over again during their winter stay.  And for some of the more common ones, I get more of a visceral feel for what they are and what they do. Whatever the hell that means.

Ruby-crowned kinglet, one of the winter residents that defines the onset of true fall.

Ruby-crowned kinglet, one of the winter residents that defines the onset of true fall.

Yellow-rumped warblers were the most abundant passerines of the morning.  One flock contained several dozen birds.  They just continued to drop out of the skies.  As is typical of my experience with the butterbutts, they are dedicated mobbers, but relatively shy and skittish compared to most other mobbing warblers.  In the large flock, not a one came down from the treetops.  When the occasional bird does approach more closely, the slightest movement is all it takes to send the lot of them scattering for cover.  Still, it’s just very cool to see flocks containing that many passerines again.  One of the things I really like about the winter bird fauna.

Every afternoon from about this time of fall until spring migration, the yellow-rumps move through my yard about an hour or so before sunset.  Flocks of anywhere from a half-dozen to 30 or more will appear from nowhere and glean the oaks and cherries in my yard.  They usually stay a half-hour or so, then move on.  Regular as clockwork.  Where are they coming from, and where are they heading to roost?   They clearly have a schedule to keep.

Yellow-bellied sapsuckers are another winter friend I love seeing again each fall.  I had seen a few sapsuckers in the previous couple of weeks with the Ornithology class, but hadn’t got a chance to watch one at length before this morning.   I don’t think I can say I really grok sapsuckers yet, but I’m getting closer.  Such a recluse, for a woodpecker.  Maybe that’s one of reasons I like them so much – the whole birds of a feather thing.   All of our other woodpeckers are pretty good at making a dramatic entrance when they want to – a big power glide and swoop onto an open trunk is pretty hard to miss.  Sapsuckers may be able to do that, but they don’t seem to want to very often.  They just kind of slip in quietly most of the time, and all of a sudden they are there.   And disappear just as quickly.   Their presence is better judged by their works.  In some habitats, sapsucker drill holes are everywhere.

Yellow-bellied sapsucker at Lake George Conservation Area.

Yellow-bellied sapsucker at Lake George Conservation Area.

Can plants be friends? Hell yes they can.  As the great Zappa once wrote, “Call any vegetable, call it by name. Call one today, when you get off the train.  Call any vegetable, and the chances are good  That the vegetable will respond to you”.   So I was thrilled to see big lavender swaths of my old friend Garberia in the flatwoods this morning.  I think of Garberia as a scrub plant, but there they were in the flatwoods looking happy as clams.   Not only is Garberia a lovely plant as judged by the standards of the pure botanist, it is notable for other less obvious reasons.  It’s a very non-composite-like composite to me, which is especially welcome at this time of year when composites of all kinds are going nuts.  Garberia seems to me to be a composite that would really rather be an ericad.   So it has that going for it, which is nice.

Syrphid fly partaking of the pleasures of the botanical hussy Garberia heterophylla

Syrphid fly partaking of the pleasures of the botanical hussy Garberia heterophylla

But it’s also something of a whore for pollinators.  Anybody will do, it seems.  I have, of course, fallen victim to one of the classic blunders, the most famous of which is “never get involved in a land war in Asia”, but only slightly less well known is never make the assumption that all insects visiting a flower are pollinators.  Still, given the relatively open flower morphology and the long easily accessible stamens and style, it doesn’t seem like total heresy to suggest that most of the flies, bees, wasps, skippers and other butterflies swarming over these lush Garberia flowers might effect pollination to some degree.

Buckeye at Garberia. Lake George Conservation Area

Buckeye at Garberia. Lake George Conservation Area

Skipper at Garberia. This was one of the happier skippers I saw visiting the flowers.

Skipper at Garberia. This was one of the happier skippers I saw visiting the flowers.

The highlight of the activity at the Garberia patch was provided by another old friend, a Carolina anole.  This one was creeping around the foliage below the big flower heads, his pie-hole crammed with a skipper he had recently snagged from above.  The stink eye he was giving me as he tried to figure out what to do with his mouthful of chitin suggested that his thoughts towards me weren’t as fraternal as mine towards him.  At least at that moment.

Green anole (Anolis carolinensis) scarfing one of the less happy skippers I saw at Garberia.

Green anole (Anolis carolinensis) scarfing one of the less happy skippers I saw at Garberia.

On playback and ethical bird photography

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October 20, 2013

Most avid and responsible birders and bird photographers have two sometimes conflicting goals:  1) to see (and photograph) as many cool birds as possible, and 2) to minimize any harmful impacts that the pursuit of their goals might have on their subjects.

Although this gray catbird was attracted initially by mobbing call playback, he decided to have a bite while checking out the commotion.

Although this gray catbird was attracted initially by mobbing call playback, he decided to have a bite while checking out the commotion.

Among bird aficionados, there has been a long-running and sometimes acrimonious squabble over the impact of using recorded vocalizations (playback) to attract birds for viewing and photography.  I’ve been using playback in various forms for more decades than I’d really care to tally up.   Given that I consider myself an ethical birder, obviously I have strongly-held feelings about this issue.   The crux of the controversy is whether the use of playback to attract birds, for whatever reason, has any significant negative impact on the birds being attracted.  The standard argument against use of playback is that it might cause birds to expend limited time and energy resources responding to recordings, which in turn  could reduce their ability to deal with more pressing biological needs, such as feeding, finding a mate, or taking care of offspring.  Phrased from an evolutionary perspective, the question is does playback somehow reduce the fitness (lifetime reproductive success) of the birds that respond?  If so, it is a legitimate cause for concern, and perhaps even regulation and restriction of playback by birders.  Unfortunately, there is no hard empirical evidence that this is the case from any properly executed scientific study.  Both sides rely nearly exclusively on anecdote to make their case.

