Browsed by
Category: Behavior

Video Library: Large Gulls

Video Library: Large Gulls

The internet is full of wild bird videos.  If you want to learn about behavior and vocalizations, it can be a great place to start, at least for certain species.  Gulls are a terrific example.  They’re loud, they’re conspicuous, they’re tame, and when engaged in their behaviors, they ignore gawking humans with videocameras.  I was able to observe more behaviors from more gull species in a few hours on YouTube than I could have seen in a couple of weeks at the beach.

Today, I share the fruits of my labors, categorized by species and behavior type.  This is nowhere near comprehensive — each time I go back to the internet, I find more videos worth including.  I’ve had to limit this to the large gulls (genus Larus) for now, and even so, many species aren’t even represented here at all yet. If you find footage worth including, please leave a comment or shoot me an email and let me know.

For an introduction to the gull behaviors mentioned here, see my last post.  Enjoy!

American Herring Gull

Cornell’s “How Nature Works: Gull Territoriality” — a good overview of gull behaviors, starring mostly Herring Gulls and a few Great Black-backeds

Aggressive encounter with “mew” duet, “choking” display, and fighting. Connecticut, late fall.

Pair of Herring Gulls giving head toss / courtship begging calls, then copulating (loud narration by people nearly throughout)

Copulating pair in Rhode Island (voices of birds hard to hear)

Two juvenile Herring Gulls giving begging calls (July, Saskatchewan)

Glaucous-winged Gull (and/or intergrades)

A pair of apparent Glaucous-wingeds in a park in Washington State in spring — probable courtship behavior, including Mew calls.

A pair-bonding display between two Glaucous-wingeds or possible intergrades: one bird (perhaps the female) gives the Head toss / food-begging call, and the other bird regurgitates a fish

Pair on streetlight, head-tossing, with some begging bill pecks, and accompanying calls; species ID not clear

Western Gull

Pair of apparent Western Gulls giving Mew calls, perhaps some “Choking” displays, then fighting at end:

Solo Western Gull giving a few Mew calls. Catalina Island

Pair fighting with bills locked, apparently without vocalizing; then they break apart and give multiple Long Calls; then a more violent, briefer fight; then the victor struts around giving some low grunts and a final Long Call

Six nice food-begging calls given with head-tosses by one member of a pair on Alcatraz

Female giving head-toss begging call; male quickly mounts; eventually copulation begins accompanied by male copulation grunts. Audio rather terrible. Near Fisherman’s Wharf, San Francisco.

Copulation with decent audio of male copulation notes. Start and end not shown. La Jolla, California

Copulation; video rather brief but audio decent, with the exception of one comment in middle by videographer

Two Western Gulls fighting in parking lot, giving kek-kek calls (alarm chuckles) constantly. Video from second-story deck with commentary.

Heermann’s Gull

Two nice Long Calls, display postures and all, from one individual

Very brief video of some rapid nasal series, including some possible Long Calls

Iceland Gull

Iceland Gull calls once, rather faintly, near the end of this video (short low nasal bark):

Lesser Black-backed Gull (subspecies graellsii or similar)

One nice Long Call with full display postures, Liverpool, UK:

Closeup of a bird giving alarm chuckles and one Long Call with medium-strong display postures; a little disruptive wind noise:

Pretty cool territorial interaction between a Lesser Black-backed and a European Herring Gull – a Long Call duet at the start, then lots of Mew calls. A few chuckles and “how” calls from the Lesser Black-backed after it wins the fight.

Pair of Lesser Black-backeds Mew-calling in duet; some choking grunts while crouching on ground. Don’t miss Maarten van Kleinwee’s fascinating blog post about this pair and its behavior.

Feeding frenzy of birds, in Iceland in late May, being fed bread. All or mostly Lesser Black-backeds. Plenty of single-note calls.

Adult giving nasal “how” calls, with same from background birds

Alarm chuckles and a few decent mews; then a good long series of a duet of yelp calls; no head-tossing or other obvious displays; context uncertain. Near Reading, UK

Close-up of bird giving a few alarm chuckles. Alkmaar, Netherlands.

What Gulls Say

What Gulls Say

Have you heard an Ivory Gull vocalize? I have! (Didn't get any recordings, unfortunately.) Photo by Martha de Jong-Lantink, Spitsbergen, 8/19/2008 (CC 2.0).

Gull enthusiasts are weird.  They hang out at landfills.  They go to the beach when it’s freezing cold, or just to see what’s in the parking lot.  They’ll stare at a single bird for hours, puzzling over insanely minute details – the precise shade of gray on the back as measured by the Kodak gray scale, the age and condition of individual feathers, and even (I am not joking) the color of the inside of the bird’s mouth.  When it comes to identifying a mystery gull, they look at everything; they ignore nothing.

Except vocalizations.

Gulls have voices, but you’d hardly know it from reading the identification literature.

In all the thousands and thousands of words written each year about gull identification by experts on the ID-Frontiers listerv, vocalizations are mentioned approximately never.  P.J. Grant’s classic book Gulls: A Guide to Identification contains not a single mention of voice.  Howell & Dunn’s Gulls of the Americas refers to voice only in passing, in the introduction, and omits it from the species accounts. Olsen & Larsson’s authoritative Gulls of Europe, Asia and North America briefly mentions only a few sounds for each species.

I think the general neglect of voice can be explained by three factors:

  1. Gull sounds are variable.  Two individuals of the same species may sound very different.
  2. Gull sounds are plastic. Two calls from the same bird may sound very different.
  3. Gull sounds are poorly understood.

Those first two problems are not to be underestimated. Until recently, my main experience with gull sounds came from attempting to record some Ring-billed Gulls fighting over some bread I’d thrown them.  I was astonished (and frankly intimidated) by the huge variety of sounds I heard.  They whistled, they squealed, they barked, they bleated, they gargled:

I really couldn’t make sense of it.  Could these vastly different calls be merely variations on a simple-minded expression of hunger?  I began to worry that gull sounds might well be too variable to be of much use in identification.

Then I had another experience that changed my perspective.

The Western Gull Rosetta Stone

Long Call posture, held for most of the call after the initial bow. Herring Gull shown; Western is similar. From Tinbergen 1960a.

