Last week the southbound migration of shorebirds started with a few sightings of spotted sandpipers, glossy ibis, black-bellied plovers and lesser yellowlegs. The latter two species are coming from the Arctic, where the season is so short that birds leave if their nesting attempt fails; the season is not long enough for them to re-nest and raise their chicks. July is pretty much a month where we will see adult shorebirds that are mostly in their breeding plumages. In August the youngsters will arrive in their finery while the adults molt into their much more drab winter plumages.

So, the migratory influx continues.

Gus Ben David saw his first of season spotted sandpiper at one of the ponds in his yard on July 3. Pete Gilmore and Lanny McDowell visited Eel Pond on July 5 and found another spotted sandpiper and two immature ring-billed gulls. On July 7 Shea Fee found four black-bellied plovers, nine short-billed dowitchers, two laughing gull and four ring-billed gulls on Norton Point. Adam Cowie-Haskell counted seven least sandpipers on Lobsterville Beach that day.

Philip Edmundson spotted two short-billed dowitchers, one lesser yellowlegs and five lesser black-backed gulls along West Tisbury’s south shore on July 8. He observed a spotted sandpiper along the shore of Watcha Pond on July 10. Also that day, Steve Allen found three greater yellowlegs at Felix Neck and Anne Culbert and I found five semipalmated plovers, six sanderlings, three least sandpipers and 18 short-billed dowitchers.

On July 11 Bob Shriber counted 10 least sandpiper, 11 short-billed dowitcher, two lesser yellowlegs and a killdeer in Aquinnah’s West Basin, and Warren Woessner one semipalmated plover and 14 short-billed dowitchers at Norton Point.

Terns are also on the move; those whose nesting attempts failed are now gathering into large roosting flocks at Norton Point. On July 7 Shea Fee also spotted 70 least, 150 roseate and 800 common terns. Two days later Makenzie Luce spotted 200 least terns, 100 roseate and 200 common terns roosting at the western end of Norton Point.

The numbers of these birds in this flock changes constantly as the terns arrive from or depart to their feeding grounds southward over the Ocean or northward to Edgartown Harbor and Nantucket Sound. This large flock is also a good place to look for the less common terns, though the first of these,…