Date: 11/19/24 5:13 am From: Shaibal Mitra <Shaibal.Mitra...> Subject: [nysbirds-l] Individual Identities of Suffolk County Sage Thrashers
Examination of photos shows that the Sage Thrasher found by Aidan Perkins at Smith Point County Park on 22 October 2024 was a hatching-year bird that had replaced the innermost tertial on the left wing and the two inner tertials on the right wing. The retained juvenal feathers are smaller, more pointed, more worn, with browner centers and narrower pale edgings than the corresponding replaced formative feathers, which are larger, more round-tipped, fresher, with grayer centers and broader pale edgings:
Unsurprisingly, the Sage Thrasher found at Robert Moses SP Field 5 on 8 November was a different individual hatching-year bird, retaining all juvenal tertials on both wings:
(Despite the profusion of technically superior images of this bird in the Macaulay Library, this soft-focused image remains the most informative one available on this important point.)
The Sage Thrasher found by Russ Comeau at RMSP Field 5 on 17 November is the same individual as the previous one, evidently continuing undetected 9-16 November. This is not surprising, but it is also not a given, because vagrants often occur in clusters, and contexts such as these can plausibly host multiple occurrences of even very rare species. Like the earlier bird, it shows all juvenal tertials; more tellingly, it shows a break in the lower wingbar on the right wing, resulting from a smaller/weaker white tip to the third visible greater covert on that wing:
