A Baird's Sandpiper lingers as Wrightsville's pool drops

A shorebird that usually crosses the continent a thousand miles west of here has been feeding at Wrightsville Reservoir in East Montpelier for more than a week.¹ Baird's Sandpiper (Calidris bairdii) showed up in six separate reports between August 21 and the end of the month, never more than two birds at a time.¹

It is one of the small brown sandpipers birders lump together as "peeps," and the way to pick it out is structural rather than a matter of color. Its wingtips extend noticeably past the tip of the tail, giving the bird a long, tapered, attenuated look that the other peeps don't have, and a brownish buff wash spreads across the chest where most peeps are gray and white.² On a flat it also gives itself away by where it stands: while the others probe at the waterline, Baird's works the drier margins above the water.

That habit is tied to the kind of trip it is on. Baird's Sandpiper breeds in the high Arctic and winters in South America, and instead of running down the coast it migrates through the continental interior, funneling in bulk through the Great Plains.³ Inland Vermont sits off to the side of that corridor, an uncommon stopover rather than part of the route.³ Birds that do stop here are refueling on invertebrates in exposed sediment, and reports spread over more than a week suggest birds staging to feed rather than one flyover seen twice.¹

Wrightsville is a flood-control detention basin rather than a water-supply reservoir, built to sit low through the dry season and fill only when runoff spikes. Inflow has fallen off sharply: the gauge on the North Branch of the Winooski at Wrightsville has dropped from about 62 cubic feet per second within the past month to 8 as of today, with gage height down roughly a foot and three quarters over the same stretch.⁴ Washington County went from no abnormally dry area at all in late July to 70 percent abnormally dry for the week of August 25 to 31.⁵ In a basin shaped like this one, falling pool stage would be expected to bring the shallow upstream margins up out of the water as bare sediment, the kind of surface a Baird's Sandpiper is built to walk — though confirming that link at this specific site would take a closer look at the reservoir's bathymetry rather than the gauge record alone.