[Va-bird] More "Northern" Black-capped Chickadee comments and a Redpoll at a Warren County feeder

From: "ROB SIMPSON" <RSIMPSON@xxxxxxxx>
To: <va-bird@xxxxxxxxxxxxx>
Date: Tue, 11 Dec 2007 22:00:49 -0500

One of our colleagues from Warren County report a redpoll (they think common
redpoll) has been coming to their feeder irregularly for the past week. It is
on a gated community. Hopefully we will have more down the road.

Much of the discussion about BCCH has been about Gene Sattler's (et. al.)
excellent paper on Chickadee hybridization. Since there still seems to be a
bit of confusion I would like to emphasize two things. Gene's study did not
include the use of visual field marks for identifying hybrids or parental
species. I think Dave might have read the abstract and misinterpreted the
intent of the paper.  Their study involved the measurements we use in bird
banding (wing cord, tail length, weight) to help separate the two species.
Years ago, at a SNP symposium I believe, I mentioned to one of the
researchers how it would be great to have a repeat study to see how
accurately hybrids could be determined with visible field marks.

Second and most importantly the BCCH invasion this year is of the bright very
contrasty Northern subspecies which only comes down infrequently and does not
hang around to promiscuously exchange its genes in the summer. These birds
are readily separable in the field from our Carolina Chickadees. They are
also usually separable from the Appalachian subspecies of Black-capped
Chickadee. In my experience if you live in the valley you will have a tough
time finding any hybrid looking individuals or Appalachian BCCH.  If your
bird looks like a Carolina don't be afraid of calling it a Carolina
Chickadee. If the BCCH genes are not expressed in it's field morphology it is
probably mostly a Carolina, even if it has some left over remnants of an
unholy BCCH matrimony in the distant past. If you are observing chickadees
with bright white hockey sticks on their wings (greater coverts and primaries
heavily edged in white to appear like a hockey stick), bold white solid cheek
patches that do not blend into dusky grey in the rear, rectrices heavily
edged in white you are looking at good pure "Northern / Canadian"
Black-capped Chickadees. If you live in a hybrid zone of Carolina and
Appalachian BCCH try to pick out the hybrids (the Northern BCCH will still
stand out).

There are over twice as many named orchid hybrids than good diploid species.
One human induced hybrid involved seven different genera. Waterfowl can
almost show a continuum if you start looking at the hybrids involved. I
believe I read once that there are more described hybrids of waterfowl than
named species. Mallards are very promiscuous mixing it up with whomever.
Swans have seduced mergansers and all swans of the world have messed around
at least in captivity. Bill Sladen has a famous Mumpling three way hybrid
(Trumpeter x Whistling x Mute).  If you really took this to heart and worried
that there may be introgression in any waterfowl you observed one might be
persuaded to call any duck, goose or swan, simply a waterfowl.  Red
Crossbills have hybridized with Pine Siskins and Common Redpolls with Pine
Siskins and most warblers have stepped over the species line more than once,
think of this as normal but exciting and not exasperating. I did a paper in
graduate school on Gull evolution - this group really presents some
interesting combinations.

I have had the opportunity to be involved with the study of, discovery of and
naming of quite a few hybrid organisms mostly in plants, amphibians, fish and
birds. Although my graduate work was in ornithology I worked a lot with the
late Prof. Wagner at the U. of Michigan on fern hybrids. You will soon
realize how frequent hybrids are once you start looking for them (30% of our
eastern ferns have a hybrid origin). Wagner was the one who did the pioneer
studies in showing how reticulate evolution was a major force in fern
evolution. Another thing you soon realize is you can identify most early
generation hybrids in the field. You of course have to know the parents
intimately.  I urge all compilers to alert their teams to try to identify
every Chickadee. I periodically take specimens from our college collection
(of both chickadees) to the compilations to help people get a search image
for the two species. In years past when we had major invasions of northern
BCCH I believe they were very under reported or not reported at all on many
Valley / Mountain Virginia CBC counts. This is a major invasion year. If you
are in the Shenandoah Valley / Mountains you should be seeing big bright
chickadees like you have not had at your feeders in a decade.  Dave if I
remember correctly you live at a low elevation along Cedar Creek and probably
would not be plagued by many or any F1 hybrids (vs. if you lived up on North
Mountain). I have some very active field biology students who would be glad
to help you get confidence in separating the species when you are at your
home away from home.  The race of the Carolina chickadee that occurs in se VA
is even smaller and less well defined than our Shenandoah lot. If a northern
BCCH makes it down to se VA territory it will really stand out - this is the
year when we might get a few on the coastal plain. I would really like to
know how far down the Appalachians the Northern BCCHs are traveling. Also if
you are in an area of Appalachian BCCH  (Highland County ...) see if you can
tell the resident BCCH race from the northern invaders.

Another question: do any of the resident Appalachian BCCH (or hybrids) head
down the slopes into the valley areas during invasion years of Northern BCCH.
If anyone gets any clues to these patterns please email me off line. Thanks
to the several people who have emailed me their chickadee reports already.

I started my Chickadee studies in Canada at the age of 12 when I decided I
would discover Canada's 1st record of a Carolina Chickadee. I looked at every
Chickadee trying to make it into a Carolina - I am still looking at every
chickadee.

I have been way to busy to do any banding of the chickadees this fall and
apologize for not getting back to you sooner with additional comments. Ann
and I wrote and illustrated 3 books in 2006. We are trying to do four this
year and with Dec. 31 nearby we will not be successful.  Good Chickadee
hunting on the CBCs - Rob Simpson

Robert C. Simpson

Associate Professor of Natural Resources

Program Contact for Natural Resources Focus in the Science Degree

Program Contact for Outdoor and Nature Photography Careers Certificate

Contact for information on: Field Biology, General Ecology, Wildlife and
Fisheries, Habitat and Food Plant Identification, Special Studies in Wildlife
Field Techniques, Birds, Mammals, Reptiles, Amphibians, Fish, Mushrooms
Edible and Otherwise, Plants and Nature Photography.

Email:   rsimpson@xxxxxxxx

Course websites:  http://www.lfcc.edu/classes/simpson/

Phone: 540 868 7206

Fax: 540 868 7100

[Va-bird] More "Northern" Black-capped Chickadee comments and a Redpoll at a Warren County feeder

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