Last month I attended the Western Field Ornithologists’ Conference in Petaluma, California, where I tracked down local gull expert and field guide author Steve N. G. Howell for an answer to my burning question: “Where can I record gulls around here without too much ocean noise?”

After some thought, Steve sent me to the parking lot at Stinson Beach. It was just what I was looking for: an open, public area only a few yards from the ocean, but sheltered from the surf noise by a nice high earthen berm.  I got there early in the morning and found myself alone in the parking lot with a couple dozen gulls of two species (Heermann’s and Western).  Conditions were good, but even so, I was unprepared for the show.

It started when a pair of Western Gulls broke into a Long Call Duet.  Standing close together, they bowed their heads down once toward the pavement and then stretched their necks out at a 45-degree upward angle for the rest of the call:

Western Gull long call duet, Stinson Beach, CA, 9/29/2012.

Immediately, both birds transitioned into a slow series of long, rising wails, much like the sounds of a peacock, as they strutted around the parking lot in parallel, necks fully extended, bills pointed downward:

Western Gull "mew" duet, Stinson Beach, CA, 9/29/2012.

"Mew" duet posture. From Tinbergen 1960a.

Then one bird picked up some leaves and twigs in its bill.  It crouched down on the ground as though it wanted to begin building a nest scrape, or perhaps as though it were soliciting copulation. It began giving short, quiet grunts while its partner continued to wail occasionally:

Western Gull grunts during "choking" display, Stinson Beach, CA, 9/29/2012.

"Choking" display, from Tinbergen 1960b.

Just when I thought the show couldn’t get any better, a third Western Gull flew in, and one member of the duetting pair charged off to confront it.  The two locked bills in an intense tug-of-war, wings out for balance, giving a soft but threatening chuckle vocalization:

Western Gull alarm chuckle, Stinson Beach, CA, 9/29/2012.

Herring Gulls fighting, from Tinbergen 1960b.

Fans of Alfred Hitchcock may remember that chuckle — it’s the sound dubbed into The Birds whenever the Western Gulls gather ominously.  (Hitchcock added a little echo, to make it even spookier.)

When I got home, I discovered I’d recorded over half an hour of this remarkable show, and an additional ten minutes or more of myself narrating behavioral notes into the microphone.  It was the highlight of my entire trip to California.

Surprise, Surprise

The distinctiveness of each of the sounds I recorded, and the fact that each was obviously tied to a different social context, gave me a whole new view of gulls and their vocalizations.

Because I made those detailed notes on the posture and context of each sound, I was able to match each one up pretty well with the established literature on gull vocalizations (especially the pioneering work of Niko Tinbergen 1960a, 1960b).  The peacock-like wail is called the “Mew” call; the grunting accompanies the “Choking” display; and the chuckle is known as the alarm call.  Clearly, at least some of the time, gulls are more than just screaming kleptomaniacs.  They are capable of wonderfully complex and evocative social communication.

Flirting or Fighting?

My original hypothesis was that I was observing courtship behavior, but this may actually have been an aggressive territorial encounter, perhaps between two males. All of these displays are used in both aggression and in courtship.

Supporting the courtship hypothesis is the fact that this duetting pair never resorted to fighting.  When a third bird arrived, one of the displaying pair fought it off, while the other member of the pair looked on in agitation, giving a very long Long Call sequence.  When the third bird was driven off, the pair display resumed immediately between what I took to be the original two birds.

Furthermore, this pair’s strutting dance didn’t seem restricted to any territorial boundary. Instead it rambled over hundreds of yards of parking lot, seemingly at random.  Every once in a while the two birds would break off and drift apart, silently or with a few chuckle calls.  Once, when the two birds were widely separated, one of them crouched without apparent provocation and started giving a series of “Choking” grunts.  The second member of the pair immediately began walking towards it from a hundred yards away, taking up the wailing “Mew” cry when it got close.  The entire episode seemed to have the air of solicitation rather than confrontation.

Supporting the territorial interpretation, however, is the fact that it was late September.  Western Gulls aren’t supposed to start pairing up for mating until January at the earliest.  I couldn’t tell the sex of the birds. Although I kept expecting copulation to occur, it never did.  Nor did I see any of the unambiguous pair-bonding displays, such as the regurgitation of fish, which is the gull equivalent of recreational sex.

Gulls of several species have been reported to defend winter feeding territories, and that could have been what these birds were doing.  Perhaps a local breeder was fending off an interloper in search of winter turf.

The Take-Home Message

Somewhere near you, right about now, a pair of gulls is about to engage in a loud and conspicuous display.  They’ll do it wherever they find themselves — in a park, on a city street, at the grocery store — with little regard for what’s around them.  You’ll be able to walk right up to them with your camera, your smartphone, your recorder.

Do it.  Take notes on what you see.  Post your resulting pictures/video/audio to Flickr/YouTube/Xeno-Canto.  Then drop me a line.

We don’t know enough about gull displays, especially not in fall and winter.  Most research on gulls has taken place on the breeding grounds, and it’s possible that we don’t know about autumn courtship because we haven’t been paying attention.  We also don’t know much about identifying gulls by voice — but all we need to do is listen.  By sharing our observations online, we have the power to learn a ton.  Let’s give it a try.

The Left-handed Blackbird

The Left-handed Blackbird

What bird species always twists its head to the left when singing, never to the right?

When I came upon the claim in the scientific literature that singing male Yellow-headed Blackbirds always turn their heads to the left and never to the right, I immediately had to verify it for myself.  Since the migratory Yellow-heads in my neighborhood have mostly skipped town, I went where the birds are always singing: YouTube.

As far as I can tell, the claim is correct.  At least, I haven’t been able to find a video yet that disproves it.  But let’s be exact: each male Yellow-head has two different kinds of advertising songs, and only one of them is accompanied by the leftward head-twist.  Some researchers call these two song types the Accenting Song and the Buzzing Song.

The Accenting Song (of short, somewhat musical notes):
is given in the Symmetrical Song Spread display posture:

Illustration from Orians & Christman 1968.
The Buzzing Song (a marvelous yowl like a dying cat’s):
is given in the Asymmetrical Song Spread display posture (with the left wing raised and the head turned left):

Illustration from Orians & Christman 1968.

Some caveats apply, of course.  The display postures illustrated above are typical of excited males. When the birds are less motivated, they may move their wings and head very little.  But the fact remains that in the dozen or so YouTube videos that I watched, if the head moved at all during the Buzzing Song, it always went to the left.

