Semipalmated Sandpiper

The small confusing sandpipers collectively known as “peeps” are only found in New Hampshire during spring and fall migration. Of these, the Semipalmated and Least Sandpipers are the most likely to be encountered. Separating these two species often requires looking at several features. Leg color is the most reliable, with Leasts having greenish-yellow legs compared to the Semipalmated’s black ones (beware of birds with muddy legs). Leasts are also browner, have a finer bill, and are clearly smaller than Semipalmateds in direct comparison. If birds are far or way or in a dense flock, it might not be possible to identify them to species.

Although similar in appearance, these two shorebirds differ in several aspects of their ecologies. Although both are found across the arctic, Semipalmateds breed farther north and are restricted to the tundra and winter entirely along tropical coastlines south of the United States. In New Hampshire they are far less likely to occur inland than Leasts but are one of the most abundant shorebird species along the coast in the fall, when counts of 2000 have been reported. The numbers we see here, however, are but a fraction of the population that migrates south through the Northeast in fall. The Bay of Fundy is a critical stopover site for birds migrating to the Caribbean and South America. Flocks of hundreds of thousands have been reported here, and it’s estimated that over half the global population passes through this area between July and September.

Unfortunately, the numbers of Semipalmated Sandpipers using the Bay of Fundy have plummeted by 50% since the 1980s. As is the case with other declining shorebirds, potential or known threats include hunting in the Caribbean, climate change, loss of coastal habitats to development, and increased human disturbance during migration. Keep the latter in mind the next time you encounter a flock of sandpipers on a New Hampshire beach. If you cause them to flush they waste valuable energy that they need to make an overwater flight to South America, and if they waste too much they might not be able to make the trip.