I thought this was interesting and relative to Tweeters...
____________________________
Mike Smith
Univ. of Washington, Seattle
whimbrel at u.washington.edu

---------- Forwarded message ----------
Date: Sun, 22 Jan 1995 16:35:42 -0800
From: Richard Hoyer <hoyerr at CSOS.ORST.EDU>
To: Multiple recipients of list BIRDCHAT <BIRDCHAT at listserv.Arizona.EDU>
Subject: Hybrid Chickadee

Today, January 22, I saw what appeared to be a Black-capped X
Chestnut-backed Chickadee hybrid.
I had been hearing a couple Black-capped Chickadees for a minute or
so while doing a point-count and didn't pay much attention to them.
There were two, and when they came quite close to me, one with a very
brown back caught my eye. Luckily, it was near the end of the count at
this time, and I was able to watch it with my binoculars for a total of 4
minutes.
The color of it's entire back was dark reddish brown, like that
of a Chestnut-backed Chickadee. The sides and flanks were a striking
buffy orange, and the distribution of this color was the same as on the
Black-cap--a rather broad, even wash connecting across the vent and
undertail coverts. This was one of the two main characters that
separated it from Chestnut-backed.
The cap and throat were black, also in the same pattern as the
accompanying Black-cap, except the rear portion of the cap appeared to
have a brownish hint. The cap of the Black-capped Chickadee was pure black.
The face back to the auriculars was very white, and from the
auriculars to the mantle (i.e., the sides of the neck) was slightly
grayish. The breast and belly were white.
The wings were gray and the wing coverts and secondaries were pale
edged, the entire pattern closely matching that of the Black-cap. The
tail was the same color as well.
The few calls I heard were like Black-capped-chickadee, and
although it wasn't saying much (mostly "tsip" and "tee tee" contact
notes), it never uttered anything resembling Chestnut-backed (which is
unmistakable in itself). It never called the classic "chick-a-dee-dee",
which might have yielded some unusual quality. The behavior matched that
of the Black-cap.
Are there other records of this hybrid in existence?

The location of this was at Takenah Boat Landing along the
Willamette River just across from Albany, Oregon (in Benton Co.). The
habitat is riparian woodland, almost 100% Black Cottonwood with
undergrowth of willow and blackberry (both Himalaya and Creeping).
There are some Douglas-fir and Ponderosa (Willamette) Pine, but Chestnut-
backed Chickadees are almost exclusively restricted to large areas of
coniferous forest. Perhaps not coincedentally, in the last two falls I and
others noted an unusual invasion into largely deciduous ornamental
plantings in the residential areas of Corvallis. In the previous seven
years, I had only seen one away from their usual Corvallis haunt in the
Douglas-fir woods of Witham Hill in the nw. part of town.

With regards to the plumages of Golden-crowned Sparrow, I had no idea
that it was so complicated and poorly understood. I wish the field
guides would warn us of these kind of things! In any case, it can't be
as simple as adults molting into a plumage that resembles immatures,
because (I think) there are birds here all winter that look like adults
(there are now, at least). The birds I refer to as immatures *are*
quite variable, some with brown stripes where the black should be, and
some with no head stripes at all.
You're probably all thinking by now, "Rich must have his eyes
crossed, thinking he's seeing all these hybrids." It may be true, since
I've never seen this many hybrids in one season before (I also saw a
Brewer's Duck--Gadwall X Mallard--in December). Or maybe it's because
there are so few true rarities out there right now, I'm making this up
to make it look like I'm being productive. It's also possible that
David Sibley's article in _Birding_ this past summer has lodged itself in
my subconscious and I've unknowingly been seeking out hybrids ever since
then!


Rich Hoyer
Corvallis, OR
hoyerr at csos.orst.edu