Hi folks,
I saw the following exchange on the "Frontiers of Bird Identification" list,
and thought that, since there's been some interest in Northwest vs American
crow taxonomy on this list, some of the Tweeters and OBOLoids might be
interested. Alvaro Jaramillo had some comments on his observations of
Oregon coastal and inland crows, as well
Now, to go "tick" a California Raven.....
Jon. Anderson
Olympia, Washington
festuca at olywa.net
--------------------- Cross-Posted Messages --------------------------------
Subject: [BIRDWG01] California Ravens
Ken Able <kpa at CSC.ALBANY.EDU>
Date: Thu, 21 Sep 2000 16:28:08 -0400
A paper on raven genetics and phylogeny by Kevin Omland will appear in
one of the next few issues of Proceedings of the Royal Society, B (for
Biological Sciences). What he has found, examining mtDNA, is that there
is a deep genetic split between California Common Ravens and Common
Ravens from elsewhere in North America. The data suggest a divergence
of as much as 2 million years. Ravens from all other parts of North
America are more similar to Old World Common Ravens than they are to
California birds. The two "forms" are sympatric in the Pacific
Northwest where the degree of interbreeding is unknown. Otherwise, the
California and other Common Ravens are at least apparently identical.
This has the makings of a hideous field problem. Has anyone noticed
anything distinctive about California Common Ravens that might reflect
the apparent considerable genetic difference?
--
Kenneth P. Able, Professor
Department of Biological Sciences
University at Albany, SUNY
1400 Washington Avenue
Albany, New York 12222
Phone: 518-442-4330
Fax: 518-442-4767
Email: kpa at csc.albany.edu
---------------------- Second Forwarded Message ---------------------
Subject: Re: [BIRDWG01] California Ravens
Alvaro Jaramillo <alvaro at SIRIUS.COM>
Date: Thu, 21 Sep 2000 17:00:49 -0700
At 04:28 PM 9/21/00 -0400, Ken Able wrote:
>A paper on raven genetics and phylogeny by Kevin Omland will appear in
>one of the next few issues of Proceedings of the Royal Society, B ...
>
Interesting stuff, particularly since I have been thinking about
crows/ravens a bunch lately. I live with these California Ravens, seeing
them pretty well every day from my place. Yet I grew up in Canada where the
other raven is found. It has always struck me that the ravens here are just
not the same as the ravens up north. Part of it is the size, the California
birds do not instill the same impressive "jizz" as the others do. In some
ways, the California ravens are more crow like, but of course this is
extremely subjective. The flock sizes appear to be average larger here in
California. But, I think that vocalizations should be studied. While
California ravens sound like ravens and not crows, Chihuahuan ravens sound
like ravens too, in fact I find that telling ravens apart by voice in
Arizona takes quite a bit of experience. Its not trivial. I bet there are
vocal differences between the two Common Raven populations. Personally, I
think I have detected differences but have never systematically thought
about it, a systematic approach will be needed to figure this out. The
differences are probably in the little details, particularly in the average
higher frequency (pitch) of raven calls in California. Also there are some
calls which I have heard from northern ravens which I have yet to hear in
California. One of my favourite calls of 'northern' ravens was a popping
sound which could really throw you for a loop when you heard it. If it is
present in California ravens its a rare vocalization as I have yet to hear
it here. Some of the weird gurgles and wacky noises that Canadian Ravens
give (can't describe them well in text, sorry) appear to be lacking in the
repertoire of California ravens. However, I don't know how local or
widespread these vocalizations are in 'northern' ravens.
Another species which is worth looking at is the American Crow. Having just
spent two weeks in Oregon it was amazing to see how different the coastal
American Crows appeared from the interior (east of the Cascades) American
Crows. The coastal guys are puny, with tiny bills. Coastal birds were in
heavy body moult during early-mid September while the interior birds
appeared to be further along in the moult (lots of patchy brown and black
birds on the coast, interior birds more evenly black). Also, they have
weaker calls that differ in pitch from those of the eastern birds. While
hybridization with Northwestern Crows could be blamed for the small size of
these coastal birds, its odd that they would have a higher pitched call as
NW crows tend to be lower pitched than American Crows. I gather that corvid
vocalizations are learnt, right? Behaviourally, coastal Oregon crows were
much tamer than interior crows, they also were commonly found foraging
along seashores similarly to the Northwestern Crows. In this part of
California (San Mateo County) American Crows are not found along the coast,
and they certainly do not feed at the tide line. The similarities and
differences between west slope American Crows and NW Crows versus interior
American Crows seems a problem ripe for study through newer molecular
techniques.
And how about them Woodhouse's Scrub Jays.....
regards,
Al
Alvaro Jaramillo
Senior Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/ Home of the California Fall Challenge!!
alvaro at sirius.com
Birds of Chile and New World Blackbirds at : http://www.sirius.com/~alvaro