Wednesday, August 27, 2008

Flight Call Identification: Veery

This is the first in a series of posts presenting flight calls of nocturnal migrant birds. If you haven't yet, you might want to refer to my introduction to flight calls before, or after, reading this account.

The Veery (Catharus fuscescens) spends its summer in damp, deciduous forests, stretching in a loose band across North America. The song is familiar, often used as an example of the dual syrinx, its downward-spiraling flute-like notes a marvel of nature. Because winters are spent in central and southern Brazil their migration should cover the eastern two-thirds of the U.S., though eBird shows show reports are spotty across the Great Plains. Perhaps this is more likely a testament to the number of observers and the number of Veeries seen during migration. Flight call monitoring might provide a more accurate assessment of where the birds are migrating.


Veery reports according to eBird (map created 28 Aug 2008).
How many of the blank areas are simply "fly over" regions?


Edited to clarify the map: The above map displays all reports throughout the year, both on the breeding areas and on migration. For example, the light green wash (indicating relatively fewer sightings) across the gulf-coast states are migratory observations, the dark green wash across the southern provinces and northern U.S. are sightings from the breeding ground. Dark green indicates high frequency of reports, likely due to repeated observations on breeding territories. Light green, or areas of infrequent observations, are due to the passing nature of the Veery in these areas.

For life history information about the Veery, including listening and viewing the song, visit the All About Birds web site.

Timing-wise the best time to listen in the northern U.S. is now. According the the Birds of North America Online peak migration in New York runs from late August to early September, in Minnesota 31 August is an average peak date. Southern birders have a couple weeks: in Louisiana migration peaks between 15 - 30 September.

Like the other Catharus thrushes, Veery flight calls are relatively low in frequency (pitch) and are relatively long. The call I'm highlighting here, freely available online through the Macaulay Library online archives, is about a quarter-second long (250 milliseconds). I find the thrushes a bit easier to hone in on than the even-quicker warbler and sparrow flight calls.

The Y-axis shows frequency in kiloHertz (kHz), which you can think of this way: the higher the kHz, the higher the pitch of the sound. Johnny Cash sang at low frequencies, Tiny Tim at high frequencies. Annoyingly high frequencies.

Looking at this call we see the Veery's flight call is relatively linear, typically keeping within 2.5 - 2.0 kHz. The frequency usually declines during the length of the call, which is why the pitch falls when you hear it though the heavily-modulated ending may slightly rise. This call shows up very dark and bold, indicating it's pretty loud. The bird must have been close to the microphone when recorded.

video

Veery flight-call, full speed.

Pretty fast, right? It's intimidating to think this is one of the longer flight calls. Examining the spectrogram shows this call starts pure, the note is slightly-descending but the line is flat, not wavering (modulated). The end of the call is heavily modulated, though, rising and falling very quickly, which gives a distinct "burry" sound.

Listen to the same call at quarter speed, it's easier to hear those characteristics: descending in pitch but unwavering, then fluttering rapidly through the modulated end of the call.

video

Veery flight-call, quarter speed. Listen to the
descent in pitch, then the fluttery, modulated ending.

Try listening to the quarter-speed version a few times, and once you clearly hear the characteristics try listening to the following clip, the same call at half speed. Can you still hear the characteristics?

video

Veery flight-call, half speed.

Again, listen to the half-speed version a few times, and once you're comfortably hearing the characteristics at this speed, scroll back up and listen to the full-speed version.

Of course, this is one call of a single individual, and I've mentioned you're bound to encounter variation. That's especially true in Veeries. Oftentimes the Veery's entire call is modulated, though the heaviest modulation tends to be towards the end of the call, like this one. This call could be confused with the other thrushes (Hermit, Wood, Swainson's, Gray-cheeked, Bicknell's; even bluebirds and robins) as well as other species that give thrush-like calls, meaning relatively long and in the lower frequencies. These include tanagers, meadowlarks, and orioles.

For more Veery recordings and spectrograms visit Call Notes & Flight Calls.

  • Veery flight call recorded by Bill Evans, 24 April 1990 in Alabama, U.S.
  • Recording courtesy of Macaulay Library, Cornell Lab of Ornithology.
  • Spectrogram created in Raven Pro, Bioacoustics Research Program, Cornell Lab of Ornithology.
  • For more information about the Veery visit All About Birds.

4 comments:

N8 said...

1- I flipped through my field guide trying to figure that map out, not thinking that it might only be a summer range. Tricksy, CLO...

2- The Veery at a quarter speed sounds like a whale song.

Cool stuff. I wish i were better at night calls.

noflickster said...

n8 - Sorry for any confusion, I should have clarified that the map covered all months, or both breeding and migration sightings (wintering area is off this map). I edited the text to reflect that, hopefully it's a bit clearer.

Maybe we're spoiled in the Ithaca area, but it seems more and more folks are engaging in "radar ornithology," checking the radar to "see" migration, then determining when/where to bird the next morning. Hopefully that will translate to more and more folks standing outside somewhere and listening and (with time, practice, and a lot of patience) starting to identify the various notes. Even better, build a microphone, record "your" birds, and analyze the recording to learn those sounds.

As I mentioned, even if you don't identify a thing it's still awesome to hear the diversity and number of birds overhead!
-Mike

jan m said...

I find this so fascinating. As much as I love birding, I rarely think of them flying overhead at night. I'm glad that there is always something more to learn.
Thank you for your well-wishes. I'm getting there slowly, and looking forward to more birding before I have to return to work.

noflickster said...

Hi jan m - I think that's part of why flight calls are so exciting, they give a window into a phenomenon that flows by mostly unnoticed. Glad you're doing well, take it easy and enjoy the birds!
-Mike

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