I used playback to entice this yellow-breasted chat into the open for photographs a couple of years ago. This bird gave me about 5 seconds of exposure before he lost interest and went back to what he had been doing.

I used territorial playback to entice this yellow-breasted chat into the open for photographs a couple of years ago. This bird gave me about 5 seconds of exposure before he lost interest and went back to what he had been doing.

The debate received an injection of hard evidence last week.  Three ornithologists published a peer-reviewed paper in the on-line journal PLOS One reporting the results of a rigorous study on two species of Ecuadorian birds (Rufous Antpittas, Grallaria rufula, and Plain-tailed Wrens, Thryothorus euophrys) and their short-term response to playback of species-specific vocalizations.   This study has been widely reported (and misreported) in the popular scientific press.  Here’s the main finding of the study extracted by the popular science writers at ScienceDaily, a respected and generally accurate website: the study “shows that playbacks do have potentially negative consequences, especially in terms of birds’ energies.”

Carolina wren, Thyothorus ludovicianus, a close relative of the Plain-tailed Wren studied in teh PLOS One paper. Carolina wrens are strong responders to mobbing and territorial playback; they are one of the "ringleader species" in many mobbing flocks.

Carolina wren, Thyothorus ludovicianus, a close relative of the Plain-tailed Wren studied in the PLOS One paper. Carolina wrens are strong responders to mobbing and territorial playback; they are one of the “ringleader species” in many mobbing flocks.

The problem I have with reporting this as a major finding of the study is that it just ain’t so.  The data reported in the study provide no evidence whatsoever for negative impacts of playback on these two tropical bird species.  There are no data presented here (or anywhere, as far as I know) dealing with the energetics (and their adverse consequences) of response to playback.   That is pure, unadulterated speculation, without even ancillary evidence presented to support such extrapolation.

Do birds have to abandon other necessary activities to respond to playback? Not this titmouse, who snagged a big juicy puss-moth caterpillar (Megalopyge sp.) while looking for the predator that wasn't there.

Do birds have to abandon other necessary activities to respond to playback? Not this titmouse, who snagged a big juicy puss-moth caterpillar (Megalopyge sp.) while looking for the predator that wasn’t there.

What the Ecuadorian study did show, quite convincingly, is that these two bird species are attracted by playback, and they alter their vocal behavior by singing and calling more frequently after playback.  Well, that’s a real shocking conclusion.  Birds do respond to playback.  Who knew?  Only millions of researchers, birders, and bird photographers who have used playback since recording and playback equipment made such manipulation of bird behavior possible.   It’s why we do it.   However, the PLOS One study provides no data WHATSOEVER that this change in behavior has any adverse consequences to the birds.  In fact, what their data show for the wrens is that repeated playback to the same birds over a 12-day period resulted in a precipitous decline in response.  In behavioral jargon, the birds habituated to the stimulus and pretty much stopped responding to playback entirely.   They learned.   Birds, as it turns out, are quite good at learning.  In the authors’ own words in their last paragraph, they state “This result suggests that playback could negatively affect species if they become stressed, expend energy, or take time away from other activities to respond to playback.  By contrast, the habituation results we present suggest that frequent birdwatchers’ playback may have minimal impacts on wren behavior”.

An ovenbird lured to an open perch by mobbing call playback. This bird doesn't look stressed or frightened to me - it is intensely curious. I think he's digging the moment.

An ovenbird lured to an open perch by mobbing call playback. This bird doesn’t look stressed or frightened to me – it is intensely curious. I think he’s digging the moment.

In other words, their study doesn’t really allow any conclusions at all about the long-term effects of playback on these species, but what data they do have actually support the idea that it’s negligible.  To conduct such a study looking for a long-term effect of exposure to playback and document any effects it might have on mating success or overall reproductive fitness is an order of magnitude or two more difficult than documenting a short-term response to playback.  More studies like the PLOS One study need to be done, but let’s not kid ourselves that they really tell us anything meaningful about long-term impacts.  They show that birds do respond to playback.  No Nobel Prize to be had for quantifying that, though.

In fact, one pair of wrens in the study built a nest 10’ away from the playback speaker.   As anecdotal evidence goes, that’s a pretty strong piece of information supporting the minimal impact interpretation. Other published studies on other species have even suggested a positive effect in some cases.   A study of Black-capped Vireos, a rare, local, and highly-sought species by birders, showed that repeated playback of vireo song in an area actually attracted more vireos to that site, and some of these birds nested in the area to which they were attracted and increased the local population.   Negative impacts of playback?  I’m not seeing it.  Which is not to say that it can’t or doesn’t occur; there simply isn’t any hard scientific evidence to support it.

The Lake George summer tanager on my first visit in April.

The Lake George summer tanager on my first visit in April. This is the tanager who graced me with his very near presence and a brief conversation. If only I knew what he really meant by “pituck”.

