Birds of the same species are quite capable of exhibiting just as much vocal
variation between local populations, e.g., White-crowned Sparrows.
Townsend's and Black-throated Gray Warblers are said to converge [or
diverge?] vocally where they occur in close proximity. Plus the difficulty
of comparing apples and oranges when a species is polyvocalic (that is,
makes lots of different sounds for different circumtances), not to mention
differences between juveniles and adults.

Gene Hunn.



At 08:05 AM 9/16/98 -0600, you wrote:
>Hi Gene and Tweets,
>
>Have you (or any Tweet) looked at sonograms of NW and American Crows? I
>have convinced myself in the past that I can hear a difference
>(particularly in the Vancouver BC area), but I seem to be in the minority.
>Anyway, I would assume that mild differences in regional 'accents' would not
>be sufficient by itself to justify classification as separate species. With
>the Red Crossbills, don't the various subspecies have different dietary and
>habitat preferences as well as separate calls?
>
>Rick Romea
>Seattle, WA
>rromea at stioptronics.com
>
>206-523-5831 (Home)
>425-827-0460 X 316 (Work)
>___________________________________
>
>If you feel like everything is under control,
>you're probably not going fast enough.
> - Mario Andretti
>
>
>
>
>