Surfbird

INTRODUCTION:
The Surfbird is now placed in the genus Calidris, following some passages through other genera such as Tringa and Aphriza, and unclear relationships with other species. But a molecular study suggests that the two species of knots, the Red Knot and the Great Knot, are its closest relatives with similar aspects of plumage.
The Surfbird winters along the Pacific coasts of the Americas and breeds in Alaska. Outside of breeding season, it shares its wintering areas with the Black Turnstone in the Northern Hemisphere, and the Ruddy Turnstone in the Southern Hemisphere. They have similar general behaviour.
The Surfbird is not globally threatened and the numbers are currently stable.

Peru

With Ruddy Turnstone

DESCRIPTION OF THE BIRD:
Biometrics:
Length: 23-26 cm
Wingspan: 55 cm
Weight: 133-250 g

The Surfbird in breeding plumage has mottled grey upperparts including head, mantle and upper scapulars, with chestnut and white edges. We can see several conspicuous, large, golden-buff oval patches on the largest, black-tipped scapular feathers. A narrow white wingbar is visible in flight. Uppertail and tail base are white, but there is a broad subterminal black band and a narrow terminal white band.

On the whitish underparts, lower breast and flanks show black chevrons. The underwing is mainly white with some greyish on primary coverts and leading edge.

Head, neck and upper breast are heavily streaked.
The short bill is dark with yellow/orange base of lower mandible and cutting edges of both mandibles. The eyes are dark brown. Legs and feet are yellow.

California

Bird moulting into breeding plumage with some visible chestnut feathers

The Surfbird in non-breeding plumage has plain slate-grey upperparts, head, neck and breast. On the underparts, the chin is whitish and the flanks are sparsely spotted dark.

California

Winter plumage

Male and female are similar.
The juvenile resembles non-breeding adult, but it has slightly browner upperparts, with most feathers showing buff fringes. The breast is mottled brownish whereas flanks and upper belly are finely spotted grey-brown.

RANGE:
The Surfbird breeds in C and S Alaska and W Yukon. It winters on the Pacific coasts of Americas, from SE Alaska, S to Strait of Magellan.

Resting birds

Seward, Alaska

HABITAT:
The Surfbird breeds on rocky ridges on mountain tundra above the treeline. Outside of breeding season, it is mostly seen on rocky oceanic shores and islands, but also on jetties and breakwaves.
During migration, it occurs sometimes on sandy beaches or mudflats during short stopovers. The winter range is very long and narrow, stretching among more than 17,500 kilometres, but it extends only a few metres above the tide line.

Ecuador

CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Surfbird gives squeaky, high-pitched chatter “chir chir chir chir” especially when feeding or in flight. We can also hear a shrill, plaintive whistle “kee-wee-ah” but this species is often silent.

BEHAVIOUR IN THE WILD:
The Surfbird forages on rocks usually covered with seaweeds in the intertidal area, and sometimes on adjacent sandy beaches.
It feeds on insects, molluscs and barnacles, but during summer on tundra, it feeds primarily on insects, spiders, snails and occasionally seeds.
On the coast, its diet includes mussels, limpets, snails, barnacles and crustaceans.
The molluscs are removed from rocks with quick sideways jerk of the head, thanks to the thick bill. It may sometimes probe in mud.
The Surfbird is often seen in small mixed-species groups with turnstones and sandpipers.

California

At the beginning of the breeding season, the Surfbird performs aerial displays over the nesting site, a long flight on fluttering wings while following a shallow arc. Then, it glides while uttering repeated calls or singing.
This species is territorial and probably monogamous. The pair forms on the breeding grounds.

The Surfbird is migratory and moves from the nesting areas in Alaska, S to Strait of Magellan, usually travelling along the American Pacific coasts. They leave the breeding grounds from July to mid-October, and return from early March to late April/mid-May.

The flight is swift with rapid, powerful wingbeats. It often performs fast fluttering flights between rocks.

Ecuador

REPRODUCTION OF THIS SPECIES:
The laying occurs between mid-May and early June. They nest at densities of 3 to 5 pairs/km².
The Surfbird nests on the ground, in a natural depression in rocky surface of high ridge surrounded by low vegetation. The nest is lined with pieces of dead leaves, lichens and mosses.

The female lays 4 buff-coloured eggs with dark spots. Both adults share the incubation during 22-24 days. The downy chicks leave the nest soon after hatching, and both parents tend them, but the young are able to feed themselves. They probably fledge one month after hatching.
Both adults and young are taken by red foxes, Falconidae of genus Falco, and skuas of family Stercorariidae. The eggs are taken by Arctic Ground Squirrels.

Ecuador

PROTECTION / THREATS / STATUS:
The Surfbird is generally described as uncommon. The breeding population is estimated to number 50,000/70,000 individuals. The overall population is slowly decreasing but the species is not globally threatened, and currently evaluated as Least Concern.

California

Bird moulting into winter plumage