Re: Pleasant Hill White throated sparrow question


Stephen T Bird
 

Wintering white-throated sparrows have a relatively small range. This thesis tracked individual birds with radiotelemetry and found their home-range to be a few acres (see pages 2-6), Piper & Wiley by my interpretation got a similar result. 3/4 mi, by the paper's measurements seems it might be a little far. Anyone who chased that Harris (or White-throated just a bit more north of it) that was at Pacific Commons this winter (I think I've heard its still there) would agree that some species don't seem to move much. The range of Bachmann's was a bit bigger, but the more distant Nelsons & Saltmarsh was much greater. It seems that unwillingness to spread out, for white-throated, can be true foraging at even very short ranges making a trade-off when protection is near. That said, photos and careful details might prove otherwise! Birds do whatever their hearts desire sometimes.
-Stephen

On Fri, Feb 26, 2021 at 10:35 AM Alan Bade <alanb1491187@...> wrote:
After taking our feeder down due to sick Pine Siskins, our White throated sparrow has been much less frequent. (It's been a regular for 2 winters.) I've been putting seeds out for it on rocks in the yard in a socially distanced manner. Today, it was back after not seeing it for about 2 weeks; https://ebird.org/checklist/S82371848

We looked for white throated sparrow yesterday on our Oak Park Grayson Creek bird survey, as there have been two sightings in the area (approx at the intersection of Astrid Lane and the EBMUD trail https://goo.gl/maps/pBvMcE8bR1BKJNp9A). One was in December and one in mid-Fed. (R. Raffel and D. Heins). This is near where the Chipping sparrows hang out.

While we had a good day for sparrows on the survey (Lincolns, Savannah, Golden-crowned, White-crowned, and Song sparrows), we didn't see the White-throated. https://ebird.org/checklist/S82336241 We didn't go further north to look for the Chippies, but I saw them recently, so they're still there.

Which leads me to a question for more advanced birders than I; how far do sparrows like White-throated go in their foraging rounds? Could the tan-striped individual we see at home also be the one 3/4 mile away? Ours is always in a small flock of white-crowned sparrows. I've been checking regularly over at the Astrid site and always see a large mixed flock of white-crowned and golden-crowned. There is excellent cover over there.

Perhaps this is the same bird? Thanks in advance.

Alan Bade
Pleasant Hill



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