But anecdotal evidence?  Everybody has anecdotal evidence.  I’ll share some of mine.  On April 14 of this year I found a territorial male summer tanager in Lake George State Forest, and he responded strongly to playback by close approach  and  repeated flyovers to and from nearby perches.  Not all individuals respond this strongly; my wild-ass guess across species is that maybe only one out of every 5-10 territorial males to which I broadcast recorded vocalizations actually responds by approaching and singing back.  Most often I use playback from my car, which acts as a blind of sorts as long as I minimize any sudden movements.  This particular male actually landed on the window of my car, perhaps a foot away from my head, perched there for about 5 seconds, looked me straight in the eye and said “pituck”.  He then turned and flew back to a nearby perch.  It blew my freaking mind.  I was in a state of extreme elation for the next hour or two.  Being that close to a wild bird who is that close to me of its own volition is an intense and exhilarating experience, which I’ve experienced on a few other occasions when using playback.  How was it for the bird?   As I slowly drove away, I saw and heard him resume his circuit of singing perches he had been using before I began playback.  For all I know, that bird was, in his own mind, one bad-ass mofo.  He had confronted and repelled a bizarre and gigantic territorial interloper.

On my second encounter with this male, not only did he have a female following him, but he also caught several insects while he was responding to playback.

On my second encounter with this male, not only did he have a female following him, but he also caught several insects while he was responding to playback.

Fast forward to June 23, when I returned to that location with my buddy John Serrao.  John was jazzed about the idea of seeing and photographing a male summer tanager at close range.  I was a bit dubious about the likelihood of a strong response; it was much later in the nesting season, and in my experience, the most intense responses to territorial song occur early in the nesting cycle when the males have just established territory and are seeking a mate, and are intent on keeping other scumbag males away from their mate.  Nonetheless, when we heard a male summer tanager singing in the area (almost certainly the same bird I’d worked over a month earlier), we tried playback.  BAM.  He was all over us like stupid on a Tea Partier.  With one important distinction – this time he was being followed around by a female who seemed to be supporting his territorial defense.   As I did earlier, we worked that bird for perhaps 5-10 minutes and left.  Once again he resumed patrol of his territory and his habitual song perches as we drove away.

Summer tanager female who responded with her mate on my second encounter.

Summer tanager female who responded with her mate on my second encounter.

My conclusion from these encounters?  The earlier bout of playback had no effect on the ability of this male to defend his territory and obtain a mate.  Some research has shown that playback to territorial males can increase their serum testosterone levels, which typically show a huge spike during the breeding season for many male birds.  In all likelihood, that results in an increase in the perceived dominance status of that particular bird, and may actually increase their ability to defend a territory and attract a mate.   Egregious speculation?  Maybe.  But that seems to be the standard of evidence in the debate over playback and the ethics of using it to attract birds.

Here’s another side of the playback debate that’s rarely (like never) addressed: there is more than one type of playback, and more than one type of response.  Conclusions drawn from studies on one class of playback response are probably completely inapplicable to other categories of response.

The category of playback most opponents focus on is species-specific playback of territorial song to breeding birds.  Male birds of some territorial species (but by no means all) do respond strongly to such playback, and in some instances, an individual bird will continue to respond over a prolonged period (hours? Again, no empirical studies that I know of).   If an individual male is repeatedly subjected to territorial playback, it’s not hard to imagine that other critical activities of that male might be reduced due to overstimulation.  I’d like to think that anyone using playback would do so with some modicum of restraint and common sense, but I know there are jackass birders, just as there are dillweeds in every other human pursuit.

House wrens seem to have a rollicking good time while scolding a potential predator.

House wrens seem to have a rollicking good time while scolding a potential predator.

I restrict playback of territorial song to any individual male to no more than 10 minutes, and don’t work that bird again for at least several weeks.  In the vast majority of playback episodes I perform, it is a one-shot deal for that particular bird.  I never use playback in heavily visited areas or when other birders are nearby.  I do almost all of my birding and photography in sites that are not birding hotspots.  Often I see only a handful of other people on any particular birding trip, and most of those people usually aren’t birders.  Obviously, birders visiting heavily-visited areas or seeking to find well-publicized rare birds should exercise a high level of restraint in the use of playback.  But they don’t always do so.  News flash:  some people are dicks, be they birders or not.

The other distinct category of playback, which I use far more frequently, is the use of owl calls (screech owl quavers in particular) and alarm calls, scolds, buzzes and chips that are used by birds engaged in an amazing behavior called mobbing.  While territorial playback is generally restricted to a fairly short window of time during the breeding season, elicited mobbing responses can occur throughout the year.

Many birds respond poorly or not at all to playback most of the time. No playback was used in making this shot of a bald eagle at sunrise/moonset.

Many birds respond poorly or not at all to playback most of the time. No playback was used in making this shot of a bald eagle at sunrise/moonset.

And the behavior is a completely different beast than territorial behavior.  Mobbing is a contagious, multi-species affair – the more the merrier.  The strongest responses are evoked from mixed-species flocks containing a half-dozen or more species, often including titmice, chickadees, wrens, warblers, vireos, and a wide variety of other passerines (and some non-passerines, including woodpeckers and hummingbirds – hummingbirds are particularly fearless when responding to mobbing playback).  These birds will travel hundreds of yards (sometimes) to seek out the apparent predator, for reasons and benefits that are not well understood (and certainly not empirically quantified).  While engaged in mobbing behavior, these birds are vocal, active and highly excited.

Is responding to mobbing playback harmful to birds?  No studies address this point at all.  From a methodological and logistical perspective, that would be a very difficult study to carry out.  But I think it’s unlikely to have any significant effects.

Blue-gray gnatcatchers are among the most enthusiastic mobbers. Little dudes have no fear. I had one fly into my car once while looking for a predator.

Blue-gray gnatcatchers are among the most enthusiastic mobbers. Little dudes have no fear. I had one fly into my car once while looking for a predator.

