On Tue, 26 May 1998, Michael Price wrote:

>
> Hey, ya wanna hear variation in warbler song, listen to a migrant wave of
> male Yellow Warblers D. petechia: in the fallout yesterday, Bev Gordon, Mike
> Beck and myself heard six variant YEWA songs, minimum: if only the little
> demons didn't sound so much like redstarts half the time.
[snip]
>
> Michael Price A brave world, Sir,
> Vancouver BC Canada full of religion, knavery, and change;
> mprice at mindlink.net we shall shortly see better days.
> Aphra Behn (1640-1689)

Or get up at 4 a.m.

If you catch them at the right time of day (dawn chorus) or in the right
context (dispute with a neighboring male) an individual Yellow Warbler may
choose to use all of its dozen or more differing songtypes. That's right,
each individual has that many distinct songtypes. For most of each day
when a male is mated (which is most of the time), a male will stick to one
song pretty much exclusively, and within an area, most males have similar
common, or "type 1" songs, so it's easy to be fooled into thinking you
know everything about the songs of local Yellow Warblers, when in fact you
only know 8% or so of what they can do. So keep in mind that just because
you're hearing variants during migration doesn't mean that you're hearing
regional variation or dialects - you may just be getting a larger sample
of each bird's repertoire than usual. Of course, there is some geographic
variation as well...

As for the Yellow Warbler/American Redstart duo, one characteristic I used
during my summer surveying breeding birds in Maine (warbler heaven,
everyone should go sometime) was the more emphatic or explosive quality to
the Redstart song. That and familiarity with about three or four
representative songtypes from listening to a tape, and I got through the
summer without ever mistaking one for the other (and yes, I did check
visually every chance I got). Oh, now another detail is coming back - the
tricky YEWA songs are the ones that end with a downward sweep - "sweet
sweet sweet sweet tyew", instead of with the usual upsweep: "sweet sweet
I'm so very sweet." But the "tyew" ending a YEWA song is never strongly
accented; the downward sweep ending most AMRE songs always is.

As an aside, It was a real lesson in how much you can learn from listening
to tapes. Paul Adamus (now in Oregon, I gather) made an excellent
"tutorial" tape of all the expected birds in the northern woods (about
100 species, including a couple dozen warblers). The tape was narrated,
pointing out some of the consistent differences between species. To get
the job, I had to pass a test, ID'ing those same recordings (without
narration!), and a passing score had to be better than 93% correct. I
flunked the test, went home inspired by my failure, and listened to that
tape for probably 100 cumulative hours, until I could tell what species
was coming up strictly by background noise. On the second try, I passed
with a record score, and in fact found an error on their test key.

But back to the point of the story, I *never* expected the "tape learning"
to translate perfectly to the field - I learned the practice tape somewhat
cynically, knowing the test would be made up of the same exact cuts that
were on the practice tape. I fully expected to have to relearn the birds
"for real" once I got up to Maine. But it never happened. Over and over
and over again, I would check up on a tricky song (e.g. Yellow vs.
Redstart, Chestnut-sided [unaccented variant] vs. Yellow, weird variants
of Blackburnian Warbler and Bay-breasted...). And 100% of the time I was
right on the first guess.

I guess the "Birding by Ear" tapes tried to do for the general public what
Paul's tape did for me. I haven't listened to them, but gather that they
do the same thing as Paul's practice tape on a simpler level. If so,
there's probably still a market niche open for a thorough, "expert"
version.

Christopher E. Hill
Department of Zoology
University of Washington
P. O. Box 351800
Seattle, WA 98195-1800