Vincent,

Absolutely due to warmer winters. I'm writing this from Port Townsend,
where Calif Scrub-Jays are now resident.

The trend in California Scrub-Jay mirrors similar increases with a long
list of non-migratory or less-migratory species from Calif/Oregon that are
expanding north into the Pacific Northwest, as well as east into eastern
Washington and Idaho (e.g. Black Phoebe, Red-sh Hawk, Anna's Hummingbird,
Great Egret, Lesser Goldfinch, Turkey Vulture). While expansion for some
species began over 50 years ago, it really took off around the mid-1980s,
matching a "regime change" that has been detected across many species and
ecosystems worldwide. This regime change now keeps happening faster and
faster.

It will be interesting to see how jays deal with the mountains and forests
north of Vancouver, WA-- that may prove an obstacle to further expansion,
though I expect them in Kamloops in a few years. Note that not all resident
species are flexible-- Oak Titmouse and Nuttall's Woodpeckers are dependent
on oaks, whose "migration velocity" is far slower than "climate velocity"
(i.e. oaks can't fly, and they cannot move north as fast as the weather
is). Jays can rely on a variety of foods, including (especially) around
human habitations. Note that jays are big time nest predators, so all those
peanuts at bird feeders potentially subsidize predation of local open cup
nesters (e.g. robins, vireos, warblers, grosbeaks, flycatchers, etc.).

Here is a blog post using CBC data with graphs for some of the bird species
expanding north:
The invasion of the Pacific Northwest: California's birds expand north with
warmer winters
https://thecottonwoodpost.net/2020/03/09/the-invasion-of-the-pacific-northwest-californias-birds-expand-north-with-warmer-winters/



On Mon, Sep 20, 2021 at 1:51 PM Vincent Lucas <vincentlucas5 at gmail.com>
wrote:


> There was A California Scrub-Jay (poor photo) in my old neighborhood here

> in Port Angeles. Clallam County a week or two ago. They do seem to be more

> frequent in areas not normally where they are encountered. Perhaps global

> warming or wildfires are the cause? Mere speculation on my part.

>

> Vincent Lucas

> Port Angeles

> --

> Sent from Gmail Mobile ʚϊɞ ʚϊɞ ʚϊɞ

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--
Steve Hampton
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