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Band-winged Nightjar Feature

Band-winged Nightjar Feature

Band-winged Nightjar (subspecies decussatus), Rafan, Lambayeque, Peru. January 2010, copyright Christian Nunes

I’ll admit I was crushed when Nathan wrote a feature for xeno-canto before I did.  I have no one to blame but myself; it was pure laziness on my part that kept me from doing one.  After I got over the bruised ego from him being first I got my act in gear and wrote one of my own.  So if you want to read about the vocal variation in Band-winged Nightjars, check out my first xeno-canto feature.

Like Flycatchers and other suboscine passerines, Nightjars don’t learn their voices.  So distinct vocal variations may well have taxonomic implications.  In Band-winged Nightjar in particular there seems to be a good case for further study,  and potentially splitting the species.   For example, note how the differences in Whip-poor-will vocalizations recently played a role in the split of that species.

Finally, if any of you have recordings of Band-winged Nightjars you could upload to XC, especially of the decussatus, roraimae, or patagonicus subspecies that would be of great help!

Got Grosbeaks?

Got Grosbeaks?

If this is a common sight at your feeders, Aaron Haiman wants to hear from you. Ontario, Canada, 11/11/2007. Photo by Mike Mills (Creative Commons 3.0).

Aaron Haiman is a Master’s student in Tom Hahn’s lab at the University of California, Davis.  For his thesis research, Aaron is following up on the paper that Tom published with Kendra Sewall and Rodd Kelsey in 2004, the one that described five call types of Evening Grosbeak.

As you will recall, Joseph Grinnell in 1917 recognized five subspecies of Evening Grosbeak on the basis of plumage brightness and bill morphology.  In 1974, the American Ornithologists’ Union decided that some of these subspecies were not distinctive enough, and so they lumped them into the three subspecies currently recognized.  However, the five call variants described by Sewall et al. match up quite well geographically with Grinnell’s original five subspecies.  So Aaron is setting out to determine whether Grinnell’s original taxonomy should be reinstated.  Eventually, he wants to answer lots of interesting questions:

  • do birds of different call types look any different from one another?
  • have they diverged genetically?
  • do other vocalizations vary along with the flight calls?
  • do they have different habitat requirements?
  • do they prefer different foods?
  • do birds of one type respond to the flight calls of other types?

In order to answer all these questions, Aaron needs grosbeaks.  And a great place to find themis at backyard bird feeders.  Aaron has already visited the properties of eight homeowners in three states who reported Evening Grosbeaks at their feeders, and with their generous cooperation, he has set up nets to capture the birds.

Once he captures a grosbeak, Aaron measures it, bands it, takes a sample of its blood, and releases it back into the wild.  Of course, he also audio records the bird’s flight call.  On his recent trip to Colorado, Aaron banded 19 Evening Grosbeaks — which isn’t a bad haul, but much more data is necessary to unravel the mysteries of the biology of this remarkable nomadic finch.

If Evening Grosbeak is a regular visitor to your backyard, and you are willing to host a banding and recording session, please  e-mail Aaron at describing where you live and how many Evening Grosbeaks are coming to your feeders.  So far, Aaron has gotten wonderful support from several generous people willing to open their yards to his research — and if you’re willing and able to help, he would love to hear from you.

Automatic Song Recognition Online

Automatic Song Recognition Online

Hermann Redies and the folks at Xeno-Canto have just launched an ambitious project called Pai-Luiz, which attempts to automatically identify recordings of unknown bird sounds by looking through the entire Xeno-Canto database for matching syllables.  It’s just a prototype system at the moment — not particularly user-friendly yet, nor particularly accurate, but it still represents a huge leap forward in online automatic sound identification.

To give Pai-Luiz a try, you have to log in as a Xeno-Canto user, upload two different WAV files of the sound, and specify a precise bandwidth — as Hermann explains in the online documentation, you need to be pretty familiar with sound editing and spectrograms in order to do all this.  Once you upload a sound, Pai-Luiz takes up to an hour to process your request and email you a long list of recordings that might match yours.  The list is only a group of best-guess suggestions and there’s no guarantee that it contains a match — the actual identification still falls to you, the human user.  But when it works correctly, Pai-Luiz cuts down a lot on your workload — instead of having to listen to tens of thousands of recordings, you only have to sort through a few dozen possible matches.

Hermann is looking for users to try out the system and give feedback so that he can improve it.  If you’ve got a little extra time, you might want to feed it some known and unknown sounds to see what it kicks back.

(By the way: Hermann is a co-founder of Association “Mãe-da-Lua”, which purchased a Nature Reserve for the birds of the threatened caatinga habitat in northeastern Brazil, but can no longer afford to keep it open.  The reserve is looking for buyers or donors; for more information, see Hermann’s website.)

The Coolest Bird

The Coolest Bird

The Coolest Bird, by Rich Levad. Click for link

I’ve posted a couple of times before [1 2] about the Black Swift, one of the most unique and mysterious birds in North America, but this news was too good not to report: Rich Levad’s book “The Coolest Bird” has been published online by the American Birding Association.  Click the link for the 152-page PDF.

I had the privilege of knowing Rich before his untimely death in February 2008 from ALS (also known as Lou Gehrig’s disease).  He was such a force of nature that even though his career as an amateur ornithologist didn’t begin until after he retired from teaching, he still managed to move our knowledge of the Black Swift forward as much as any other individual in the past three decades.  “The Coolest Bird” is part memoir, part historical narrative, part monograph.  Rich meant it to be a book for the masses — the story not only of the bird but of all those who have pursued it, including their rivalries and prejudices, their flashes of insight, their daring climbs to nest locations, and above all their passion for the bird.  It’s a fast and absorbing read — if you have any time to spare, I highly recommend it.

The Changes Are In

The Changes Are In

It’s July, and that means it’s time for the annual update to the American Ornithologists’ Union Checklist.  That means the splits I blogged about recently are now official.

Besides the high-profile splits of Winter Wren, Whip-poor-will, and Black Scoter, the checklist committee also did some major rearranging of scientific names, splitting a number of genera and reassigning several species to a new genus.  They do this whenever scientific studies (usually DNA studies these days) make it clear that birds currently classified in the same genus are not, in fact, each other’s closest relatives.  Although most such splits this time around were based on DNA evidence, vocalizations also support most splits.  Below we’ll take a quick survey of what’s changed and how audio was involved.

Species split

  1. Winter Wren is split into three species: Pacific Wren (Troglodytes pacificus) in northwestern North America; Winter Wren (Troglodytes hiemalis) in eastern North America; and Eurasian Wren (Troglodytes troglodytes) in the Old World.  Vocal differences were important in this split; see my older posts on how to separate Pacific from Winter Wrens by song and call.
  2. Whip-poor-will is split into Mexican Whip-poor-will (Caprimulgus arizonae) and Eastern Whip-poor-will (Caprimulgus vociferus). Vocal differences were important here as well; see my earlier post on this topic.
  3. Black Scoter is split into Black Scoter (Melanitta americana) in the New World and Common Scoter (Melanitta nigra) in the Old World.  Once again vocal differences were key, and once again you can hear them in an earlier post.

A couple of Latin American trogon species, the Greater Antillean Oriole, and the Elepaio of the Hawaiian islands were also split.

Changes in Genus

“Brown” Towhees Move to Melozone

Abert’s, Canyon, California, and White-throated Towhees will move from the genus Pipilo to Melozone, where they will join the Rusty-crowned, White-eared, and Prevost’s Ground-Sparrows. This genus split makes sense when you listen to the songs: the “brown” towhees sing with unmusical high-pitched trills and squeals that are very different from the rich, musical series of the “true” towhees.

“True” Towhees Remain in Pipilo


These species usually sing songs composed of 2-4 series of fairly musical notes — sometimes highly musical notes.  Some of them can be confused with each other, but rarely would they be confused with any of the “brown” towhee songs.

“Nashville” Warbler complex moves to Oreothlypis

Nashville, Virginia’s, Lucy’s, and Colima Warblers will move to the new genus Oreothlypis, along with the Orange-crowned and Tennessee Warblers.  This group is characterized by songs that are composed of 1-3 rapid (but not buzzy) trills.  The similarities are obvious on the spectrograms and to the ear:

Blue-winged and Golden-winged Warblers remain in Vermivora

These two species, plus their extinct relative the Bachman’s Warbler, remain in Vermivora.  All three are linked vocally by their very buzzy songs, quite similar to one another but quite different from those of the species leaving the genus.

Bachman’s Warbler songs can be heard at the Macaulay Library: [1 2]

Crescent-chested and Flame-throated Warblers move to Oreothlypis

This is one change that doesn’t seem to be supported by vocalizations.  These two Central American species were formerly in the genus Parula with (surprise) the parulas.  And their songs sound very like those species — high and buzzy — not at all like the songs of the other bird moved to Oreothlypis.

These embedded iframes are great, but they take up a lot of space, so we’ll continue on this theme tomorrow.

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Swift Travels

Swift Travels

Where they go, nobody knows: The migration routes and wintering grounds of Black Swifts remain a mystery. Photo composite by Bill Schmoker, Zapata Falls, Colorado, June 2008 (click for link).

Last fall I posted about the project to put geolocators on Black Swifts in an effort to determine, for the first time, where the species spends the months from October to May.  I just got exciting news from Rocky Mountain Bird Observatory’s Jason Beason: on Wednesday night, the team succeeded in recapturing one of the birds wearing a geolocator!

Of course, this success will take a while to bear fruit.  First Jason has to hang the geolocator outside his house for a week so that it can be calibrated according to the sunrise and sunset times at a known location.  (All the geolocators were also calibrated in this way prior to deployment.)  Then, assuming that all has gone well with the device over a year of riding swiftback, the team can download the data and begin the complex task of determining the latitude and longitude of the device every day for the past year based on sunrise and sunset times.  Then, and only then, will the team be able to generate a map of the bird’s travels.

