Orange-crowned warbler.

December 28, 2013

A number of common Florida birds are named for features that are rarely seen.  Ring-necked ducks, ruby-crowned kinglets, and bristle-thighed curlews come to mind.   This morning I was relaxing on the patio, savoring my best Christmas present, Joe Hutto’s endearing Illumination in the Flatwoods: A Season With the Wild Turkey.  I watched and listened as numerous flocks ranging from a few to several dozen American robins flew over regularly; it seems that they are beginning to shift to their urban phase.  While totally mellowing on this gorgeous gray Florida day,  I was fortunate to not only see, but also photograph a feature of one of these common Florida birds that I’ve seen only a few times.  Ever.  The orange crown of an orange-crowned warbler.  (If you’re still scratching your head about the bristle-thighed curlew reference above, give yourself a pat on the back; it’s a joke.  I’ve never seen one, in Florida, Hawaii, or elsewhere.)

Ruby-crowned kinglet, showing not a hint of a ruby crown.

A low-intensity display of the ruby crown.

Many birds have plumage or structural features that serve as signals of some sort, and which can be widely variable in strength, or even their presence or absence.  These graded signals allow nuance in communication between individuals.  Exactly what is being communicated is often (usually?) hard to determine.  Ruby-crowned kinglets have been tormenting me for years in my quest to photograph the full blown crest erection.  Haven’t come close; a patch of red laid flat along the crown is the best I’ve been able to manage so far.  I see ruby-crowns displaying their brilliant crest often enough that I have some intuition of its message – it seems to be an aggressive display towards conspecific males, and the degree of piloerection is an index of level of bad intent.  Males will occasionally flare their crest in response to playback of ruby-crowned kinglet vocalization (though not while mobbing, suggesting it is a signal for conspecifics), and when interacting in chases and aggression with other males.

One of the more nondescript of Florida’s winter warblers, if it doesn’t show any prominent field marks like wing bars or head pattern, it could be an orange-crowned warbler.

In orange-crowned warblers, I’ve seen even a smidgen of the orange so few times that I have no idea when or how they deploy their display.  A Google image search for orange-crowned warbler returns a ton of very nice images, but only a handful show any sign of the orange crown.  And most of those are birds being held in the hand.  My inference is that orange-crowned warblers never flare the crown to the degree sometimes seen in a highly agitated ruby-crowned kinglet, in which the red cap looks more like a mohawk than it does plumage.

Northern cardinal male with flattened crest. What signal is being sent, and to whom?

A more typical crest position.

Feather position alone can act as a graded display, with or without display of normally hidden color.  The degree of elevation of the crest on a northern cardinal changes dramatically, occasionally disappearing entirely when an individual is alone and presumably totally mellowed out.  For cardinals and blue jays, the erect crest is the default state.  For many other “uncrested” birds, the flathead is the default state, and a prominent crest is displayed only briefly and infrequently.  Think green heron here.

Chill green heron.

Mildly perturbed green heron.

Seriously pissed off green heron. Not surprisingly, it’s a teenager.

In other birds, the signal is always visible to some degree, but that degree varies tremendously.  Male red-winged blackbirds sometimes throw me for a loop when I see them with their orange and yellow epaulets nearly totally concealed by other feathers.  If I miss the sliver of yellow visible, I’ll begin to try and turn the bird into a more uncommon blackbird.   At full display in a singing male, the epaulets are like brilliant orange-red flames.

Red-winged blackbird trying to conceal his true identity.

Full display.

Though I almost never see their orange crown, I see orange-crowned warblers fairly often, usually as single birds traveling with mixed-species winter flocks that can include titmice, chickadees, yellow-rumped warblers, kinglets, gnatcatchers, and small numbers of a half-dozen or more small passerines.  I love mixed-species flocks.   Orange-crowneds are one of the latest of the wintering warblers to migrate into Florida;  while doing my Emeralda bird surveys, they usually didn’t appear until the third week of October or the first of November.  Between then and their departure in late March (late entry, early exit), I saw on average 2-4 birds per census.  Rather slow, deliberate leaf-gleaners for the most part, in low- to mid-level vegetation.   They seem to like to investigate clumps of dead leaves.  I once photographed one at Merritt Island NWR feeding on a large inflorescence of the flowering vine Mikania scandens; it was feeding on insects attracted to the flowers as well as on floral nectar.  Orange-crowned warblers will puncture the base of some long-tubed flowers to gain access to the nectar.  Seems like a very tropical behavior to me, though many of these birds will remain in the mild but temperate southeast for the winter.

Checking out the dead leaves.

Nectaring and gleaning at Mikania scandens

Feeding on nectar/pollen of willow.

Through most of the winter in Florida, the orange-crowned warbler is a very reliable bird, though I never see them in large numbers.  I once saw a small flock of 4 traveling together in my backyard; they were leaf-bathing on a drizzly February afternoon in the wet foliage near the top of a big Senna bicapsularis.  I saw a hint or two of the orange crown on that day as well.

Seasonal abundance at Emeralda Marsh Conservation Area, Lisbon FL.

Leaf bathing in Senna bicapsularis

The bathing orange-crowned today was taking the more formal soak and fluff in the birdbath, and I was able to watch him (only males have the orange crown, which probably says something about its function) for a couple of minutes.  The orange crown was frequently visible, though it was probably coincidental to the normal feather fluffing and puffing that bathing birds do.  There were no other orange-crowned warblers, or birds of any other species that I was aware of, nearby that this little guy might have been signaling to.  Perhaps the relatively low population density of orange-crowned warblers accounts for some of the rarity of the display, especially when compared with the somewhat similar appearing ruby-crowned kinglets, which are typically much more abundant than orange-crowneds, and which often occur in larger numbers in mixed-species flocks.

I have to think even a highly enraged orange-crowned warbler’s display is still pretty subdued.   The species account at Cornell’s Birds of North America Online has this brief tidbit (from Arthur Cleveland Bent’s monumental multivolume set of life histories of North American birds) about the orange crown display:  “Male threat or alarm display can involve elevation of head feathers to display (barely) the orange crown patch (Bent 1953).”  As graded displays go, the orange-crowned warbler’s is quite modest.  So why does it give me such a thrill to see it?

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

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.

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

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

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

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. is easily recognizable, unlike my other home corvids.

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.

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.

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 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 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.

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.

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. 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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

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

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

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

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.

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.

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.

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.

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

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.

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.

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