Bird of the Month: Least Sandpiper

By Andy McCormick

Scientific Name: Calidris minutilla

Length 6 in

Wingspan 13 in

Weight 0.7 oz (20 g)

AOU Band code LESA

In the interior of North America the Least Sandpiper is the most common of the “peeps,” the small sandpipers in the genus Calidris. However, on the coast Least Sandpipers often associate with Western and Semipalmated Sandpipers and can be lost in their great numbers. Least Sandpipers generally travel in smaller flocks. The Least is smaller than either the Western or Semipalmated Sandpipers and in fact, it is the smallest of all North American sandpipers.

There are four characteristics that help birders distinguish the Least Sandpiper from the others: It is browner on the back than the other peeps; it has a brown breast, but white underparts overall; it has a short, dark, slightly drooping bill; and it has yellow legs. Comparatively, the bill of the Least is thin and droops a bit. The bill of the Western is heavier, longer and more clearly droops at the tip. The bill of the Semipalmated is heavy, straight and blunt. The brown breast of the Least Sandpiper is a good field mark for identifying these birds in flight. The Western and Semipalmated Sandpipers are larger and whiter looking.
The genus name Calidris is from the Greek kalidris, used by Aristotle for a speckled shorebird. The species name minutilla is from the Latin minitulus, very small or tiny (Holloway). The common name is from its small size. It is the smallest sandpiper in North America.

The Least Sandpiper does not breed in Washington, but passes through the state during both spring and fall migrations. Early spring migrants may be seen in late March with the peak migration in mid-May. Nesting sites vary from mossy, grassy sites to moist sedge and tussocks to flat, sandy islands, but virtually all breeding sites are in the wet, subarctic and northern boreal forest. The female chooses from a series of scrapes made by the male (Nebel and Cooper). The shallow depression suffices as a nest where four pale-buffy eggs are deposited. Downy young leave the nest soon after hatching and are attended for a short time by both parents (Kaufman).

The female is often the first to leave on the southward fall migration and the male follows when the young can fly in about two weeks after hatching (Nebel and Cooper). However, the young birds must forage for themselves and prepare for migration after both parents have departed. Migration occurs along all four North American flyways. Pacific coast adult Least Sandpipers can arrive in Washington in late June with juveniles peaking in August and September. They winter from the southern United States through Central and South America to Peru.

There are no species-specific conservation strategies in play for the Least Sandpiper, but general support for wetland habitat includes them as a target species. The Western Hemespheric Shorebird Reserve Network was established in 1986 and works to preserve shorebird habitat in North, Central and South America. The North American fall migrating population may number over 574,000, but census taking is very difficult because of the difficulty separating these birds from congeners Western and Semipalmated Sandpipers. The greatest threat to all of these sandpipers is loss of wetland habitat due to human development and the potential for even greater loss due to sea level rise resulting from global warming.