This is not the only instance of “handedness” (what scientists call “chirality” or “laterality”) among birds.  Parrots have been reported to be mostly left-handed; so has at least one individual Short-eared Owl (in a series of stunning photos).  Preference for one foot or the other has also been reported in a few species of Central American finches.

It’s not just feet, wings, and heads that may be lateralized.  Some birds show a preference for using one side of the syrinx when vocalizing. And a few birds have physical asymmetries: the New Zealand Wrybill has a bill that is always bent to the right.  In the White-winged Crossbill, the lower mandible crosses to the right in approximately 75% of individuals. In its relative the Red Crossbill, however, the lower mandible crosses to the right in about half of birds, and to the left in the other half.

The authors of the parrot study go so far as to speculate that handedness may have originally evolved in species that, like parrots, have eyes on the side of their head — and so must choose a direction to turn each time they want to look at something dead ahead.  Whatever the reason, this is an aspect of bird behavior that is easily observed and quantified — but usually ignored.

I know I’ll be paying more attention to the singing Yellow-headed Blackbirds when they come back north next spring!


The “Two-part Calls” of Empidonax

The “Two-part Calls” of Empidonax

If only it would sing! Probable Hammond's Flycatcher, Wyoming, 6/17/2010. Photo by Bryant Olsen (CC-by-nc-2.0)

Empidonax flycatchers are tough to identify by sight.  Every birder knows it.  They’re the classic bugaboo of North American bird identification.  That’s why every field guide mentions the importance of listening to their voices.

But Empids make a lot of sounds.  Forget about learning “the song” and “the call.”  Most Empids have repertoires of 6-8 different songs and calls. Some species, such as Pacific-slope and Cordilleran, have a dawn song that’s different from anything they say during the day.  Several, including Least, Yellow-bellied, Hammond’s, and Dusky, have complex, rarely-heard flight songs. The species with the largest vocabulary appears to be Acadian Flycatcher, which has all of the above types of song plus another type, sometimes called the “evening song,” which is the most complex of all.  (It may or may not be fully separate from the flight song.)

Today I’m going to be talking about a class of Empid vocalizations that don’t get much press. I’ll call them “Two-part Calls” since they don’t have an official name.  Based on their similarity, the “two-part calls” appear to be homologous — that is, evolutionarily equivalent, all descended from the same calling behavior of a common ancestor.

As far as I know, three species of Empids give these calls. In one species, the two-part call is familiar enough to be mentioned in field guides, at least. The two-part call of the second species is described only in the scientific literature.  And that of the third is, as far as I know, being described in this blog post for the first time.

Dusky Flycatcher: “Du-hic”

This call is mentioned in the Sibley Guide to Birds, Kenn Kaufmann’s Advanced Birding, and other well-researched field guides.  The “du” part of the call is nearly monotone, and the “hic” is shorter and slightly higher.  As you can hear in the following examples, the sequence is often more like “du, du, du, du, du-hic”.  Sometimes the “hic” notes will be given without a “du,” or after other “hics.”

This call may be given primarily by males, but I’m not certain of that. It’s given throughout the breeding season, but especially in long bouts at dawn and dusk during the early summer, prior to egg laying.

Hammond’s Flycatcher: “Peer-pewit”

Quite similar to Dusky’s “du-hic” but not mentioned in any field guides that I know, this call was first described in the scientific literature by James Sedgwick in 1975. Sedgwick called it the “k-lear whee-zee” call, but I think “peer-pewit” is a better transliteration. The “peer” note is slightly more downslurred than Dusky’s “du,” and the “pewit” is higher, longer, and much more distinctly two-syllabled than Dusky’s “hic.”  It’s given in similar situations to the “du-hic,” though it’s apparently  more likely to be heard later in the breeding season, after egg laying.

Yellow-bellied Flycatcher: “Whit-beert”

I stumbled across this vocalization in a good recording by Randy Little from Herkimer County, New York, which appears to be the only such recording in existence. The call is clearly related to the “du-hic” and “peer-pewit” of the western species, but instead of a drawn-out whistle, the first note is an emphatic “whit!” that resembles a more explosive version of the “whit” calls of other Empids. The second note is again an up-down-up trace on the spectrogram, rather like the Hammond’s “pewit” note.

Yellow-bellied Flycatcher "whit-beert" call, Woodhull Lake, New York, 5/30/1998. ML catalog #106901

(Click here to listen to the original recording on the Macaulay Library website.)

I cannot find any definite mention of the “whit-beert” call of Yellow-bellied Flycatcher in any published source.  The only possible reference I’ve found is this brief statement in the Birds of North America account:

One variation of Tu-Wee Call is of longer duration, described as thoo weep eh, thoo weep eh, or she weeps sir (Hausman 1946), or pea-wayk-pea-wayk (Dr. Hoy in Forbush 1927) and may actually represent call of different function.

That’s it.  Not much to go on.

So we’re left with more questions than answers.  Do other Empids give “two-part calls”?  What functions do they serve in each species?  Are they ever given by migrants?  Are they very rare in the Yellow-bellied Flycatcher, or merely under-reported?

I’d be interested to hear anybody else’s experience with this type of call in Empids.

The “Meaningless” Calls of Red-winged Blackbirds

The “Meaningless” Calls of Red-winged Blackbirds

Calling male Red-winged Blackbird, 16 May 2009. Photo by jessi.bryan (click for link).

“What does that sound mean?”

“What is that bird saying?”

Questions like these are an important entry point for many people into investigating bird behavior. One moment, they’re simply admiring a song, and the next moment, they’re noticing things — like a sudden switch to Sound B as a hawk flies over.

Once they’ve noticed it, they can hypothesize about it.  Maybe Sound B means danger. Maybe the bird is saying, “Look out, there’s a hawk!” Maybe Sound B is the aerial predator alarm call.

When people start drawing inferences like this, they’re taking an important first step towards being investigators of animal behavior — ethologists — rather than mere admirers of it.  It’s an exciting and significant moment in the relationship with nature.

But it’s only the first step. Most of us don’t have the time or the resources to take the second step, which is to methodically test whether our hypotheses are correct.  If we did, we’d often have to face the fact that we were wrong.

