Birds of the World |
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COAST BIRDS |
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TRAITS |
Charadriiformes / Lari - Jaegers, Skuas |
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Shorebirds, Charadriiformes Pterocli - Sandgrouse Charadrii - Shorebirds Families: Seedsnipe, Plains-wanderer, Thick-knees, Plovers and Lapwings, Oystercatchers, Ibisbill, Stilts and Avocets, Painted Snipe, Jacanas, Magellanic Plover, Sheathbills, Sandpipers, Phalaropes Lari - Gulls, Terns, Skimmers Families: Crab Plovers, Pratiincoles and Coursers, Jaegers and Skuas, Gulls, Terns, Skimmers Alcae - Auks Families: Auks |
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Species: |
Pacific Golden-Plover, Southern Lapwing, Blackish Oystercatcher, American Black Oystercatcher, Silver Gull, Western Gull, Heermann's Gull, Lava Gull, Swallow-tailed Gull, Kelp Gull, Dolphin Gull, South American Tern |
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Sanderling, Willet, Piping and Semipalmated Plovers, Masked, Southern, Red-wattled, and Northern Lapwings, White-tailed Plover, Eurasian, Blackish, and American Black Oystercatchers, Pied Stilt, Northern and Wattled Jacanas, Snowy Sheathbill, Willet, Sanderling, Western Sandpiper, Red Phalarope, Alaskan shorebirds, Laughing Gull, Forster's Tern, Black Skimmer, South Polar Skua, Bonaparte's Gull, Fairy Tern, Black Skimmer, Common Murre, Pigeon Guillemot, Klittliz's Murrelet, Black Guillemot, and Tufted Puffin |
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"Laridae" - Skuas, Gulls, Terns, and Skimmers. 106 species, 16 genera. Sibley and Monroe (1990) and the AOU include these groups (along with the Auks) in a single family (Family Laridae): Skuas/Jaegers (7 species) are gull-like with long, pointed and angled wings. They are swift predators often found in penguin colonies (and other near polar areas) and pirates of the high sea. Gulls (about 50 species) are similar in appearance. Smaller species tend to have a black head in summer. Terns (about 44 species) are slimmer with narrow wings and a pointed bill. Gull-like sea terns have a black cap in summer. Marsh terns are black in summer. Noddies are dark brown with a lighter cap. Skimmers are tern-like but are more robust with very long, dark wings and a modified lower mandible used to catch fish. There is some evidence that each group should be treated as a separate family as follows: |
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Family Stercorariidae - Jaegers and Skuas | ||||||||
8 (7) species, 2 genera (1 genus). Worldwide in all oceans - breeds at higher latitudes in both hemispheres (jaegers in the north, skuas in the south). Jaegers and Skuas are closely related to gulls but are now generally placed in their own family. There is a movement to call all members of the family skuas so you may see names both ways (e.g., Arctic Skua or Parasitic Jaeger, Stercorarius parasiticus). Jaegers/skuas are predatory seabirds and are oceanic species, but may be found along the seacoasts of all continents, especially in winter. They have long-pointed wings that are angled at the wrist. They are medium-sized birds - jaegers are generally smaller than skuas. They have a strong gull-like bill with a hooked tip. They have a prominent cere and their rhamphotheca is complex (more than one scale is found on the upper mandible). They have strong webbed feet with large claws that are strongly hooked (raptorial). They are generally dark - smaller species may be polymorphic. All have broad white flashes on their primaries. Skuas lack the longer central feathers found in adult jaegers. They have large caeca. Their pelvic muscles are AXY+. They are usually solitary outside the breeding season but may form small groups around prey species. While on land they are predatory (feeding on lemmings, birds, and other small animals) and at sea they obtain much of their food (up to 95%) by piracy (stealing fish from other birds) - kleptoparasitism. All aggressively pursue other seabirds (from terns to gannets) and larger skuas may kill birds as large as a Grey Heron. They chase their victims until they disgorge any food they have eaten or drop anything they are carrying. Larger species gather around colonies of alcids or penguins and prey on eggs and young. They have a variety of vocalizations. Most breed in coastal moors or tundra or on grassy islands. They nest on the open ground. Outside the breeding season most are pelagic. Most disperse during the winter. Three species are trans-equatorial migrants. One was sighted at the South Pole. Jaegers breed on the Arctic tundra and all but one of the larger skuas are found near Antarctica and the southern seas. They are monogamous and pair for life. They build a scrape and lay 1-2 eggs. Incubation lasts 23-38 days in smaller species, more than 30- days in larger species. The female tends the nest and is fed by the male. Jaegers fledge at 24-32 days, skuas fledge at 45-55 days. Jaegers are often difficult species to identify and remain off-shore in our area, They have not been recorded on Seabrook. |
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South Polar Skua, Stercorarius maccormicki, being chased by a Gentoo Penguin, Pygoscelis papua. Antarctica. Courtesy Anna Kate Hein. Click for a second image of the skua. Wiki ToL EoL |
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Banner - South Polar Skua (with Gentoo Penguin). Antarctica. | ||||||||
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