[Tweeters] CBC trends in a warming world
dennispaulson at comcast.net
Thu Nov 17 12:04:32 PST 2022
Thanks for the interesting information, Steve. Just to show why large datasets are important, this is the first winter in years when we HAVEN’T had Yellow-rumped Warblers in our yard in Seattle. We have had up to 8 birds one year, 6 another, and usually no more than 2-4, often both subspecies. We also have 1-2 Townsend’s Warblers every winter but only a few sightings of Orange-crowned in winter. I think they remain for the winter only because of our feeders with suet and bark butter.
We saw a Hermit Thrush one day in one winter but never Cedar Waxwing or Lincoln’s or White-crowned Sparrow in winter. Our wooded yard is probably inappropriate habitat for some of these species in winter, although we have seen them all in migration.
> On Nov 16, 2022, at 12:10 PM, Steve Hampton <stevechampton at gmail.com> wrote:
> With the Christmas Bird Counts coming up, I want to share some recent analysis I did for six species that are at the northern edge of their wintering range in the PNW. Research suggests many species (especially non-migratory species and short-distance migrants) are shifting their ranges north, both in summer and winter. CBCs, with their long history, are great at tracking large scale distribution changes over time, something that eBird just can't do yet. A lot of publications are now using CBC data to track climate change issues.
> I looked at Cedar Waxwing, Hermit Thrush, White-crowned Sparrow, Lincoln's Sparrow, Orange-crowned Warbler, and Yellow-rumped Warbler. I found all were increasing, to some degree or another, on CBCs in the PNW.
> The details and graphs are here:
> Heading south for winter, more birds are choosing the Pacific Northwest <https://thecottonwoodpost.net/2022/10/07/heading-south-for-winter-more-birds-are-choosing-the-pacific-northwest/>
> Previously, I've posted about the expansion of California Scrub-Jays <https://thecottonwoodpost.net/2021/10/28/mapping-the-expansion-of-the-california-scrub-jay-into-the-pacific-northwest/> and Lesser Goldfinches <https://thecottonwoodpost.net/2021/03/15/the-song-of-the-lesser-goldfinch-another-harbinger-of-a-warming-climate/>, as well as a number of non-migratory species (Anna's Hummingbird, Black Phoebe, others) 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/>
> Our CBC data is being used!
> good birding,
> Steve Hampton
> Port Townsend, WA (qatáy)
> Tweeters mailing list
> Tweeters at u.washington.edu
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