Red-winged Blackbird alarm calls

What does a male Red-winged Blackbird say when a hawk flies over?  Well, it could be any of these wildly different sounds:

It could be any of those sounds and a whole lot more. In fact, it’s very difficult to predict what a Red-winged Blackbird will say in response to a hawk.

A budding ethologist might think this a little strange.  Doesn’t a huge variety of “aerial predator alarm calls” risk confusion? Any blackbird who doesn’t get the message could be easy prey — so evolution would seem to favor a single alarm response that all members of the species “agree on,” so to speak.

One possible explanation is the existence of local dialects. Perhaps the Redwings in this particular marsh give a high downslurred whistle when a hawk appears, but the Redwings in the next marsh over give a three-noted “ti-ti-ti“. The form of the call might depend on location,  just as human alarm calls sound like “look out!” in New York, “pas op!” in Amsterdam, and “abunai!” in Tokyo.

Makes sense. Redwings do have local call dialects. The ones in this marsh do sound different from the ones in that marsh. But even that doesn’t explain the plethora of responses.

In a study published in 1986, Les Beletsky, B.J. Higgins, and Gordon Orians tested the responses of male Red-winged Blackbirds to a stuffed Cooper’s Hawk.  They already knew that each Redwing in their study area gave seven different calls, which they called”peet”, “check”, “chuck”, “chick”, “chonk”, “chink”, and “cheer”. They revealed the stuffed hawk to 32 calling male blackbirds, 21 of which quickly switched call types:

One male switched to “peet” upon detecting the hawk, 4 males switched to “check”, 4 switched to “chuck”, 3 switched to “chick”, 2 switched to “chonk”, and 7 switched to “cheer”.

To be clear: all the male blackbirds could give all seven calls. When they saw the hawk, they switched to a different call from the one they had just been giving. But Beletsky et al. realized that which call type they switched to didn’t matter. That’s because it was not the call itself but the change in calls that sent the alarm signal:

Male redwings apparently use call switching as a component of a general alert system. … Individuals shift from one call to another when detecting environmental changes such as the appearance of a predator or the sudden movement of an observer. Even a stone tossed into a male’s territory can elicit from him a call switch and contagious switching around the lake. When detecting a call change by one male, the predominant response of other males is to switch to the same call type. The new type then supercedes the previous one as background, upon which subsequent call switches can be detected and localized, i.e., the system is immediately “reset” to a receptive status, awaiting the next change to impinge upon it.

This alert system is a highly effective one, but it only works in Red-winged Blackbirds because a few specific preconditions are met:

  1. Red-winged Blackbirds nest in dense colonies where many nests are simultaneously vulnerable to the same predator, and communal vigilance benefits the entire group;
  2. Male Redwings are exceptionally vocal, calling nearly continuously throughout the day, rarely stopping for more than a minute at a time;
  3. Individual males have large repertoires of different call types, learned from and shared with neighboring males;
  4. All males are quick to match a neighbor’s new call type right after he switches.

This remarkable behavioral system demonstrates how wrong our anthropomorphic assumptions about communication can be.  It’s tempting to think of bird sounds as though they were words and phrases, as though it were always the form of the sound that encoded specific messages to the listener.  But that’s not how Red-winged Blackbirds work. In and of themselves, their many “alert calls” may be practically meaningless.  Instead, the “meaning” is carried by the relationship of a call to the ones around it in time and space — its position within the larger matrix of calling behaviors.

For me, at least, this study opened up a whole new way of thinking about bird communication.

A Canyon Wren Mystery

A Canyon Wren Mystery

Canyon Wren, Irish Canyon, Moffat County, Colorado. Photo by Andrew Spencer

It’s a commonly held conception that only male birds sing.  And for many birds in North America that is indeed the case.  However, there are cases of female birds that sing as well – finches, orioles, cardinals, and some warblers (occasionally), among others.  In North American wrens, for the most part, only the males sing, but  exceptions include House Wren, Cactus Wren, AND Canyon Wren.

This is in sharp contrast to tropical wrens, who have among the best female singers in the entire avian world.  Indeed, the duets of some of the South American wrens are probably some of the all time great bird sounds on the planet!  Take a listen to these two different subspecies of Plain-tailed Wren: XC42098 and XC58882.

Back up here in North America, the song of male Canyon Wren is among the best known (and most beautiful) of the sounds in the west, echoing off canyon walls just about anywhere with appropriate habitat – take a listen below.

But Birds of North America gives an interesting tidbit if you dig a bit further: “Both sexes sing, but female song is rarer and usually shorter.”  It goes on to describe a couple of female vocalizations, but without spectrograms and without a whole lot of detail.  So it is up to the observer to figure out what female song is when in the field.  A while back Nathan told me about this vocalization, and gave me a recording he made in Arizona that he thought was the female song, asking me to keep an ear out for it and to try to get a better recording.  I was intrigued – there’s little I love more than a bird sound mystery – so I edited the recording for playback and put it onto my i-pod (you can also hear another example at 46 seconds on LNS#21482).

A few weeks later I had my first chance.  I was in Irish Canyon in far northwestern Colorado, and I heard the liquid notes of a Canyon Wren song on a nearby cliff.  I walked over, and played the tape in the middle of the bird singing.  I was a bit startled at what happened next – the singing bird stopped, mid-strophe, and flew right in at me, calling loudly and angrily.  It was also giving an unusual call type (see below), and continued giving it for some time, from the middle of pinyon pine trees and on the ground.  Eventually it flew up to the top of a tree and started singing again, but still reacted the same way the next time I played Nathan’s recording. What it did not do, nor did any other bird in the area do, was sing the “female” song that I had on my i-pod.

I took this as something of a challenge.  That morning I played to three more singing Canyon Wrens.  All reacted to the track, though none as strongly as the first bird, but none responded with the same vocalization as the one on the tape.