Mobbing response to playback is an extremely transient behavior.  When the birds do respond (and often they don’t), they sometimes approach quickly and engage in frenetic activity and vocalizations for a few minutes. After 5-10 minutes of seeking and failing to find the predator, they shut it down and leave, returning to what they were doing before.  You can’t re-attract those birds by mobbing playback, at least in the short term.  It seems to be a very rapidly-occurring form of habituation, which then shuts off the response for some undetermined period of time.  The nature of the behavior itself limits its potential impact on the individuals that respond.

Cold, rainy conditions severely suppress mobbing behavior. Birds only mob when their other more immediate biological needs are taken care of.

Cold, rainy conditions severely suppress mobbing behavior. Birds only mob when their other more immediate biological needs are taken care of.

And often they don’t respond.  Cold, windy conditions tend to suppress mobbing response almost entirely.  During the breeding season, when mobbing species are defending territory and taking care of mates and offspring, it’s hard to elicit any response at all.  There is huge variability, both seasonally and on a shorter-term basis, to the strength of response.  My interpretation of this variability is that mobbing is a low-priority behavior, with little immediate benefit, that is frequently abandoned when other biological needs (feeding, territorial defense, breeding activities) take precedence.

Am I “stressing” these birds out by attracting them with mobbing playback?  I’d argue emphatically that I’m not.  Even superficial observation of the behavior of mobbing birds tells me that they aren’t frightened by the predator or otherwise stressed out.  In contrast, my HIGHLY subjective interpretation of the behavior of mobbing birds is this:  they love that shit.  I think it’s an exciting, rewarding behavior for the birds that do it, and it provides some internal neurochemical reinforcement making it a highly enjoyable activity.   I think it’s something like an adrenaline rush for these birds.  Sometimes I can almost hear what they are vocalizing in a Dr. Dolittle-type fashion: “Oh boy oh boy, we’re going to kick some predators’ ass!”.  How’s that for egregious speculation?

Playback works poorly for attracting snakes. No ears.

Playback works poorly for attracting snakes. No ears.

One last point about the use of playback: as an educator, I can’t imagine teaching my Ornithology classes without using playback to enhance the birding experience of the students.  Earlier this week while on one of our biweekly field trips, I placed the speaker and Ipod (with several custom-made mobbing vocalization tracks installed) at the base of a clump of winged sumac, and for the next five-ten minutes, the students and I were treated to a progression of very cool birds that came down to check out the jam.   We got crippling looks at cardinals, Carolina and house wrens, a pine warbler, a common yellowthroat, gray catbirds, and a couple of white-eyed vireos, all of which perched briefly in the open as they scoured the sumac, while the class enjoyed the antics of these birds from 15’ away.  When they began to drift away, as they ALWAYS do within 10 minutes or so, I turned off the mobbing track and all those birds resumed their prior activities.  No harm, no foul.  But a handful of budding bird-lovers got looks at those birds that they would never get otherwise.

Obtaining good unobstructed views of skulky birds like this white-eyed vireo can be very difficult without playback, particularly for a group of inexperienced birders.

Obtaining good unobstructed views of skulky birds like this white-eyed vireo can be very difficult without playback, particularly for a group of inexperienced birders.

Did we alter the birds’ behavior by eliciting a mobbing response?  No doubt we did.  Was it harmful?  Hard for me to envision how.  The birds wouldn’t have responded if they had other more critical needs to attend to.   Birders alter the behavior of their subjects all the time.  They frequently cause birds to retreat to cover just by their presence.   Most birders that I have known use the technique called “pishing” or “squeaking” to attract birds or draw them out of cover.  These techniques involve making shushing noises or other sounds that mimic the mobbing calls used by a wide variety of birds to provoke a mobbing response, or at least an investigatory response, by the birds they would like to see better.  They elicit exactly the same response that is provoked by playback of recorded owl vocalizations or mobbing calls using electronic playback.  Any birder who uses pishing but who is also opposed to the use of screech owl/mobbing playback to attract birds is a hypocrite.

Many (most?) birders use pishing or squeaking noises, which imitate mobbing or alarm calls, to get shy or secretive birds like this sedge wren to pop up and take a quick looksee.

Many (most?) birders use pishing or squeaking noises, which imitate mobbing or alarm calls, to get shy or secretive birds like this sedge wren to pop up and take a quick looksee.

Here’s an anecdotal and apocryphal birding tale (urban legend?) I’ve heard many times over the years regarding the impact of hard-core birders on their quarry.   As the story goes, a guided group of birders was visiting some marsh habitat in the northeast in search of the secretive and rare black rail, which had previously been reported from this site.  They assembled at the field site before dawn, and blindly trudged through the muck of the marsh in the dark to get to the site where the rail had last been seen. As the morning light came up after a period of unsuccessful listening for the bird, someone finally spotted it.  Trampled to death in the mud by members of the birding party.  True story?  Probably not.  But it emphasizes the point that we modify nature and alter the behavior, and perhaps sometimes the fitness, of our subjects nearly every time we go into the field.  All we can do is try to be aware of the potential harms, and try to minimize our impact.

Use of playback can sometimes have dire consequences. This northern parula was so excited at the prospect of kicking some predator's ass that he twisted his own head clean off. It was a sad sight to see.

Use of playback can sometimes have dire consequences. This northern parula was so excited at the prospect of kicking some predator’s ass that he twisted his own head clean off. It was a sad sight to see.

Bottom line: is playback harmful?   It COULD be, under specific conditions, although we don’t really have any hard evidence about what exactly those conditions are.   It’s pretty easy, however, for ethical, knowledgeable birders to anticipate many of those conditions and avoid them.  Personally, I have no qualms at all about using playback in the way I do.  I sleep like a baby after a day in the field of playback.

