Allan Strong wrote: "Let me through out a couple questions...maybe you
can answer them Walter. To me, the facial pattern seems wrong for a
Semipalmated, which seem to show a stronger supercilium pattern. Is
this a useful ID point?"
Many Semi Sandpipers do show a pretty clear whitish supercilary, but, as
photos in both Paulson and O'Brien et. al. show, some individuals do
not. Given this bird is in very bright and fresh plumage the buffy
overtones on the head obscure the fairly broad pale supercilium on "bird
one". Note the contrast with the dark lores and auriculars.
Allan Strong wrote:
"Additionally, not being a real expert on Baird's, I would think that
the primary projection on bird #1 despite perhaps not being as long as a
"typical" Baird's, is still longer than what you would see on a
Semipalmated, especially if you compare extension beyond the tail as
opposed to beyond the tertials."
As Pat aptly pointed out the angle is misleading, which is why I counted
primary tips. To be really sure of the shape difference the bird would
need to be shown in profile, not 3/4 turned.
Allan Strong wrote:
"Since the 'scaley' back pattern of Baird's seems to be an easy way to
pick juvenile birds out of large flocks, I find that I probably don't
pay as close attention to molt patterns in adult Baird's. Would adults
still be in alternate (worn, presumably, obviously not the case here)
plumage in VT in September or do they molt prior to departure?"
Adult Baird's Sandpipers are extremely rare in eastern North America
because they migrate down the Rockies and adjacent western Great Plains
and onward through the mountains of Central and South America. Adult
Baird's have occurred a few times in fall migration in New England over
the last decade, but all have been reported in late July and early
August. By this date (post-Labor Day) only juveniles should be present,
an adult would be extraordinary. Adult Baird's Sandpipers have a body
molt before migration and complete the molt on the wintering grounds in
South America with the coverts and flight feathers.
I want to repeat that the Semipalmated Sandpiper pictured is about as
brightly colored as one is likely to be. Pat is quite right that the
bird is long-billed as well, almost certainly a female. One of the
trickiest things to learn in bird ID is that you are not identifying a
species you are identifying an individual from that species. And let's
not even talk about hybrids. Birding would be so easy if birds were clonal.