Surfbird Life History

Habitat

Habitat ShorelinesSurfbirds nest in rocky tundra at higher elevations in arctic mountains. This habitat is very dry and supports only smaller vegetation such as lichens, some mosses, dwarf shrubs, mountain avens, black oxytrope, pincushion plant, and sometimes sedges in moist patches. Surfbirds use steep slopes and ridges at or near mountain summits, and seldom nest near wooded landscapes. They nest as low as 500 feet and as high as 6,000 feet elevation, but sometimes fly to lower elevations to forage when nesting. On those occasions, they may visit lake shores or coastal mudflats. Once young fledge, they may accompany adults to coastal feeding areas before beginning migration. Outside the short nesting season, Surfbirds are habitat specialists in rocky coastal environments of the Pacific, including islands and reefs. They rest and sometimes forage on adjacent beaches and tidal flats as well, but mostly they forage on rocky substrates. Back to top

Food

Food Aquatic invertebrates

Surfbirds consume a great variety of marine life as well as insects. On the breeding grounds they eat whatever insects (and their eggs or larvae) they can find, running along like plovers until they detect prey, then gleaning it from the ground or vegetation, or pouncing quickly to pick it up in the bill. They often eat flies (especially crane flies), beetles, bees, wasps, butterflies, and moths. During the nonbreeding season they eat mostly intertidal invertebrates, especially barnacles, snails, and bivalve mollusks, on rocks. They take prey by walking steadily along the rocks, grasping a prey item in the stout bill, and using the legs to dislodge it from the rock with a series of strong yanks. They sometimes peck or twist to loosen the animal before pulling it free. They occasionally hammer into shellfish, as turnstones or oystercatchers do, but typically swallow prey whole, shell and all. Unlike turnstones, Surfbirds do not often eat limpets, as their bills—well suited for gripping small mussels and barnacles—lack the chisel-like tip of the turnstone’s bill. When eating fish eggs, Surfbirds peck rapidly, much like a chicken. They also probe into sand, mud, algae, and wrack in search of prey, sometimes running back and forth with the waves like Sanderlings when feeding on mole crabs on the beach. Their prey includes straight horse mussel, dwarf mussel, purple mussel, blue mussel, California mussel, acorn barnacle, gooseneck barnacle, wide lacuna, puppet margarite, southern periwinkle, Sitka periwinkle, checkered periwinkle, carinate dove shell, Pacific mole crab, and littoral woodlouse. Surfbirds also consume algae (genera Fucus, Ulva, and Rhodomela).

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Nesting

Nest Placement

Nest GroundNests are set on sloped ground in alpine tundra.

Nest Description

Nest is a scrape lined with lichens and sometimes mountain avens or other flowering plants.

Nesting Facts

Egg Description:Eggs buff with buffy, reddish, or dark brown markings which are usually concentrated at the larger end.
Condition at Hatching:

Covered in down, eyes open, and able to feed itself on hatching.

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Behavior

Behavior Ground Forager

Male Surfbirds display in flight over the breeding territory, like many shorebirds. They fly 100 feet or more above the territory on trembling wings, breaking the flight to glide and sing. Sometimes they orient into the wind and hover above the territory to sing. On descending, they may hold the wings bowed downward. Unlike most other shorebirds, their display flight path is linear rather than circular. During courtship, males sometimes chase females in flight, who may respond in kind; then they land together, both stretch the wings skyward and hold them for a moment. One report of ground-based displays mentions mutual feeding and preening, and another describes a pair “leapfrogging” in fluttery flight over each other. In Alaska, pairs sometime join feeding aggregations of several dozen individuals, and it is not unusual to see groups of 3–4 adults feeding in the same area peaceably. Male and female remain together through chick-hatching, and family groups appear at lower elevations. During the nonbreeding season, Surfbirds sometimes squabble with each other where food is concentrated (such as at a beach with fish eggs), and they regularly chase smaller shorebird species while feeding on rocks. However, when not feeding, Surfbirds roost together with Black Turnstones and Rock Sandpipers in tight flocks without conflict.

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Conservation

Conservation Low Concern

Partners in Flight estimates the global breeding population at 70,000 individuals and rates the species a 12 out of 20 on the Continental Concern Score, indicating a species of relatively low conservation concern. Surfbird breeding habitat in Alaska is currently on largely protected public lands. The species’ dependence on rocky shorelines in the nonbreeding season, however, makes it especially vulnerable to marine oil spills and coastal disturbance. The impacts of climate change on habitats and food resources, particularly those resulting from rising sea levels, are also of concern for the conservation of Surfbirds.

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Credits

Andres, B. A., P. A. Smith, R. I. G. Morrison, C. L. Gratto-Trevor, S. C. Brown, and C. A. Friis (2012). Population estimates of North American shorebirds, 2012. Wader Study Group Bulletin 119:178–194.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Senner, Stanley E. and Brian J. McCaffery. (1997). Surfbird (Calidris virgata), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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