Folks,
If anyone could get a recording of that warbler,
the results could be very informative, for two reasons.
First, a single hybrid can teach us a lot about
the inherited part of the song. Nathan Pieplow and I
have a recent paper in Western Birds on the
unexpected pattern of singing by a hybrid Black x Eastern Phoebe. You can
download the paper from my website (see below).
Now, warblers, unlike flycatchers, learn their songs,
but all songbirds are thought to have an
inherited "template" that constrains what they can learn
and how the song is organized. Common
Yellowthroats typically repeat a rolling phrase 2 or 3 times, while
Macs typically giver 4-5 renditions of one
phrase-type, followed by 2-3 of a different type, but both phrase types are
at about the same pitch. The description of the
song doesn't match either of those patterns perfectly.
Looking at the song spectrographically, I might
be able to discern vestiges of one or both of the parental patterns.
Second, I seem to recall a Mac x Yellowthroat
hybrid in Oregon a few years ago that was recorded. I think I might
have that sound file stashed somewhere. It would
be really interesting to see if both sing the same way. That too could
tell us something about inherited constraints on song patterns.
So, someone please record that bird!
Thanks,
Arch McCallum
Eugene, OR

At 07:33 PM 7/1/2010, Paul Hicks wrote:
>Tweets, I once heard a ???typical???
>MacGillivray???s song from a grassy slope barely
>outside a moist meadow/pasture. Thinking this a
>strange location, I gave chase and discovered a
>C. Yellowthroat. I did not notice any unusual plumage pattern.
>-- Paul Hicks / Tenino, s. Thurston Co / phicks AT accessgrace.org
>--------
>
>The weird warbler we reported last Sunday at Duvall was most likely a
>MacGillivray???s Warbler x Common Yellowthroat hybrid. Steve Mlodinow reports
>that this hybrid has been described previously and that some had the white
>throat we observed. Dennis Paulson thinks it could have been that the female
>was MacGillivrays, the male the Yellowthroat, which might help account for
>the otherwise puzzling white throat. The song (which I was not able to
>record) could conceivably have been described as intermediate between the
>songs of these two species, though if it learned its song from nearby
>songsters it???s a puzzle what species those might have been. If anyone is in
>the area and would like to try to relocate it, the GPS coordinates are N
>47.73347, W 121.98959.
>"Eugene and Nancy Hunn" <enhunn323 AT comcast.net>
>_______________________________________________
>Tweeters mailing list
>Tweeters at u.washington.edu
>http://mailman2.u.washington.edu/mailman/listinfo/tweeters

D. Archibald McCallum, Ph.D.
Applied Bioacoustics
P. O. Box 51063
Eugene, OR 97405
phone 541 221 2112
www.appliedbioacoustics.com