Tweets,

We've been round and round on this crow thread over the years. I've lived in and near Seattle since 1972 and have yet to be convinced that there are two distinct populations of crows in western Washington, certainly not since Euroamerican settlement, land clearing, and the construction of highways that now provide easy passage to crows across the cascades and up and down the coast. There are no physical or ecological barriers that might separate two crows and there has never been an obvious contrast in morphology, vocalizations, or behavior between interior and coastal crow populations. Also, it has never been made clear where the division between Northwestern and American crows might have been on the outer coast, as there are crows all up and down the coast from Alaska to California and probably have been so for centuries, with no obvious ecological barrier between Grays Harbor and Cape Flattery. Do Oregon coastal crows avoid foraging on the beaches? Yet no one has suggested that they are Northwestern Crows. I would be surprised if crows anywhere were so rigid in their behavior as to pass up an inviting food supply, on the beach or otherwise.

The idea that there are two crow species here has not always been the preferred opinion, as Dawson in _The Birds of Washington_ (Dawson & Bowles, 1909) dismissed the notion that the Northwestern Crow was a good species analogous to the Fish Crows of the Atlantic Coast. He was subsequently overruled and in the current splitter-dominated climate the burden of proof is on those who would lump the crows, despite the lack of any convincing evidence that two species are involved.

Not that the issue hasn't been carefully studied. D. W. Johnston published an analysis of North American _Corvus_ populations (_The Biosystematics of American Crows_, UW Press, 1960) and concluded that the crow populations in western Washington varied clinally in all relevant measurements between "typical" Northwestern Crows on Vancouver Island to "typical" American Crows along the lower Columbia River. He compared a large number of museum specimens from documented breeding populations. Of course, that was before systematic studies of vocalizations and DNA.

For someone used to east coast crows ours will seem quite different, but one would note the same for our Song Sparrows, to mention just one example.

I missed the WOS presentation by the UW researchers a couple of years ago, but apparently they found limited genetic contrasts between Seattle crows and Vancouver Island crows, less than what one would expect if two species were involved.

Gene Hunn
Lake Forest Park, WA
enhunn323 at comcast.net



-----Original Message-----
From: tweeters-bounces at mailman2.u.washington.edu [mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of scompton1251 at charter.net
Sent: Wednesday, December 23, 2009 4:13 PM
To: Bob Norton; notcalm at comcast.net
Cc: Jon Leland; tweeters at u.washington.edu
Subject: Re: [Tweeters] NW vs AM Crow

Washington birders,

A most perplexing question, especially to someone from the southeast who has yet to see a "countable" Northwestern Crow. I have observed Crows closely in Seattle several times and have the distinct impression that they are smaller and more compact than the typical American and Fish Crows around here. They really seem different. I await with interest further investigation. Meanwhile, I'll head north of Seattle to see a safely countable NW Crow. Darwin would have loved this one.

Steve Compton
Greenville,SC
---- notcalm at comcast.net wrote:
> Bob and others,
>
>
> I found an unusually small crow on the beach at Hoquiam in mid -September, 2009. I have observed Crows and Ravens in a wide variety of settings for the past several decades, including adults and juveniles (AMCR- each year they successfully nest 50- 100 feet from our home and feed, learn to fly and bathe on our deck- first bath is truly a beautiful thing to watch) on our property for many years. This one was obviously and distinctly different: clearly smaller. It had the "correct " and expected proportions in relation to the AMCR. I concluded that it was the first obvious NW CR I had seen. Of course it may have been an unusually small ( -2 SD for size/ weight) American Crow.
> I will photograph the next one I see and send it to the group. I would encourage others to do so as well.
>
>
> Best,
> Dan Reiff, PhD
> Mercer Island
>
>
>
>
> ----- Original Message -----
> From: "Bob Norton" <norton36 at olypen.com>
> To: "Jon Leland" <jon_leland at yahoo.com>, tweeters at u.washington.edu
> Sent: Tuesday, December 22, 2009 9:00:27 PM GMT -08:00 US/Canada Pacific
> Subject: Re: [Tweeters] NW vs AM Crow
>
>
> The people who examine crows at the University of Washington say there are no Northwestern Crows in Washington. They have not been able to find any Crows in Washington with the correct measurements. North of the Frasier River in British Columbia they are all Northwesterns except for one area in Alaska where the American Crows get to the salt water.
> If anyone else knows otherwise, please expound and quote your sources.
> Bob Norton
> norton36 at olypen.com
> Joyce (near Port Angeles), WA
>
>
> ----- Original Message -----
> From: Jon Leland
> To: tweeters at u.washington.edu
> Sent: Monday, December 21, 2009 1:04 PM
> Subject: [Tweeters] NW vs AM Crow
>
>
>
> Hi all:
>
> For those you listers, I am curious how you handle ID and tracking for American vs Northwestern Crow. The resources I have consulted suggest that it is impossible to tell the difference other than range. Do you just count it as NW Crow when youre on the Pacific Coast and AM crow the rest of the time? I use eBird to track my sightings, and am a little amused that they even offer "American/NW Crow hybrid" as a common species.
>
> Regards
> Jon Leland
> Seattle WA
>
>
>
>
>
>
>
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