Color pattern conundrums

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October 13, 2013

I had tempered hopes for finding new and interesting migrants when I left home before sunrise Friday morning.   Fall break, a whopping two days, allowed me to forget about classes and go anywhere I desired.

I do most of my birding and natural historizing inland, at sites relatively close to DeLand.   Coastal sites, both on the Atlantic and Gulf coasts, routinely produce higher diversity and abundance of neotropical migrants than do inland sites, but I always feel a little guilty burning gas for longer road trips when cool stuff is surely nearby.   The superiority of coastal sites isn’t surprising given that many of the migrants I’m most interested in follow migratory paths that take them out over open ocean or gulf, and come to land when forced down by storm fronts or local weather systems that  forestall their long-range movements.  So they tend to concentrate along the coasts until conditions improve, during which time they can replenish their fat reserves for the long flight to come.  If conditions are good, many migrants bypass Florida entirely en route to the tropics.

Female American redstart. Tomoka State Park

Female American redstart. Tomoka State Park

Tomoka  State Park was my primary destination, where veteran bird-bander Meret Wilson had reported some great birds in the preceding week (including a Swainson’s warbler, which would be a lifer for me).   I had misgivings though, as Friday morning followed two nights in a row of clear skies, which tend to favor departure of migrants that have been delayed along the coast.  That apparently was the case on this Friday morning, as Tomoka was mostly devoid of anything other than resident species like northern cardinals and Carolina wrens.  One small flock that included an American redstart, a yellow-throated warbler and a couple of prairie warblers contained the only migrant passerines I found there.

Balduina angustifolia, or Coastalplain Honeycombhead. Heart Island Conservation Area

Balduina angustifolia, or Coastalplain Honeycombhead. Heart Island Conservation Area

Palafoxia integrifolia, or Coastalplain Palafox. Heart Island Conservation Area

Palafoxia integrifolia, or Coastalplain Palafox. Heart Island Conservation Area

The great thing about natural history and biotic diversity, though, is that there is always something cool going on somewhere.  So mid-morning found me back inland, at Heart Island Conservation Area.  This was the SR11 entrance to Heart Island, just a bit north of the intersection of SR40 and SR11.  The mostly flatwood habitats there were full of fall composites attracting a diversity of nectaring butterflies.  The flora included several of the purple-flowered species, including  Carphephorus corymbosum, a couple of species of blazing star (Liatris spp.), big gorgeous patches of Balduina angustifolia, and a species of Palafoxia I hadn’t seen before.  The biggest attractor for butterflies on Friday morning were the big white-topped asters (Sericocarpus tortifolius;  thanks, CB), some of which produced flowering spikes over six feet tall.  They were buzzing with activity from both butterflies and bees.

Palamedes swallowtail (Papilio palamedes) at Carphephorus corymbosum. Heart Island Conservation Area

Palamedes swallowtail (Papilio palamedes) at Carphephorus corymbosum. Heart Island Conservation Area

Grass skipper (species undetermined) at Balduina angustifolia. Heart Island Conservation Area

Grass skipper (species undetermined) at Balduina angustifolia. Heart Island Conservation Area

Butterflies visiting these big composites spanned a huge range in size, from small drab orange skippers to gargantuan tiger swallowtails.   There were also several viceroys at one of the clusters, indicating that there were willows nearby.   Viceroy larvae feed mainly on willows, and the adults don’t seem to wander far from the vicinity of their larval foodplants.   The most exciting lep, to me, nectaring  at the Sericocarpus was a single great purple hairstreak (Atlides halesus), a species that I just photographed for the first time a couple of months earlier.   Hairstreaks are among the smallest of the butterflies, but great purples are giants amongst their confamilials.   And this one was not only in pristine condition, but was very deliberate in his foraging movements, repeatedly visiting the same flower clusters and working slowly from one disc flower to the next.  I spent more than a half-hour tracking this one individual, waiting for him to move close enough to me and position himself appropriately for photos.

Tiger swallowtail female at Sericocarpus. Females have extensive blue on the hindwing, lacking males. Heart Island Conservation Area

Tiger swallowtail female at Sericocarpus. Females have extensive blue on the hindwing, lacking in males. Heart Island Conservation Area

While watching and waiting for this one butterfly, I found myself wondering about his spectacular color patterns, and what functions they might serve.  How had natural selection favored the evolution of such a delicate piece of living jewelry?

Great purple hairstreak at Sericocarpus

Great purple hairstreak at Sericocarpus

Brilliant colors and striking contrast are two of the components of pattern in both butterflies and birds that attract so much attention and admiration from naturalists, yet it struck me that we understand relatively little about how these patterns are actually adaptive, beyond a few simple generalizations.

Hairstreaks, for example, are usually instantly recognizable by the adornments of the hindwings.  Most have a pair of thin tendrils extending from the back of the hindwing, and the hindwing is often marked on the underside with spots of color that look something like eyes.  When perched, most hairstreaks habitually rub their hindwings back and forth across each other slowly, while movements by the rest of the insect are slight and barely noticeable.  The adaptive function of the tendrils, spots and movement seem to be to mimic a head and antennae, which presumably misleads potential predators into directing their attack to the hindwings.  It’s not uncommon to see hairstreaks with symmetrical chunks removed from both hindwings, indicating that a predator wannabe fell for the ruse and got nothing but a mouth or beak full of chitin and scales.  The hairstreak survives the attack only a little the worse for the encounter.

This gray hairstreak shows apparent predator damage to the rear of its hindwings.

This gray hairstreak shows apparent predator damage to the rear of its hindwings, suggesting that the tendrils and eyespots there enticed the predator away from the head.

