Sanderling

If you happen to be on one of New Hampshire’s coastal beaches from August through May and see a flock of sandpipers running back-and-forth with the incoming waves, chances are you’re looking at Sanderlings. These are one of only a handful of shorebirds that spend the winter in the state, although their numbers vary from year to year. And it’s not just New England beaches that this species frequents. It occurs along the shorelines of all continents except Antarctica during the non-breeding season, and in the western hemisphere can be found from southern Canada to the southern tip of South America.

Like so many shorebirds, Sanderlings are on the decline. The factors involved are likely similar to those for other species, but a few aspects of Sanderling ecology might make them a little less vulnerable to some threats. For example, they are not common during late summer when beaches get a lot of use by people, which might reduce the risks inherent in frequent disturbance. At the same time, they occur primarily on beaches, so a greater proportion of birds are probably subject to disturbance at any given time. In late fall and winter they’re more likely to have the beaches to themselves.

During spring migration Sanderlings share a threat with the threatened Red Knot: changes to food supplies. Both species feed extensively on Horseshoe Crab eggs during this critical period when they’re rebuilding fat reserves for one more marathon flight north to their arctic breeding grounds. Unfortunately crab populations are significantly depleted due to past harvest for uses as varied as fertilizer, bait, and medical testing (their blood has interesting properties). There’s also some evidence that horseshoe crabs are spawning earlier in the spring as a result of climate change, while birds have not changed their timing to keep up.