Mar
02
Crows of the Northwest
By
Northwestern Crow is said to be the most abundant bird in Vancouver, and hordes of these brachyrhynchos look-alikes join the gulls on the beaches and flats of English Bay.
This time of year, when they aren’t picking through the muck or gleaning lunch from the Safeway dumpsters, they’re canoodling in public, no doubt intent on holding on to first place in the abundance stakes.
And to think all this was going on just above the heads of the joggers and dog walkers!
Allopreening is common in American Crows, but BNA says that the courtship display of Northwestern Crow, “if it exists, is subtle.”
It exists. And it’s not all that subtle to judge by these two!
4 Comments
March 3rd, 2010 at 12:51 am
Ah, but can you definitely and completely rule out that these two were vagrant American Crows?
;-)
March 3rd, 2010 at 12:47 pm
A good and irrefutable point! I’ve been trying to puzzle out a difference between the two taxa, and so far all I’ve come up with is that to my ear these Northwestern birds seem to have a *higher-pitched* voice than Americans–which is wrong according to “the literature.” Very frustrating.
March 4th, 2010 at 1:24 am
I find this a bit confusing: every field guide states that one cannot safely distinguish between Northwestern an American Crow (and everyone I’ve heard who has been to the Northwest states the same), yet somehow someone must have found enough differences for regarding them as separate species and the arguments must have been so convincing that the AOU agreed.
March 5th, 2010 at 5:50 pm
It gets even better, Jochen: Pyle says that “some to many” are not safely separated from *hesperis* American Crows “by in-hand criteria alone.” So indistinguishable in the field, indistinguishable in hand; all sounds a bit fishy (and indeed, some have, oddly, considered Northwestern and Fish Crows to be conspecific).