Spotted Sandpiper

About the Spotted Sandpiper

In breeding plumage, the Spotted Sandpiper is easy to identify by the bold dark spots covering its white underparts, paired with brownish upperparts and a habit found in almost no other shorebird: a constant teetering, bobbing motion of the rear body and tail as it walks. In flight it shows shallow, stiff, fluttering wingbeats low over the water, quite different from the smooth flight of most sandpipers. Nonbreeding and juvenile birds lack the spots below, appearing plain white, but usually still show the telltale bobbing gait, which remains one of the most reliable ways to identify the species at any season and at almost any distance.

The species breeds across nearly all of North America wherever there is fresh water with some open shoreline, including ponds, rivers, and lakes throughout Oklahoma, and it winters from the southern United States south through Central America and much of South America. Because it tolerates a wide range of freshwater habitats, it is one of the most widely distributed breeding sandpipers on the continent, equally at home along a quiet farm pond, a rocky mountain stream, or a slow, muddy river.

It forages by walking along shorelines, picking and probing for insects and other small invertebrates, and will also dart out to snatch flying insects near the water's edge. Its plain, active foraging style combined with the bobbing walk makes it recognizable even at a distance or in poor light. Unlike many shorebirds that gather in dense flocks, Spotted Sandpipers are typically encountered singly or in loosely spaced pairs along a shoreline, each individual patrolling and defending its own stretch of bank rather than tolerating close neighbors.

Spotted Sandpiper breeding biology is unusual: females frequently practice polyandry, mating with more than one male in a season, while each male takes on most of the incubation duties and chick care for his own clutch, a reversal of the roles typical in most birds. Females also tend to be the more aggressive sex when it comes to defending territory and competing for mates, arriving on the breeding grounds first in spring to establish and defend a territory that may attract more than one male over the course of the season. Chicks are precocial and can swim short distances almost immediately after hatching, an ability shared by adults if pressed, which is unusual among sandpipers generally.

This flexible mating system allows some females to produce several clutches with different males across a single breeding season, boosting their overall reproductive output well beyond what a single pairing could achieve in the same span of time. Because each male is left to incubate and raise his own brood largely on his own once a clutch is laid, individual males can end up caring for chicks that hatch at different times if a female moves on to a new mate nearby, adding a layer of overlapping parental duties rarely seen among North American shorebirds. The species' tolerance of a huge range of freshwater habitats, combined with this unusual breeding system, has made it a valuable subject for research into the evolution of sex-role reversal in birds more broadly.

Spotted Sandpipers place their nest, a shallow scrape lined with grass and other plant material, on the ground near water but usually a short distance back from the immediate shoreline, tucked among grass or low vegetation for some concealment. Elevated hormone levels associated with this role reversal have been documented in females of the species, part of the physiological basis researchers point to when explaining why females here take on the more typically male behaviors of territory defense and mate competition. Migrants returning each spring tend to reclaim the same stretch of shoreline used in previous years, and the sight of one bobbing along a dock, riverbank, or lakeshore anywhere in Oklahoma during the warmer months is often the easiest way for a beginning birder to learn this species' unmistakable gait.