Date: 9/20/26 5:42 am From: Katz, Nurit via groups.io <nkatz...> Subject: Re: [LACoBirds] Clark's Nutcrackers at Upper Shake Campground
Thank you Kimball. Do the pines they feed on have mast years? Could that be the cause of the irruptions?
Thank you,
Nurit
Encino, CA
From: <LACoBirds...> <LACoBirds...> On Behalf Of Kimball Garrett via groups.io
Sent: Saturday, September 19, 2026 8:19 AM
To: <edstonick...>
Cc: <naresh.satyan...>; <LACoBirds...>
Subject: Re: [LACoBirds] Clark's Nutcrackers at Upper Shake Campground
Ed,
The main thing that this fall's irruptive species have in common is a diet that depends largely on pine seeds. So I wouldn't expect ecologically very different species (such as a boreal forest waxwing) to be involved, except through coincidence. Likewise, there is little indication (at least up to this point) of any strong irruptions of finches into our region (a few siskin and crossbill reports, but no local Evening Grosbeak reports, for example).
Besides the corvids, there are lots of Red-breasted Nuthatches in the lowlands, and Mountain Chickadees seem much more widespread on the deserts than in most falls. I wonder about the possible presence of Great Basin/Rocky Mtn. Mountain Chickadees this fall (subtly different, with buffier flanks and a bit more white on the supercilium and forehead), and apparently there has been at least one "Interior/Mountain" White-breasted Nuthatch (tenuissima, with the distinctive staccato call notes) in the coast range north of L. A. County. Birders should be aware of the potential for that taxon in L. A. this fall (though the 2-3 White-breasted Nuthatches I have found on the Antelope Valley floor this fall have been coastal aculeata). Please try to record vocalizations of any desert lowland (or odd-sounding coastal) W-b Nuthatches.
We still don't know where these corvids are coming from, other than conifer forests and woodlands somewhere from the Sierra Nevada east to the Rocky Mtns, (thus, likely much of the Great Basin as Naresh indicated). And unless the Santa Barbara folks have figured it out, we don't know where the triple (even quadruple) digits of Clark's Nutcrackers seen almost daily at La Cumbre Peak are coming from and headed to each day and whether it is new birds or repeat birds each day.
The good news is that there are lots of birders out there reporting on eBird, and maybe by the end of this season's phenomenon we'll have a better understanding of the patterns that are unfolding.
This is the first I've heard of an invasion of northern Great Basin birds to L. A .County.
Have there been similar events in the past? What else might we expect in Southern or other parts of California e. g. Bohemian Waxwings, woodpeckers, etc.
I had a couple of Clark's Nutcrackers at Upper Shake campground (west of Lake Hughes) this evening. There are no previous reports of this species in the western part of the Angeles National Forest (west of about Mt Gleason), at least on eBird. It is hard to be sure what's going on with nutcrackers in the eastern San Gabriels where there is a resident population, but these birds would appear to be solidly linked to the ongoing corvid irruption from the Great Basin.
I did not hear any Pinyon Jays (or see any, but my chances of seeing a silent bird were pretty slim).