So I get that part.  But what about the other pattern components that are so conspicuous, such as the patches of lime-green scales on the hindwings, and the brightly bicolored orange-blue abdomen?   As much as I love all things Gator-related, that seems unlikely, although there are also some very cryptic grasshoppers that have brilliant contrasting orange and blue patches on the inside of their hindlegs, visible only briefly and sporadically, that must have some kind of signaling function.  Why orange and blue?

Great purple hairstreak. Heart Island Conservation Area

Great purple hairstreak. Heart Island Conservation Area

And then there’s the southern aspect of a great purple hairstreak traveling north.  Not only do they have the wispy tendrils and eyespots on the hindwings – they also have flanges extending from the rear margin of the wings that produce a remarkably face-like visage as the butterfly is walking away.  What is that supposed to look like?  I’m hard-pressed to ascribe a resemblance to any insect I can think of, but it seems likely to me that this is also a feature favored by natural selection somehow, perhaps because of some protective function.

Great purple hairstreak from behind. Heart Island Conservation Area

Great purple hairstreak from behind.  What kind of face do you see?  Heart Island Conservation Area

The swallowtails represent an entirely different suite of characteristics, but are similar in some respects to the hairstreaks.  Big, conspicuous, almost constantly in motion, brightly colored – the overall effect of the swallowtail motif can’t be concealment.   A couple of the tiger stripes, however, converge towards the abdomen, and in many swallowtails there are conspicuously colored spots just below the convergence of these stripes that could function as eyespot mimics.   The tails of swallowtails may serve a similar function to the tendrils of hairstreaks, attracting the attention of predators towards these disposable and dispensable wing pieces.

Male tiger swallowtail at Sericocarpus. Heart Island Conservation Area

Male tiger swallowtail at Sericocarpus. Heart Island Conservation Area

One big difficulty in interpreting color patterns and their functional significance lies in the realization that human observers often aren’t even seeing the color patterns other butterflies, or their predators such as birds, might be seeing.  Many insects and some birds can see well into the ultraviolet range of the color spectrum, invisible to humans.    Butterfly wings (and flowers as well) reflect heavily in the UV, so what appears to be a single color without any obvious pattern to us is richly patterned to a potential predator, conspecific, or nectarivore.

Viceroy at Sericocarpus. Heart Island Conservation Area

Viceroy at Sericocarpus. Heart Island Conservation Area

Even in species where we think we have a clear understanding of the significance and evolutionary logic behind butterfly color patterns, the full story is sometimes more complex than initially imagined.  Take Viceroys, which traditionally have been considered to be a classic (Batesian) mimic of the unrelated monarch butterfly.  Any decent naturalist can tell a monarch from a viceroy pretty easily; not only are there differences in specifics of the color pattern (especially a transverse black band on the upper hindwing of viceroys, lacking in monarchs), but also major differences in flight patterns.  Still, as the old story goes, viceroys gain protection from predators because of their similarity to monarchs (and other danaids like queen butterflies).    Monarchs are avoided by many predators because they feed on and store (sequester) toxic compounds from their larval hostplants, which include various species of milkweeds (Asclepias spp) and relatives (such as Sarcostemma).   These compounds, called cardenolides, cause fairly immediate digestive upset in naïve predators that try to eat one, and they quickly learn to avoid any similar appearing butterflies in future feeding attempts.  Monarchs have evolved a bright and conspicuous orange and black color pattern to warn potential predators of their toxicity. This pattern of warning coloration is known as aposematic coloration.

Monarch (Danaus plexippus). In the traditional explanation, the monarch is the model (unpalatable species) for the viceroy (palatable species) in a Batesian mimicry system

Monarch (Danaus plexippus). In the traditional explanation, the monarch is the model (unpalatable species) for the viceroy (palatable species) in a Batesian mimicry system

Viceroys, the willow feeders, were long considered to be perfectly edible, palatable insects that gained some protection by their resemblance to the emesis-producing monarchs.  In a series of clever experiments, lepidopterist and evolutionary biologist David Ritland showed back in the 90’s that in some areas like south Florida, viceroys are actually more distasteful and unpalatable to bird predators than co-occurring populations of monarchs or closely related queens.  The monarch and queen larvae in these areas feed mostly on species of milkweed (Asclepias tuberosa, Sarcostemma clausum) that have very low concentrations of cardenolides, leaving the danaid butterflies (monarchs and their relatives) relatively palatable.  The viceroys, by contrast, sequester toxic phenolic glycosides from their willow hostplants.  When abdomens of viceroys and queens were offered to predatory birds (red-winged blackbirds) in the lab, the birds rejected the viceroys more often than they did the queens.  So in some areas, viceroys are apparently the more distasteful model (or co-model, in a form of shared aposematism called Mullerian mimicry) and monarchs and queens the more palatable mimics.

Viceroy with wing damage suggestive of a predator attack. Notice the symmetrical chunks missing from both hind wings, and the V-shaped pieces missing from the left wings. Most likely, a predator (bird, lizard?) grabbed the wings while this butterfly had them folded.

Viceroy with wing damage suggestive of a predator attack. Notice the symmetrical chunks missing from both hind wings, and the V-shaped pieces missing from the left wings. Most likely, a predator (bird, lizard?) grabbed the wings while this butterfly had them folded.

So maybe in science, as in life, a little humility is a good thing.  It’s often the case that we don’t understand complex natural systems as well as we think we do on first consideration.

FOS birds and what they’ve taught me

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October 6, 2013

For those who aren’t at least mildly manic about all things birds, FOS stands for First Of Season.  In both migrations, I look forward with great anticipation to each and every FOS, as do most birders.  We’re all addicted to the thrill of the new, even if it isn’t truly new.

