new White-throated Sparrow, Cassin's Vireo, seasonal (record) totals for scarce winter passerines 2020-2021
On Thursday the 18th, the wintering Ash-throated Flycatcher continued at dawn (6:30AM)--the only reliable time--in Rose Teeple Park in Imperial Beach, and, as almost always, it likes the Carrotwood trees along the west edge. There is yet another, new White-throated Sparrow in town, this one along Leon Avenue in Nestor, and it is likely a returning bird from last winter that had been missed earlier this season. As is typically the case with this species, it likes to hang out with White-crowned Sparrows (a group of 8+), today at # 2165 Leon, whereas a year ago it was just to the west at #2105. And the individual Cassin's Vireo at the top end of Nestor Park, first seen this season by B. Carlson on the 15th, continued today. It is almost certainly the same bird wintering at this site for at least the past four winters, but totally missed this entire winter until now.
My database county totals for the following scarce-but-regular winter species are mostly above average, some new all-time record seasonal totals. But be aware that for a fair number of these species, many of the individuals seen in December are never seen again; so whether they didn't survive, shifted slightly, were simply not looked for again, or were, in fact, very late fall migrants rather than true locally wintering birds is uncertain. So.... totals from 1 December 2020 thru 17 February 2021:
White-throated Sparrow: 15 (new record)
Green-tailed Towhee: 28 (double the previous record!)
Bullock's Oriole: 38 (approx. third highest total; a bit surprising given this species, and its favored trees, seem to be declining)
Nashville Warbler: 23 (new record by 2)
Yellow Warbler: 31 (average)
Black-throated Gray Warbler: 40 (new record by 5)
Wilson's Warbler: 39 (new record by 10)
Western Tanager: 50 (near average; all-time record is 66)
In contrast, Black-and-white Warblers are slightly below average, and Summer Tanagers are well below recent winter totals.
--Paul Lehman, San Diego