Northwestern vs American Crows

[Harrier]

I know that these species are normally divided by the Coast Mountains, but do we ever get American Crows in the Fraser Valley? I ask because there is a crow has been hanging around my neighbourhood in Sardis lately that has a noticeably different, higher-pitched call than all the other birds it’s associating with. It definitely sounds more American than Northwestern. Is the call alone enough to differentiate between the two species?

[Ben]

I would say they aren't distinguishable. Maybe it's just a young bird, or its hoarse or something...

Here's a link to Mel's blog, that links to an article saying they are the same species... daretobird.blogspot.com/2018/12/scientists-in-wa-have-proven-that.html

[Gord]

Ive been hearing that there's some research coming out about this dilemma from some. For the Fraser Valley, as we understand the species, the cut off between the two is the Hope area. Even at Hope Airport Im not convinced and while Ive been thinking Northwestern especially in the past I've actually gone to regarding them as Northwestern/American when I make a note on them. For sure anything north and east of Hope it is still acceptable to call them American. Or is it. It is interesting that in Washington directly to the south the acceptable range for American Crow extends way further west than we have up here. If one looked at the range maps of BC and Washington there would be a sharp line on the 0 Parallel between our Northwestern and their American. The Northwesterns are considered to be quite coastal there. Possibly some terrain plays a partial role here given there's a bit of an obstacle between the Upper Fraser Valley and Washingtone by way of the mountains but in the Fraser Valley urban sprawl and the simple lay of the land of the Fraser Delta might have helped the Northwesterns penetrate further east?

[oldfulica]

Mar 9, 2019 9:18:45 GMT -8 Harrier said:

I know that these species are normally divided by the Coast Mountains, but do we ever get American Crows in the Fraser Valley? I ask because there is a crow has been hanging around my neighbourhood in Sardis lately that has a noticeably different, higher-pitched call than all the other birds it’s associating with. It definitely sounds more American than Northwestern. Is the call alone enough to differentiate between the two species?

if we can get Dusky Thrushes and and other Asian rarities showing up here, I see no reason why the odd American crow and hybrids (to make it more interesting) aren't frequenting our area also. However I can't tell them apart.

[Gord]

Len no doubt Americans can and will move around no different from other species. Not easy to say for sure what bird we hear vocalizing is making 'real' sounds and isn't making some goofy sound that they're well-known to do. Myself I'd welcome some clarity on the matter!