Saturday, July 14, 2012

The Summer Sandpiper

Spotted sandpipers are the most widely distributed shorebird in North America, breeding throughout Alaska, Canada and most of the Lower 48 States (except for the Deep South).  Arriving on breeding grounds before the males, the larger and more aggressive females establish territories on which they often mate with a number of males; in fact these queens of the bird world leave incubation and child rearing duties to their male partners and, since she is capable of storing sperm, these hapless males may end up caring for a brood fathered by one of her other suitors.  Nest sites, also chosen by the female, are shallow, grass-lined depressions hidden by vegetation and placed near a freshwater stream, pond or lake.

Throughout the warmer months, spotted sandpipers are usually found alone, bobbing along the edge of a stream bank or shoreline.  When disturbed, they fly off on fluttering, stiffly held wings, dropping back to the ground within a short distance.  They are active feeders, snaring insects, other invertebrates and small fish from the vegetation, mudflats or shallows.  Best found along rocky streams, spotted sandpipers are easily identified by the above behavioral traits and by their spotted breast and abdomen; the distinctive spots are lost when they molt to their winter plumage.

Here in Colorado, spotted sandpipers are common along the South Platte and Arkansas Rivers and their  Piedmont tributaries but are also found along mountain streams and in the drier canyon country of the Western Slope; these adaptable birds are also among those species that inhabit wetland areas of the alpine tundra.  Come fall, spotted sandpipers head for southern coasts of the U.S., Mexico and Central America where they retain their preference for freshwater habitats.