Only four geolocators were placed on swifts last year: three at a cave in the Flat Tops Wilderness and one at a nest at Box Canyon Falls in Ouray.  The geolocator recovered on Wednesday came from the Flat Tops cave. To have recaptured one of only three marked birds there is a tremendous success, but a calculated one, since Black Swifts have tremendously high site fidelity from year to year.  Jason and his collaborators (Kim Potter, Carolyn Gunn, Chuck Reichert, and Todd Patrick) will revisit the cave next month to try to snag one or both of the remaining geolocators at that site, and they will be attempting to recapture the Box Canyon bird tomorrow–it is believed to be attending the same nest as last year.

Thanks and congratulations to the intrepid explorers who are on the verge of solving one of the biggest remaining mysteries of North American bird migration!

A Sonoran Sampler

A Sonoran Sampler

One of the most spectacular birds in Mexico, Elegant Euphonias were common at our high camp at Rancho Santa Barbara. Photo by Jerry Oldenettel (Creative Commons 2.0).

Well, I’m back from two weeks in southern Sonora, recording bird sounds with an expedition led by the Sonoran Joint Venture and Western Field Ornithologists in the Sierra de Alamos / Rio Cuchujaqui Wildlife Protection Area.  It was a fantastic trip; I got 10 lifers and accumulated 19 hours of audio to sift through.  It’ll be great blog fodder once I catalog it all.  In the meantime, I’m still struggling to crawl out from under the massive pile of Things To Do Now That I’m Stateside, so I thought I’d just share with you a quick sample of some of the more interesting audio moments from the expedition.

Here’s the sound of a female Rose-throated Becard seizing a cicada, beating it against a tree limb until it quits stridulating, and then consuming it.

Here’s a large colony of bats squeaking in their daytime roost in the skirt of dead fronds below the crown of a palm tree.

If I were to judge a birdsong contest in Northwest Mexico, I’d have to give a prize to Sinaloa Wren, whose contributions to the soundscape were rich and frequent.

But I also love the sweet, soft, musical song of the Rufous-bellied Chachalaca.

No Mexican audio sampler is complete without this bird sound (in fact, much of a recordist’s time in Mexico is spent trying to get away from this species):

Near the El Cajon camp, an adult Gray Hawk fed two young at a nest right above my head:

And here’s the grand finale: the sound of a small group of Black-throated Magpie-Jays driving a Laughing Falcon off his perch.  He isn’t laughing about it, but if you listen closely, you can hear a couple of his faint chuckles.

In the coming weeks, look for some blog posts with a decidedly southwestern flavor!  It’s good to be home.

Off to the Tropics!

Off to the Tropics!

There’s going to be a brief hiatus around here, as both of your Earbloggers are headed south of the border for a little while.  Andrew Spencer is currently in Colombia, and I’m about to leave for two weeks of recording in Mexico.  However, Andrew did promise one blog post from the road sometime in the second half of June.  Other than that, I’ll be back online around the 4th of July, hopefully with lots of new insights into bird sounds!

In the meantime, if there’s nothing new to read here, I recommend getting out into the field and listening to (maybe even recording) some animal sounds!

Boat-billed Flycatcher Feature

Boat-billed Flycatcher Feature

Boat-billed Flycatcher, Horto Florestal de São Paulo, Brazil. Photo by Dario Sanches (Creative Commons 2.0). Click for link.

I just published my first feature article for Xeno-Canto.  I figured I should give their blogging functionality a try, and I’m happy with the result.  My subject is geographic differences in the vocalizations of the Boat-billed Flycatcher (Megarynchus pitangua), a Central and South American species that looks much like the Great Kiskadee of south Texas.

For reasons I explained in my recent post on hybrid flycatchers, vocal differences in flycatchers are likely to represent strong genetic differences.  I noticed some time ago that Boat-billed Flycatchers in Central America make some distinctive sounds that Boat-billed Flycatchers in South America don’t make, and vice versa.  I thought I would be able to write a quick feature recommending a split — a la my Gray Hawk posts [1 2] — but as I started writing, I realized that Boat-billed Flycatchers make a number of different sounds, some of them geographically variable, others apparently not.  It took me far longer to complete my project than I anticipated, which is one of the reasons why you’ve seen Earbirding go so long without a new post!

So head on over to Xeno-Canto’s feature page to check out my work.  As always, I’d love to hear what you think!

Back on the Air!

Back on the Air!

Wrong sense of the word "hack," unfortunately. Photo by Angus Kirk (Creative Commons 2.0).

Apologies to all of you who have been trying to access the site for the past 5 days — Earbirding got hacked.  (It was my own fault for not updating my installation of WordPress on a regular basis.  Those of you who run WordPress blogs, let this be a lesson — always update on schedule!)  As far as I can tell, the hack was only of a spam-link nature and it didn’t destroy any content — nor did it harm any visitor computers, as far as I know.

Most of the site is back online as of this morning, but certain links, iframes, etcetera may remain broken.  If you find anything that isn’t working, please let me know.

Meanwhile, classes have ended for the semester and I’m now in the grading morass, but at least it’s a self-scheduled morass, and I hope to be bringing you some fine new content soon: upcoming blog topics include hybrid birds, hearing loss, Whip-poor-wills, Warbling Vireos, and annoying spectrograms.