Lyn,

Most if not all Washington birders long ago gave up trying to sort out
Northwestern versus American Crows. I believe they are one species that
intergrades throughout western Washington, with perhaps the most
Northwestern-like crows on the north and west shores of the Olympic
Peninsula, as well as in coastal British Columbia. Observers have tended to
assume that crows north of Bellingham were "Northwestern," but I believe
that is quite an arbitrary judgment, as there is no clear line between these
two types as one moves south and/or southeast, at least not since
Euroamerican settlement and the extensive clearing of west side forests.

As for the low pitched calls, these could well be young birds of the year or
just a contrast that you noted in comparison to crows back east. Such
contrasts are certainly not definitive evidence of a species distinction. A
rather comprehensive analysis of crow taxonomics was published in 1960 that
indicated that crow measurements increased incrementally as one moved south
from Victoria to Portland, with no clear break. Also, genetic and laboratory
analyses at the University of Washington, as I understand it, indicate that
the genetic distance between Vancouver Island crows and Seattle crows is
less than what one would expect if they were in fact good species.

Gene Hunn
Now in Sonoma, California
enhunn323 at comcast.net

-----Original Message-----
From: tweeters-bounces at mailman1.u.washington.edu
[mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Lyn Topinka
Sent: Monday, June 20, 2011 11:38 AM
To: tweeters at u.washington.edu
Subject: [Tweeters] RFI - Northewestern Crow ...


hi all ... do we have Northwestern Crow here in the Vancouver,
Washington and Portland, Oregon area ??? ...

I know nothing about Crows but have been hearing a lower-pitched
"caw" in the mornings, about half-way between American Crow and
Common Raven ... so I listened to the calls of the 3 species on
AllAboutBirds website and what I am hearing is closest in pitch to
the Northwestern Crow ... my location is urban Vancouver ... we do
have Crows nesting in the area ... I've always heard a higher-pitched
"caw" until just recently when this lower pitched has shown up, along
with the higher pitched "caws" ... I know it is not the Raven ...
just wondering if the Northwestern is seen this far south ...

Lyn




Lyn Topinka
http://EnglishRiverWebsite.com
http://ColumbiaRiverImages.com
http://RidgefieldBirds.com

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