Finally, about a week later, I hit pay dirt.  This time I was down near the town of Dinosaur, and I randomly played Nathan’s cut just to see what would happen.  I didn’t hear a response, and after waiting a couple of minutes I began to walk away.  Then there it was!  High up on the cliff was a perfect carbon copy of what I had just played.  I got a witness recording, and began to move in.  I was soon watching the bird as it sang from on top of prominent rocks, and after another quick playback, on some nearby tall shrubs.  To hear for yourself what it sounds like, take a listen to the cut below:

When I played the recording I had gotten to the bird in question it would react immediately and aggressively, flying in very close and giving the same vocalization back.  Interestingly, when I played back the normal song, it would barely react, at most just sitting up and looking around briefly.  Frustratingly, I was unable to ever confirm two birds at once, so I can’t say for sure that this is from a female bird.  However, about half an hour later there was a bird in the same territory singing the normal song, and when I played back the “female” song to that individual it didn’t react much at all, and the one time it did it came in low giving the same calls as the bird from Irish Canyon.  When I played the normal song back to it, though, it went ballistic, flying right in and singing at close range.

I also took photos of both birds, and examining these later I could see what I believe are differences between the two.  SO there seems to be a preponderance of evidence for there being two birds in the same territory.  And since one of those birds was singing normal song and acting in a territorial manner (and is thus, presumably, a male), it would stand to reason that the bird I recorded singing “female” song was, in fact a female.  But I can’t be certain, so I guess I’ll have to keep trying!

A Dove Detective Story

A Dove Detective Story

Singing White-winged Dove, Monterrey, Mexico, 4/11/2010. Photo by Ereenegee (CC 3.0).

I love an auditory mystery.

For many people, an avian auditory mystery is a “whodunit” — a quest to find out what species of bird is singing.  But my favorite mysteries are “why-dunits.”  These are puzzles solved not by the identity of the singer, but by the meaning of the sound.

Major why-dunits are more common than you might think.  Let me put it this way: it’s difficult to take your camera to a local park and capture a bird plumage or behavior that has never before been photographed.  But it’s about twenty times easier to make an audio recording of a call or behavior that has never before been audio recorded.  And finding out what kind of sound you’ve recorded takes real detective work.

This is a dove detective story.  A White-winged Dove detective story, to be precise.

Just the facts

Unlike any other dove species in North America, White-winged Doves regularly alternate two different songs, a long one and a short one.  The long one goes on for up to 10 seconds or so, ending with a distinctive sequence of alternating downward and upward voice breaks:

White-winged Dove long song, Sierra County, NM, 2/24/2008.

The short song is the four-note “who cooks for you?” phrase familiar to many people in the arid Southwest.  Note the long, breathy introductory syllable, which is only audible at close range (this will be important later):

White-winged Dove short song, Sierra County, NM, 2/24/2008.

That’s what White-winged Doves should say, according to the field guides.

The Strange Case of the Two-note Song

Where were you on the morning of May 16, 2009?  I was in Guadalupe Canyon, Arizona, a few hundred yards from Mexico, recording a dove sound unlike any I’d ever heard, an odd two-note phrase with the second half burry:

Unusual White-winged Dove song, Cochise County, AZ, 5/16/2009.

Like any good gumshoe, I first eliminated the usual suspects.  It wasn’t the usual song of the Mourning Dove (3-5 notes), Eurasian Collared-Dove (3 notes), Rock Pigeon (1 note), or Common Ground-Dove (1 note).  Inca Doves sing two notes, but this wasn’t like the typical song or even the courtship song of that species either.  I wondered briefly if it could be some rare vagrant from south of the border — Ruddy Ground-Dove, or perhaps Arizona’s first Red-billed Pigeon or White-tipped Dove — but no, I knew those songs and they sounded nothing like this.

The most likely scenario, then, was that I was hearing an uncommon vocalization type from a common bird.   Most dove species in North America have multiple vocalizations, named by ornithologists for their function — an “advertising coo” to catch the ladies’ attention; a “display coo” to get them out onto the dance floor; a “nest coo” to entice them home to the bachelor pad.  The “nest coos” in particular can sound quite different than the typical songs, and they are poorly represented in audio recordings.  Was this a new “nest coo” for my audio collection?

Whatever the two-note dove was, it seemed to be countersinging with a White-winged Dove giving the typical short song.  There were definitely two birds, because occasionally they would vocalize at the same time, but I could only see one White-winged Dove, and I couldn’t be sure whether it was making the typical song or the odd one.  When it flew away, both songs ceased.

Searching for Clues

I went to the Birds of North America account for White-winged Dove to see if the two-note song had been described.  But this only increased my confusion.  The account clearly described the long song and the short song as different forms of the “Advertising Coo,” but its description of the “Nest Coo” was also apparently a description of the short song:

“Nest” call apparently very similar, consisting of 5 syllables, 3 in first half and 2 in second half, a single growling note (first syllable) followed by 2 barking notes (second and third syllables) connected together and with rising emphasis in second bark, then 2 barking notes together with a falling inflection and last one somewhat prolonged ( Whitman 1919, Goodwin 1983).

The five-syllable “nest call” starting with a “growling note” is pretty clearly just the short song heard at close range.

There was no mention of two-noted calls or burry notes anywhere in the article.  I had to consign my weird recording from Arizona to the “unsolved mysteries” file until more information came along.

Reopening a cold case

In Mexico in 2010, I wandered for two weeks among courting White-winged Doves.  I didn’t hear or record the two-note song again, but I did find some clues that began unraveling the mystery.

For one thing, I witnessed courtship displays of White-winged Doves for the first time, as described in the BNA account:

Male perches on sturdy twig or branch while female rests nearby, watching behavior. Male lowers body forward, head almost below level of perch, raises wings straight up and over body, lifts and fans tail, and rocks backward to normal perching position.

What the BNA account barely mentions is that the male gives the short song as part of this display.  From the vocal notes on one of my recordings:

He’s sticking his wings out at a 45 degree angle above his body and a little bit in front of his body.  They go up at the very beginning of his call, during that first note.  They come down slightly emphatically right at the beginning of his second note, at the beginning of the “cooks” note.  They’re kind of held stiffly there for that brief moment in between.  He’s orienting a couple different directions as he does this; he’s got his tail kind of stuck up into the air.

That flick of the wings at the beginning of the short song has the effect of flashing the white wing patches conspicuously, so that the audio and visual parts of the display are closely coordinated.  The BNA account suggests that both the long and the short songs may be used in courtship, but it gives few specifics.  I never heard the long song in conjunction with a visual courtship display.  All of this suggests that the short song might best be described as the “Display Coo” rather than the “second Advertising Coo” — though it is certainly given in many contexts other than the display, and far more frequently than the “Display Coos” of other dove species.  If the short song is equivalent to the “Display Coo” of other doves, then the rare two-note call could perhaps be the equivalent of the “Nest Coo.”

