The Buff-breasted Sandpiper is among a group of shorebird species that defy preconceptions by preferring comparatively dry upland areas over wetlands, mudflats, and other habitats typical of waders. During migration and overwintering periods, in particular, use of agricultural lands suggests they are compatible with human-dominated landscapes, though this may also expose them to significant risks from agricultural chemicals and other changes in farming practices. A medium-sized shorebird, the Buff-breasted Sandpiper breeds sporadically along Arctic coastlines from central Alaska to Devon Island, Canada. It migrates through Canada, the central United States, and central South America to overwinter in Argentina, Uruguay, and Brazil, where individuals frequent heavily-grazed grasslands and grasslands adjacent to wetlands. Northward migration proceeds through central South America, across the Gulf of Mexico, and northward along a narrow band in the eastern Great Plains before the birds reach the Arctic coast.
The Buff-breasted Sandpiper has an exploded lek mating-system that is unusual among shorebirds. Such leks are dispersed over a large area, with males defending relatively small territories that provide no resources for females and simply serve as display sites to attract females. After selecting a mate, the females then leave to nest and raise their chicks elsewhere. Unlike typical lekking systems, females do not show a strong preference for a few dominant males and will mate with solitary males that are not associated with leks.
Formerly abundant, this species decreased substantially in numbers owing to commercial hunting in the late 1800s and loss of habitat along its migratory route in both the Great Plains of North America and overwintering grounds in South America. The extreme tameness of the Buff-breasted Sandpiper and its tendency to return to a wounded flock member made this species especially vulnerable to hunting. During the later half of the 1900s, the species’ use of agricultural landscapes during migration and overwintering periods resulted in exposure to agricultural chemicals that proved to be especially toxic to birds and transformed the landscape through grazing and cultivation. Ongoing and projected changes in climate are especially severe in the coastal Arctic where the Buff-breasted Sandpiper breeds and present a significant threat to the species' future. Recent surveys on the migration corridor are documenting stopover sites, but it remains unclear whether the population is stable or continues to decline.