[order] Charadriiformes | [family] Scolopacidae | [latin] Tryngites subruficollis | [UK] Buff-Breasted Sandpiper | [FR] Bécasseau roussâtre | [DE] Grasläufer | [ES] Correlimos Canelo | [IT] Piro-piro fulvo | [NL] Blonde Ruiter

Blonde Ruiter determination

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This upland shorebird has an unstreaked buff-colored breast, yellow legs, and a brown and buff mottled back. It has a dark tail and rump, streaked like the rest of the back. Its short, narrow bill and round head give it a plover-like appearance. Its underwings are silvery-white. Breeding and non-breeding adults look quite similar. Juveniles are darker and grayer, and have a scaly pattern on their backs.
Buff-breasted Sandpipers roost in large flocks, although their numbers in Washington are not large enough for single-species flocks. While foraging, they walk steadily along with a high-stepping gait, bobbing their elevated heads looking for prey on the ground. They may run and stop, making quick directional changes like plovers do.

Buff-breasted Sandpipers breed in dry Arctic tundra. Outside of the breeding season, they are seen in short-grass prairie and other grassland habitats. They winter in the grasslands of southern South America. In migration, they can be found on grassy areas such as golf courses, cemeteries, mowed lawns, and airfields. They are often seen in the baked mud around drying rivers, lakes, and reservoirs. They can also be seen along sandy beaches and open, weedy meadows.

Tryngites subruficollis breeds sporadically along arctic coasts from central Alaska, USA to Devon Island, Canada, with a relict population on Wrangel Island and west Chukotka, Russia. Also reported from St Pierre and Miquelon (to France) as a non-breeder. Birds winter in eastern South America including Argentina, Uruguay, Paraguay and Bolivia after passing through the Greater and Lesser Antilles. Originally numbering in the hundreds of thousands to millions (1890s-1900s), the species was brought to near extinction in the early 1920s by hunting. It has not recovered With the current population estimated at 15,000 individuals.
The Canadian Wildlife Service estimates the current population of Buff-breasted Sandpipers at only 15,000 birds. Although they were formerly abundant, hunting brought the population close to extinction in the early 20th Century. This species' restricted range, with much of the population remaining in vulnerable areas, leaves it at risk. Human development in its range has increased disturbance and brought more predators, both of which are significant threats to this species. Habitat loss on the wintering grounds in Argentina and Bolivia has also contributed to their decline. The Buff-breasted Sandpiper is on the watch list of Partners in flight.

Buff-breasted Sandpipers eat mostly insects.

It is difficult to monitor, as it is not faithful to breeding sites (and possibly not to wintering sites), but data from North American migration sites suggests that declines are continuing. Immediate threats are the matter of some conjecture. The breeding grounds may be affected by habitat loss and degradation and environmental contaminants. Previously, ongoing declines were attributed to widespread and continuing destruction of grasslands in the wintering range, but there seems little evidence to support this, although environmental contaminants may be playing a part there. It appears to depend heavily upon intensive grazing by livestock. [conservation status from birdlife.org]

Groups of males form leks, or display grounds in the tundra breeding areas. Leks are typically fairly dense, but these birds have large display territories, up to 8 acres in size, so the entire lek may spread across a large area. Typical Buff-breasted Sandpiper leks are made up of 10 or fewer males. Females come to the leks where the males display their light underwings, one wing at a time. They mate on the lek, and the female leaves. The male provides no parental care. The female finds a spot on the ground, often on a moss hummock near water. There, she scrapes out a shallow depression and lines it with leaves, sedge, moss, or lichen. She incubates four eggs for 23-25 days. The young leave the nest within a day of hatching. They feed themselves, but the female tends them. The young begin to fly at 16-20 days.

A western Arctic breeding species, which migrates mainly through North American interior to winter quarters in southern South America (Paraguayan chaco and Argentine pampas). Small numbers diverge in Canada from main route and pass south down western side of Hudson Bay and across Great Lakes to New England states between Massachusetts and New Jersey, where occurs sparingly August-September. This minority passage believed to be origin of transatlantic vagrants. British and Irish records heavily concentrated in western areas, with vast majority in autumn, which suggests less successful than some other Nearctic waders at overwintering in Old World. However, 4 African records all in winter: Egypt, February 1928; Tunisia, December 1963; Sierra Leone, November 1973; Kenya, December 1973.