Date: 3/15/17 10:14 am
From: Matt Webb <matthewmichaelwebb...>
Subject: Re: Allegheny County - Chickadees
Hey all,

This thread has, indeed, been very interesting to follow. For the past
four years, Bob Mulvihill and I have been banding chickadees (as part of
the Smithsonian Institute and National Aviary's Neighborhood Nestwatch
project) at numerous sites throughout the Pittsburgh region. We have long
talked about how we have been collecting data on these birds, and have the
ability to collect samples for genetic analysis, but we have not yet
pursued this...

At some sites over the four years, we've caught and banded birds that
measure/appear very much Black-capped, and the next year (and subsequent
years) we would only catch birds that measure/appear very much Carolina.
In the Pittsburgh region, the "hybrid zone" most likely covers our whole
area and measurement and appearance are not enough to go by, but I have
noticed that it is not as simple as saying "North of here, we'll only get
Black-capped..." etc. I've caught birds in some areas that appear and
measure very Black-capped, and then go several miles north of there the
next day and catch birds that only appear and measure Carolina. We do,
however, tend to see that birds in northerly parts of the region tend to
appear/measure Black-capped, and those in the south tend to appear/measure
Carolina, but it's never very clear.

When I say "measure", I'm referring to page 335 in Peter Pyle's 1997
Identification Guide to North American Birds. I recommend that birders
begin to carry this guide and a (small) wing rule when going into the field
to clear up any ID problems. I am, of course, kidding, but I just wanted
to say that even with the added ability to have the bird in-hand and
measure both wing and tail, there is no real clear "hybrid zone" line.

Also, to add an interesting note, just this past fall, we caught and banded
15 Carolina Chickadees at Powdermill Nature Reserve, the highest number
ever caught there. We have only sporadically caught and banded 1 or 2 a
year, if that, in the past.

Someone (hmmm...) should study this further!

Thanks and happy chickadee-ing,
Matt Webb
Carnegie Museum of Natural History
Pittsburgh, PA
 
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