Friday, May 24, 2013

Fri-D Peep Bonus: Western Sandpiper

[Western Sandpiper, Stone Harbor Point, NJ, April 14 of last year. This bird almost certainly overwintered at or near Stone Harbor, and should be considered a lingerer more than a migrant.]

On Western Sandpiper (WESA), quoting David Sibley's Birds of Cape May (1997), "Despite published reports, there are no documented records of spring migrants." We maybe know a little bit more about Western Sandpiper status than we did 16 years ago, but we can pull a similar trick with this id. to what we do with dowitchers: "In May, in NJ, they're all Semipalmated Sandpipers (SESA)." Or almost all.

By the way, what we say about NJ and spring shorebird status generally applies to all the northeastern states.

Westerns do occasionally overwinter in NJ (SESA's do not), and if one sticks around long enough in spring you can see it in breeding plumage. Compared to SESA, WESA has more rufous above, distributed in a localized way on the scapulars, ear coverts and eyebrow/crown. Below, WESA's "streaking" is more spotting, with at least some of those spots taking the form of  chevrons, and with many distributed down the belly and flanks, farther than on SESA.

If you've looked at a lot of peep, you can use WESA's front-heavy structure, in particular the thick neck and large head, and the longer, drooped bill to tell it from SESA.

Western, like Long-billed Dowitcher, is another species I've never seen in NJ in May, but I believe they do occur, and when they do, I believe they are birds that wintered locally or nearby, and I am sure they need to be documented thoroughly with good field notes and/or photos.

I don't want to discourage people from looking for spring WESA's (or LBDO's or anything else), just know that a measure of caution is advised.

[Here's a typical May Semipalmated Sandpiper for comparison, May 26 of last year in Great Sound, Cape May County, NJ. Note the less extensive rufous, less extensive spotting below, lack of chevrons, shorter bill, smaller head, thinner neck. . .you should string about half a dozen field marks together and consider relative status for the season and location before you identify members of this species pair. There's a range of variation on these things, so study a bunch of them to learn just how bright a SESA can be above, how much streaking they can have below, how long their bills can be. . .]

1 comment:

  1. Thanks for the compliment, and for commenting! Let me know what other i.d. or other topics you'd like to see on the blog.