House wren scolding me for no apparent reason.

House wren scolding me for no apparent reason.

My first real field guide when I became interested in birds was the venerable Golden Guide to North American Birds, by Chandler Robbins et al.   A truly revolutionary field guide in so many ways, and still one of my favorites.  For the first several years as I was learning northern Virginia birds, I made a note of the FOS date in my copy of Robbins (which I still have, dogeared and held together by duct tape) of the migrants that I saw regularly.  After a few years, a remarkable fact became apparent to me – the FOS dates for many species were stunningly regular and predictable, sometimes within a day or two of each other each year.   So the first thing FOS birds taught me was that the natural calendar has a great constancy about it.   Not exactly a world-changing revelation, but it seemed so to me at the time.  I could actually anticipate and savor the idea of seeing some of my favorite birds at a fairly specific time each year.

Male bobolink in breeding plumage. Emeralda Marsh Conservation Area

Male bobolink in breeding plumage. Emeralda Marsh Conservation Area

These days FOS birds fall into two fairly distinct groups for me.  One comprises the transient migrants, who will pass through in a fairly short period of time, not to be seen again until the next migration, or in some cases, until the next year for species that shift their migratory pathway between fall and spring.  These transient migrants are always a thrill, partly because of the ephemeral nature of their passage.  In Florida, the species that epitomizes this group for me is the bobolink, which I typically see in Volusia County for only a couple of weeks, beginning in late April and extending sometimes to the second week of May.  I can’t think of many sights or sounds that stir my heart more than a flock of hundreds of bobolinks, males in full breeding plumage and constant boisterous song, working their way through a wet successional field in synchrony, disappearing and then leap-frogging each other in methodical waves.  The beauty of the transient FOS species is quite obvious – they will soon be gone, not to be seen again until another half-year rolls by.

Gray catbird. Lake George State Forest

Gray catbird. Lake George State Forest

But the more informative group of FOS bird is for me the winter residents.  Especially in Florida, where we are gifted with such a rich and diverse wintering bird fauna, these birds can appear any time between mid-summer (prairie warblers, for example, a few of which will remain to winter here) and late fall-early winter (huge flocks of American robins and cedar waxwings come to mind).   Throughout fall migration, the anticipation of newly arrived winter residents is a powerful motivator to entice me into the field.  Right now, we are in the midst of a mini-wave of arriving winter residents – I saw my FOS common yellowthroats, house wrens, eastern phoebes, palm warblers, and gray catbirds in the last week or two.

Male common yellowthroat in a red maple swamp. Lake George State Forest

Male common yellowthroat in a red maple swamp. Lake George State Forest

Palm warbler, western subspecies. Heart Island Conservation Area

Palm warbler, western subspecies. Heart Island Conservation Area

Here’s what FOS winter residents have taught me, and reteach me every year.   There is immense beauty and joy in the plain and the regular.  House wrens are a case in point.  Not the most strikingly beautiful passerine, unless you’re really into brown, drab birds, but what they lack in superficial glitz they make up for in attitude and belligerence.   Within a couple of weeks, I will inevitably begin to take these scolding little scuts for granted, much as I habitually do with most of our common permanent residents.  I see this dynamic played out in others every time I teach Ornithology.   Within a week or two after the semester has begun, as we begin to accumulate a respectable species list, even the newly minted birders in the class begin to develop this unconscious devaluation of common birds.  Even spectacular common birds.  I’m sure this thought has been shared by many others, but I tell these nimrods every semester that if one saw a northern cardinal only once in her life, for most it would be an incomparably treasured memory.   I still vividly recall the reaction of Sabrina Krisberg, an enthusiastic student from over a decade ago, when she got her first look through binoculars at a male cardinal in rich early-morning light.   She slowly whispered in a voice full of awe and reverence, “It’s so perfect”.

Female common yellowthroat. Lake George Conservation Area

Female common yellowthroat. Lake George Conservation Area

Male common yellowthroat. Heart Island Conservation Area

Male common yellowthroat. Heart Island Conservation Area

So even though I know the magic and exhilaration of seeing a FOS bird each fall is transitory, and within weeks I will be shrugging off house wrens and gray catbirds, their appearance each fall teaches me again that there is immense beauty and spectacle right in front of me every day.   It’s so easy to become complacent and jaded by the familiar, of every sort.  I hope that these sometimes plain, and often obscenely abundant (think yellow-rumped warbler here) FOS birds remind me each season not to take any of this beauty for granted.   The beauty of my everyday life – a job I (mostly) love to go to each day, the wonderful friends I love so deeply, and good people in general;  it’s far too easy to forget how incredibly fortunate and privileged I am for the many gifts that surround me every day.

Eastern phoebe. Lake Dias Cemetery

Eastern phoebe. Lake Dias Cemetery

And it’s all so vanishingly brief.  I’m no Roy Batty, but I fully understand what he meant.  I’ve never seen attack ships on fire off the shoulder of Orion, but I have seen FOS house wrens chattering at me from a thicket in October.    And as my friend John Jett is fond of saying, that’s a beautiful thing.

Female common yellowthroat. Lake George State Forest

Female common yellowthroat. Lake George State Forest

The second wave

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Setember 20, 2013

Fall migration, for many of the bird-obsessed like myself, is the best time of year to be in the field.  Spring may bring males in peak breeding plumage and song, but the sheer numbers of birds make fall migration more spectacular for  me.  Especially given the eccentricities of Florida’s seasonal variation in bird diversity (low breeding diversity, high wintering passerine abundance and diversity, highly variable numbers of migrants making landfall in the state during spring migration), fall migration is to many Floridians what spring migration is to those further north – the end of a period of relative bird paucity.   Our summer bird fauna is the analog to their winter bird fauna.  Of all of the neotropical migrants that pass through Florida in the fall, warblers are for me the glamour group.  Don’t get me wrong – I get jazzed about any new arrival, but nothing gets me as excited as seeing and photographing warblers.

