Common sandpipers (Actitis hypoleucos) are small waders native to the Euro-Siberian region. They form a sister species with the North American spotted sandpiper, and have even been recorded hybridizing when strays of one species commingle with another.
Description and Distribution
These are generally bicolored birds with plain greyish-brown outer feathers and white feathers underneath, with some slight mixing around the neck and head. The outer feathers are more barred and the overall plumage duller during the non-breeding season, and the feathers of juveniles are also more barred. When foraging, they will characteristically thrust their head and bob their tails.
Common sandpipers breed throughout the Euro-Siberian region of the Palearctic realm, particularly in temperate and subtropical regions of Europe and Asia. They winter throughout the Old World southern hemisphere, ranging from the Afrotropics through to Indomalaya and Australasia. They are not currently considered a vulnerable species, but their population does appear to be decreasing, no doubt thanks to their reliance on wetlands, an increasingly threatened ecosystem throughout the world. In some states in Austrailia, it is considered a vulnerable species.
Behavior and Ecology
Common sandpipers are at some times gregarious and at others rather lonesome. Along certain migratory routes, they tend to flock together, such as when they make stops on South Pacific islands during their migration north. Generally though, they tend to breed and forage either alone or in small groups. They breed on the ground near freshwater.
They typically forage by sight for invertebrates including insects and crustaceans on the ground or in shallow water. Additionally, they seem quite comfortable foraging on marine rocks along the coasts, which are also replete with invertebrates.
Taxonomy and Evolution
Common sandpipers are part of the genus Actitus, though they were originally placed by Carl Linnaeus in the genus Tringa, which includes shanks and tattlers. The genus includes only 2 species: the common sandpiper and the slightly larger North American sister species, the spotted sandpiper.
Based on DNA and fossil evidence, these birds probably diverged from shanks and tattlers during the Late Oligocine (around 23-28MYA). The group also appears to have been more diverse at that time until the Turgai Sea dried up, though only 2 species survive today.