But another clue from Mexico might point in a slightly different direction.  As I was recording another courting male White-wing, I realized I was hearing two birds duetting from somewhere up in the tree, although only the wing-flashing male was visible.  One of the birds was doing the normal four-note short song, and the other was giving an abbreviated three-note version:

White-winged Dove three-note song, El Cajon, Sonora, Mexico, 6/30/2010.

This three-note song is clearly intermediate between the two-note Arizona recording and the typical short song.  The first note is almost identical to the Arizona bird’s: a breathy growl becoming a coo with an upward-and-downward  voice break.  The last note is slightly burry.  Take out that short middle note, and you’ve got a pretty close match to the mystery two-note song.

During this observation, I got the impression that the bird doing the wing-flashing was also the one producing the three-note song, but I couldn’t be entirely sure of that.  If I was mistaken, then it might have been the hidden bird, presumably a female, making the three-note song.  And that correlates with another clue hidden in the BNA account:

Female call is lower in volume, shorter, and slurred (Viers 1970).

No more details of female calls are mentioned, including whether they resemble the long song or the short song or both, or whether they may be given in response to the courtship displays of males.   We’re left with three possible explanations:

  1. The two- and three-note songs may be given by males in courtship.  However, the four-note short song is also clearly given in this context, among others, which would mean the two- and three-note versions might be individual variants of or perhaps excited versions of the short song.
  2. The two- and three-note songs may be the “Nest Coos” given by males.  However, both recordings I have of the shorter songs occur during duets, which is rather odd for a “Nest Coo.”
  3. The two- and three-note songs may be the female version of the short song, given primarily during courtship duets.  This contradicts my impression that the wing-flashing male in Mexico was the one singing the modified song, but I may have been wrong about that.

The Big Reveal

I promised you a mystery, not a solution.  I don’t know which of the three interpretations is correct.  That will take more data, probably more observations and more recordings.  It’s another terrific example of how little we know about the sounds of some common birds, and how difficult it can be to try to match the descriptions of earlier naturalists with one’s own recordings and observations.

It’s also a terrific testimony for the importance of behavioral notes on audio recordings.  Most of the amateur sound recordists I know don’t spend much time talking into their microphones at the end of each cut, but they should.  Talk about what the bird was doing while you’re still in the field, when you’ve just watched it happen, before you head home and forget the details.  Specific behavioral information is more important than any other type of information you record.

Above all, this is a demonstration of the way in which I answer my own questions about bird sounds — by trying to cross-reference field observations, recordings, the scientific literature, and my own intuition.  It can be frustrating to spend so much time researching a vocalization without being able to come to one solid answer.  But it’s also thrilling to be this close to the forefront of knowledge, just because I was willing to spend time trying to answer a simple question about a common bird.

The Gargling Chickadees

The Gargling Chickadees

Chestnut-backed Chickadee, Vancouver, BC, 11/20/2010. Photo by Sean McCann (Creative Commons 2.0).

What do chickadees sound like?  Why, everybody knows they say “chick-a-dee-dee-dee,” of course.

These “chick-a-dee-dee-dees” are what many people (and many books) describe as the “calls” — not to be confused with the “songs,” which are usually understood to be the high clear whistled tunes sung by males in a territorial mood:

All chickadee species give “chick-a-dee” calls, but only three of them — Black-capped, Carolina, and Mountain  — have whistled songs.  Since these three species are the most widespread and familiar North American chickadees, many people tend to judge other chickadees by their standard.  “Lacks whistled song,” many field guides say of Mexican, Chestnut-backed, Boreal, and Gray-headed Chickadees.  “No song,” say others, or simply “song unknown.”

But the many researchers who have studied chickadee vocalizations for decades might disagree.  As far back as 1981, Millicent Ficken pointed out that an often-overlooked chickadee vocalization called the gargle may actually fulfill more of the traditional “song” functions than the whistled songs.

Unlike whistled songs, gargles can be heard from all North American chickadee species.  Like traditional songs, gargles are learned; Ficken notes that captive Black-capped Chickadee hatchlings do not develop proper gargles in the absence of an adult tutor.   Individual birds typically produce several different types of gargles, forming a repertoire.  In most or all species, the gargles are given primarily by males and  associated with dominance establishment and territorial defense.  They are extremely complex, being made up of many different note types, often with trills and repeated motifs.

For all these reasons, in the species that don’t also whistle, the gargles can be considered “the song”:

Although some field guides may frame them as the outliers, the chickadee species above are not the unusual ones when it comes to the traditional song/call distinction.  It’s the whistling chickadees that are unusual, because they have two different kinds of songs — not only whistles, but gargles as well:

The whistling chickadees are a perfect example of how the original “song/call” distinction fails to hold up in many species.  Not only can the whistle and the gargle both be called “songs,” but even the “chick-a-dee” calls could be considered songs by some criteria.  We should always be suspicious of the many generalizations about birds that we draw from the most common, widespread, and familiar species — remember, they may be the unusual ones.


Rufous-collared Origins

Rufous-collared Origins

On May 8th, 2011, Andrew Davis of Winnipeg, Manitoba and his uncle, Tim Davis of Parker, Colorado, were stopped in the picturesque mountain hamlet of Georgetown, about an hour west of Denver, when they heard an odd whistled song that reminded Andrew of a Golden-crowned Sparrow.  He later wrote:

As we were tracking it down I remarked to Tim that what it really sounded like was Rufous-collared Sparrow, which I am familiar with from trips to Costa Rica and a trip last fall to Ecuador. Imagine our surprise, though, when that’s what it turned out to be!

Indeed, the two had found a Rufous-collared Sparrow, a common and winsome bird of mountain habitats from Chile to southern Mexico, the only tropical member of the familiar genus Zonotrichia.  Several thousand miles north of the species’ known breeding range, the Georgetown bird became something of a celebrity, and birders flocked to see it.

Rufous-collared Sparrow, Fortuna, Alajuela, Costa Rica, 2/9/2010. Photo by Steve Ryan (CC 2.0; click for link).

