A monograph by David W. Johnston called "The Biosystematics of American
Crows" (U. W. Press, Seattle, 1961) argues the case for lumping the
Northwestern Crow with the American Crow. He measured all known specimens of
W. Washington crows collected during the nesting season and concluded that
they exhibit a clinal pattern, progressively increasing in wing, tarsus,
culmen, & tail length as one moved north from the Columbia River to British
Columbia. He did not do a definitive analysis of vocalizations, however. The
"poohbahs" of the AOU, for some reason, have seen fit to discount this
evidence, leaving the two as separate species. Us local "poohbahs" have
never been able to see any good evidence to suggest that there were two
distinct populations of crows in Western Washington. Traditionally, the
"Northwestern Crow" is said to occur along the outer Olympic Peninsula coast
and (perhaps) throughout Puget Sound). However, since there are now crows
everywhere in between, there's no obvious ecological / habitat boundary that
would separate them. I have on occasion had the opportunity to measure road
kills from Seattle and they fell precisely between the two ranges. I believe
the species were originally split (back at the turn of the century, but it
was controversial then) on the basis of the analogy with the Atlantic Fish
Crow. However, Fish Crows are not difficult to distinguish and probably had
many more millenia to evolve as a separate species than the Pacific coastal
populations, which must date to just the last phase of the last Ice Age
(10000 years ago) when a narrow ice-free coastal strip was isolated by the
Puget Lobe of the Cordilleran Ice sheet from other American Crow populations.

Gene Hunn.



At 07:42 AM 9/15/98 -0700, you wrote:
>
>Tweeters,
>
>This e-mail raises a question about Northwestern Crow: Is Northwestern Crow
>a separate species or a subspecies of American Crow? National Geographic
>states that many experts consider it to be a subspecies of American Crow.
>Does anyone know of research that can answer that question? My
>understanding is the grand poohbaws of Washington consider it a subspecies.
>Of course, at birdathon time it is considered a separate species for its
>monetary value.
>
>If it is a separate species, how far north do we need to go to be fairly
>confident that the smallish crow we are looking at is a Northwestern? Where
>to American Crows fade out and give way to nearly-pure Northwesterns?
>
>Denny Granstrand
>Yakima, WA
>
>
>>>Hello,
>>>
>>>I spent last weekend on the west side of the Olympic peninsula at Tahola
>>>Beach on the Quinault Indian Reservation. I saw many crows in the coastal
>>>forest along the beach. Is it safe to assume that these were Northwestern
>>>Crows or is there a range overlap in or near this area?
>>>Thanks,
>>>
>>>Gerrit Vyn
>>>GVYN at vanstar.com
>>>
>>>
>>>
>>>
>>>
>>>
>>
>
>osprey at nwinfo dot net
>
>
>
>