It’s pretty simple, really.    Bright colors, high diversity, and the challenge of identifying immature and female birds all combine to make this family my favorite.   Adding to their allure is the fact that warbler migration is such an extended phenomenon, lasting from mid-summer until nearly true winter.   The seasonal trends in abundance of the different warbler species passing through or wintering in Florida are as diverse as the birds themselves.

Common yellowthroat male. This is most likely a first-winter bird based on the somewhat poorly defined mask.

Common yellowthroat male. This is most likely a first-winter bird based on the somewhat poorly defined mask.

We are now in the midst of what I consider to be the second wave of warbler migration – the influx of migratory populations of common yellowthroats into the state.  I saw my first migrant common yellowthroats a little over a week ago, and this morning at Tiger Bay State Forest, they were the most abundant of the warbler species.  Their numbers will continue to rise for the next week or two.

Common yellowthroat female.

Common yellowthroat female.

Although 43 species of warbler can be found at one time or another in the state (this includes the most likely extinct Bachman’s warbler), warbler migration in the peninsula is dominated by a relatively small number of species.    In my experience, fall warbler migration can be categorized as a series of 4 waves of birds passing through the state at different times.     The figures below are based on data I collected at Emeralda Marsh Conservation Area in Lake County between 2000 and 2006, and should be interpreted with some caution – they are certainly not representative of the entire state, or even the entire peninsula.   Any general conclusion is only as good as the sample it is based on, and my bird censuses at Emeralda constitute a biased sample.  I think it’s a fairly decent proxy for warbler migration through the interior of the peninsula, since the 7000 or so acres comprising Emeralda contain a decent variety of many of the terrestrial and wetland habitats in central Florida.  But not all major habitat types are represented – scrub, sandhills, and flatwoods are all absent from Emeralda, for example.   Although ovenbirds were regular fall migrants at Emeralda, I never saw them there in the numbers there that I sometimes find in other upland habitats like scrub.  It also seems clear to me that there is a fundamental difference between warbler migration at some coastal locations and those inland.  In the seven years I did weekly bird censuses at Emeralda, I rarely encountered some warbler species that can at times be fairly common at coastal locations; this group includes species such as hooded and worm-eating warblers.

Seasonal abundance of the five most common warbler species at Emeralda Marsh Conservation Area in Lake County. I found around 25 species of warblers there over the years, but these 5 were far and away the most abundant.

Seasonal abundance of the five most common warbler species at Emeralda Marsh Conservation Area in Lake County. I found around 25 species of warblers there over the years, but these 5 were far and away the most abundant.

The first wave of warbler migration at Emeralda  begins in late July, and peaks in September, and is due to two species with roughly similar timing of passage – prairie warblers and yellow warblers.   I’ve mentioned the spectacular numbers of yellow warblers during fall migration at Emeralda in a previous post, emphasizing that the high daily counts (over 100/day on good days) are probably somewhat unique to the specific combination of habitat characteristics there.  Prairie warblers are much more generalized in habitat choice, and can be abundant early in the fall migration period in just about any habitat, including scrub.

Prairie warbler, from Ocala National Forest.

Prairie warbler, from Ocala National Forest.

 

Yellow warbler, from Occoquan Bay NWR in Woodbridge, VA

Yellow warbler, from Occoquan Bay NWR in Woodbridge, VA

The second wave is just beginning – the arrival of the common yellowthroats.   This species is particularly interesting to me because it is one of the few warblers that breeds in Florida.  Though fairly catholic in choice of breeding habitat (ranging from freshwater marsh to pine flatwoods), the population of breeding birds is dwarfed by the influx of migrant birds from northern populations, as seen in the graph below.

Seasonal abundance of common yellowthroats at Emeralda Marsh Conservation Area

Seasonal abundance of common yellowthroats at Emeralda Marsh Conservation Area

The third wave occurs in another couple of weeks – the arrival of the palm warblers, many of which will spend the winter in the peninsula.   I’ve been hearing reports of small numbers of palms showing up in the last week or two, though I haven’t seen any yet.

Palm warbler, the third wave of warbler migration.

Palm warbler, the third wave of warbler migration.

Finally, the fourth and final wave is the appearance of the yellow-rumped warblers, which will begin appearing in late October and continue to increase in numbers for the next several weeks.   Butterbutts will become so abundant that they totally dominate the wintering warbler community, much to the displeasure of some birders.    Picking through a flock of dozens or hundreds of yellow-rumps in attempt to find something “good” hidden amongst can be a challenge.   The appearance and ascendance of the yellow-rumps also marks the end of major warbler influx into the state.

Yellow-rumped warbler, the fourth and final of the warbler waves.

Yellow-rumped warbler, the fourth and final of the warbler waves.

It’s hard to harbor negative feelings about the super-abundant yellow-rumps, though.   While birders in most of eastern North America are pleased to find a handful of yellow-rumps on a winter birding trip, winter birders in Florida can count on finding as many of them as we could want, along with smaller numbers of 6 or 7 other warbler species on a good day.  And that ain’t too shabby.

Seasonal changes in warbler diversity at Emeralda Marsh Conservation Area

Seasonal changes in warbler diversity at Emeralda Marsh Conservation Area