Naturally, many people wondered about the origin of the bird.  Some argued that because Rufous-collared Sparrows are popular as cage birds, the individual in Georgetown was likely an escapee from captivity; others held that the bird might well have arrived in Colorado under its own power.  Some in the latter crowd, I suspect, wanted to see Rufous-collared Sparrow added to the official Colorado state bird list; therefore they had a personal emotional investment in the notion that the bird might have flown to Colorado by itself.  Different people had different reasons for engaging in or avoiding this debate over origins; see Ted Floyd’s post on the ABA blog for a convincing argument that the bird is “worthy” regardless of its immigration status.

As a birder who appreciates the beauty and behavior of birds no matter when or where I find them, I agree with Ted.  However, I am also keenly interested in discovering the sparrow’s origins, not just to provide fodder for the natural-vs.-exotic debate, but because the answer is bound to be interesting from a biological perspective.  Is this an opportunity to learn about what happens when a bird’s migration mechanism fails catastrophically?  Or is it an opportunity to learn how a (formerly) caged bird can adapt to alien climates and communities?  Either way, it’s an opportunity.

Geographic origin

The first thing most people wanted to know was what part of the species’ vast range this individual sparrow had come from.  One line of thinking held that if it had arrived under its own power, it most likely came from the geographically nearest population in extreme southern Mexico — and, conversely, if the bird had originated in Mexico, it was more likely of natural origin.

Others argued that it should be the migratory tendencies of populations, rather than their geographic proximity to Colorado, that would provide the best evidence for a natural vagrant.  The populations in Mexico and Central America are non-migratory; in fact, they apparently hardly wander even a few kilometers from their breeding territories, making them very unlikely indeed to have sent a scout to the United States.  Populations in Chile and Argentina, however, are austral migrants — they breed in austral temperate zones during the southern hemisphere’s summer (our winter) and then migrate north, sometimes thousands of kilometers, when southern winter arrives.  Odd as it may seem, even though they are normally found many thousands of miles farther away, austral migrants are much more likely to fly to the United States than sedentary tropical birds.  For example, the majority of the 100+ Fork-tailed Flycatchers that have arrived in this country are of the subspecies that breeds in Patagonia, not the subspecies that breeds thousands of miles closer in central Mexico (though that one shows up in Texas sometimes).

In between the sedentary Central American populations and the austral migratory populations are a whole bunch of stay-at-home tropical mountain Rufous-collared Sparrows.  Most people interested in the Georgetown sparrow tended to agree that if it was found to come from a distant tropical area — say, Costa Rica or Ecuador — it was most likely an escaped cage bird.

Song sleuthing

When I heard reports that the Georgetown sparrow was singing loudly and often, I immediately wondered whether it might be possible to use its song dialects to pinpoint its birthplace.

Like its relative the White-crowned Sparrow, the Rufous-collared Sparrow in much of its range sings only a single songtype, and these songtypes vary regionally.  As it happens, Rufous-collared Sparrows have one of the best-studied songs of any bird species, and a great deal of that research has been done by Paul Handford of the University of Western Ontario.  In a 2005 article in Birding magazine, Paul laid out the evidence that different trill speeds at the ends of Rufous-collared Sparrow songs correpond to different habitats.  I thought that maybe, given the many spectrograms that he had published, in addition to the vast number of recordings of Rufous-collared Sparrows on Xeno-Canto, we might just be able to find a songtype that matched the Colorado bird.

I made a couple of trips to record the bird, and was able to get its voice on tape on two different days in June.  The first time I heard it, it was singing a three-note song without a trill:

Rufous-collared Sparrow song, Georgetown, CO, 6/15/2011.

Paul said this was typical of early-season breeding songs:

It was giving what we call ‘incomplete’ songs – ones lacking the terminal trill – which is usual for birds very early in the season, before the gonads have reached breeding size.

And indeed, a week later, I found the bird giving the same songtype with a somewhat extended terminal “trill.”  It’s pretty darn slow to be called a “trill,” but some populations of Rufous-crowned Sparrows give very slow trills like this, according to Paul’s research.

Rufous-collared Sparrow song, Georgetown, CO, 6/21/2011.

Paul found slow trills like this in some migratory populations in Argentina.  However, since even the “long” form of this song is quite short, it may simply be another version of the incomplete song.

Besides trill type, Paul indicated that repertoire size was the other key factor in trying to determine the bird’s origin:

If the bird is now producing two distinct song types then this suggests to me that the bird is of tropical origins since individual repertoires are only known to be well-represented in Ecuador; in south temperate and subtropical populations, individual repertoire size is one, as usual in Zonotrichia. In Ecuador on the other hand, individuals have been recorded with up to seven very distinctive song types!

Well, guess what?  A little later on my second visit, the Georgetown bird started belting out this song:

Rufous-collared Sparrow song, Georgetown, CO, 6/21/2011.

And then, a little later, this one:

Rufous-collared Sparrow song, Georgetown, CO, 6/21/2011.

Interestingly, the last songtype I recorded is the same as the one the bird is singing in the video that Connie Kogler took on May 19:

Conclusion?  The bird appears to be from an equatorial population with multiple songtypes, NOT a migratory austral population, nor a Central American population, as far as I can tell.  What does that mean for the likelihood that the bird got to Colorado by itself?  I’ll leave you to draw your own conclusions, but one thing is clear: careful listening (and recording!) is of tremendous help in solving mysteries like these.

— Update —

Got an email from Paul Handford in response to my post, with lots of great additional information.  Here’s what he wrote.  (Note that chingolo is the name of the Rufous-collared Sparrow in South America.)

Your second recording (the one following the ‘incomplete’) sounds like a bona fide complete ‘theme + trill’ to me. There’s several places that I have encountered songs with such ‘slow’ trills with only 3-4 trill elements, like this one. Nothing about it strikes me as weird or unusual.

On the other hand your third songs are out of my experience — they sound like nothing I have heard before. If I were to hear them in the field, my antennae would definitely waggle about thinking “sounds like maybe a chingolo there”, but they have a quality unknown to me. But then, there’s an entire continent of chingolo songs that I haven’t heard!

The fourth songs again have the quality of incompletes, but also are a bit weird.

All together, there’s only one song that sounds truly ‘kosher’ to me as a complete well-formed song (your second ones). What the 3rd and 4th songs mean is an open question to me: but they don’t impress me as necessarily fully-crystallized songs.

