Aves | Ciconiiformes
Southern Ocean Mollusc Database (SOMBASE). 2011. (Ref. 87340)
Size / Weight / Age
Common length : 20.0 cm TL male/unsexed; (Ref. 87784); max. published weight: 45.00 g (Ref. 87784)
Climate / Range
Northeast Pacific, Southwest Atlantic and Antarctic Atlantic: Subtropical to polar.
Small (ca. 20 cm long, <45 g); brightly colored during breeding season; while at sea, wear counter shade coloring of white underparts, tail, neck and face, gray mantle, and black eyepatches; laterally-flattened legs, lobed feet, and exceptionally waterproofed plumage (heavy at belly and breast) modified for aquatic life (Ref. 87784). Shorebird species that inhabit oceanic waters up to 75% of the time. Spend up to 9 months of the year swimming on the open ocean. Body modified for aquatic life; surface swimmers by paddling. Pelagic. Feeds on almost anything found on the water surface that is small enough to ingest, including crustaceans, hydrozoans, molluscs, polychaetes, gastropods, insects, small fish, fish eggs, seeds, sand, and plastic particles; main diet of planktivores; at sea, specialize on copepods, euphausiids, and amphipods < 6mm x 3 mm. Peck rates as high as 180/min. Attracted to the feeding activity of forging gray whales (Eschrichtius robustus) in the Bering Sea where they feed on mud plumes from disturbed sediments that rise to the surface; several species of benthic amphipods are eaten that would normally not be found on surface waters. In the Gulf Steam off the east coast of North America, small numbers found at floating mats of the marine algae, Sargassum where they feed on associated zooplankton. Draws prey to the surface with feverish, toy-like spinning behavior; spinning can draw water up to the surface from 0.5 m depth. California Current off western North America, the Humboldt Current off western South America, and the Benguela Current off West Africa are important foraging areas. Feed at convergences, drift lines, fronts, slicks, thermal gradients, and upwellings where food is concentrated on the surface. Flocks at these feeding areas was recorded at an estimated high of 2 to 3 million migratory individuals at a single upwelling near Mount Desert Rock off the coast of Maine, NW Atlantic. Numerous in the California Current off western coast of United States from May to March and joined by migrating Red-necked Phalaropes from July to November, and together winter off the western coast of South America; most in this area of the Pacific congregate by the Humboldt Current. Those wintering in the Humboldt Current come from breeding populations in North America and possibly Siberian Arctic; found in the Galapagos Is., and as far south as southern tip of Chile. From Nearctic breeding populations flocks in the western Bay of Fundy; movements south from there and their wintering destinations still poorly known. Circumpolar breeding distributions in the Subarctic and Arctic, and generally only breed ashore. Brightly colored during breeding season. Do not nest colonially. Vulnerable to anthropogenic alterations of marine environments and climate change supported by the record disappearance (declines or relocation) of millions of migrating birds from Japanese waters during spring, from staging flocks in the western Bay of Fundy, and from off the coast of the northwestern United States (Ref. 87784).
IUCN Red List Status (Ref. 114614)
CITES status (Ref. 94142)
Threat to humans
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Estimation of some characteristics with mathematical models