One thing you don’t mention in your discussion is that we can definitively rule out the longest-distance migrant populations, for these have very distinctive head plumage – they completely or effectively have lost the black head stripes (see attached for an in-hand comparison of birds netted in early spring at Lat ~26°S; the stripey one is a local bird and the grey-head is still on its way to the far south).

So my guess coincides with yours: it is a tropical latitude bird; further than that I don’t see us going — without DNA sequencing, at least.

A final thought: there’s a good chance that this is a first year bird; there’s evidence that even nominally single-song birds can continue to learn songs (i.e. there’s not a classic closed learning period) at least into their second year (and, as noted before, Ecuadorean birds can evidently learn over an extended period). All this raises the possibility that, rather than having as it were brought these three song ‘types’ with him, this little guy MIGHT be emulating something local in Georgetown. It seems clear (at least to me) that this bird is counter-singing with local white-crowns; maybe it is also interacting with other taxa? And maybe it learned other notes while it was perhaps living in a cage??

Fascinating possibilities.

Here’s the photo Paul sent with the email:

Rufous-collared Sparrows of the migratory (top, with gray head) and non-migratory populations (bottom, with striped head), near Tolombon, Salta, Argentina, 8/22/2004. Photo courtesy of Paul Handford
Subsong vs. Whisper Song

Subsong vs. Whisper Song

The American Robin frequently gives both subsongs and whisper songs. Photo by Mr. T in DC (Creative Commons 2.0).

Imagine a male robin, treetop in the early morning, belting out his song for all the world to hear, announcing his territory at the top of his avian lungs.  It’s an easy thing to imagine.  In fact, it’s pretty close to the stereotypical image of a singing bird.

Now picture that same male robin, deeper in the foliage this time, singing a song somewhat reminiscent of the usual treetop carol, but far, far quieter — so quiet, in fact, that it can’t be heard at 50 yards, and so subtle that the bird doesn’t even open its bill to sing, a slight fluttering of its throat the only clue to the source of the ventriloquial melody.

If you listen carefully to birds at close range, you’ll find that quiet, complex vocalizations like these are not uncommon.  Often, they are called “whisper songs.”  Some more technically-minded birders might call them “subsongs.”  Both subsongs and whisper songs are fascinating, but they are not the same thing.  Let’s look at the similarities and differences.


The term “subsong” has meant a number of different things since it was first coined in 1936, but I have generally thought of it as The Sound Approach described it:

Subsong…is usually given from dense cover, is often full of mimicry, and may bear little resemblance to familiar adult songs. […] Subsongs are typical of birds with a low sexual motivation, for example adults and first-year birds before the breeding season really gets started, or juveniles after it has finished.

In January and February, the flocks of American Robins that descend into the fruit trees around my home provide ample opportunities to hear and study subsong.  I have never made an attempt to age the birds I have recorded, so I can’t comment on whether the subsongs of juveniles and adults are different at this time of year.  (Intuitively, I believe that they should be different, since the avian brain changes as birds mature, but I have no evidence for this at present.)  What seems certain is that almost every robin in these flocks will sometimes get into the sub-singing mood:

American Robin subsong, Boulder, CO, 1/19/2008.

Compare the spectrogram above with the spectrograms of American Robin songs that I posted a few weeks ago, all of which were recorded in April, May, or June.   The January phrases appear more similar to “hisselies” than to “caroling” phrases, but they’re not a perfect match for either one.  Nor are they perfect matches for each other — they’re poorly stereotyped.  Add that to the extremely low volume, from a bird that doesn’t even open its bill, and you’ve got what appears to be a classic subsong — either the practice sounds of a juvenile that hasn’t yet learned to sing, or the “warmup” tunes of an adult whose neural song circuitry has atrophied over the winter, in the absence of breeding hormones.

The general theory about subsong is that the bird isn’t producing stereotyped phrases because it can’t — it either hasn’t learned how yet (as a juvenile) or it’s physiologically unprepared (as an adult outside breeding condition).  Like the babbling of infant humans, subsong provides a window into the process of vocal learning — a complicated, fascinating, messy process that, in a few short months, will result in the crisp, polished performances we know as adult song.

Whisper Song

The term “whisper song” has an even longer history than “subsong,” dating back at least to 1896, when Olive Thorne Miller wrote in the Atlantic Monthly:

A catbird at my back, too happy to be long still, would take courage and charm me with his wonderful whisper song, an ecstatic performance which should disarm the most prejudiced of his detractors.

The phrase appears to have crossed into the ornithological literature as early as 1914, with J. William Lloyd’s letter to Bird-lore titled “The Whisper-Song of the Catbird”:

The performance was like that of a bird in a reverie — like the ghost of a thought of a song. His throat merely trembled, and occasionally the bill parted just a trifle. Yet his song seemed the full repertoire of the Catbird.

Lloyd’s letter seems to have occasioned numerous other published observations of “whisper singing” in other bird species and at other times of year (e.g., Shafer 1916).  Quickly, the notion of a “whisper song” gained broad currency among people interested in birds — mostly, it seems, in reference to the same phenomenon we just described as subsong.

I prefer to restrict the term “whisper song” to another kind of quiet, complex vocalization — one that isn’t heard from juveniles or non-breeding adults, but rather from birds at a peak of sexual excitement.

American Robin courtship "whisper song," Mesa County, CO, 5/3/2011.

Note how different this whisper song is from the subsong above.  For one thing, it matches the “hissely” phrases we’ve seen from other spring robins.  The level of vocal control is much higher; the bird repeats patterns with precision.  For example, both the first and second phrases in the spectrogram include elements that are repeated exactly.  And the whole third and seventh phrases are carbon copies of one another.  This demonstrates that the bird is remembering particular phrases and re-deploying them at intervals, which means that these phrases form a repertoire, a library of remembered behaviors.  This robin isn’t “making it up” as he goes along.  He isn’t subsinging.  He’s singing.

The Sound Approach described such singing as “highly motivated, sexually charged, and ultra-crystallized,” typical of male birds in close-range courtship situations.  Indeed I have heard these whisper songs from male robins only during the breeding season, usually in the presence of females — and when no females were visible, I have suspected their presence.  This is an entirely different phenomenon than off-season subsong, and it needs a different name.  For now, “whisper song” seems like a good way to describe these complex, quiet vocalizations — the avian equivalent of whispering seductively into your sweetheart’s ear.