Long-tailed Skua

Long-tailed Skua

Summary:

Profile Long-Tailed Skua
[order] Charadriiformes |

[order] Charadriiformes | [family] Stercorariidae | [latin] Stercorarius longicaudus | [UK] Long-Tailed Skua | [FR] Labbe à longe queue | [DE] Kleine Raubmöwe | [ES] Págalo rabero | [IT] Labbo codalunga | [NL] Kleinste Jager

Kleinste Jager determination

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The Long-tailed Jaeger is the smallest jaeger, with a slender body and narrow wings. During the breeding season, the adult has long central tail feathers that extend 5-10″ beyond the rest of the tail, but from August to November, these are often broken or missing. The breeding adult has grayish upperparts contrasting with darker secondaries, a whitish head and underparts, a blackish-brown cap, and a yellow cast to the sides of its neck. The underwing lacks a white patch. Dark phases are very rare in adults. The non-breeding adult (November to March) has a cap flecked with white and gray, and underparts (except the wing) barred with brown and white. It lacks long central tail feathers. Juveniles and immatures have both light and dark phases, but light is more common. In general, they have brown and white barring on underwing coverts, flanks, and uppertail and undertail coverts. In other parts of the world, jaegers are known as skuas.

Little is known about their diet at sea, but it includes fish, crustaceans, and polychaete worms. During the breeding season, they eat mostly lemmings and voles.

Stercorarius longicaudus breeds in Greenland, Svalbard, Fennoscandia and arctic
Russia, with Europe accounting for less than a quarter of its global breeding range.
Its European breeding population is relatively small (br>The Long-tailed Jaeger is the most abundant and widespread jaeger in the Arctic. Although local breeding populations fluctuate with the food supply, overall numbers in North America appear stable.

Breeding birds are found both near the coast and farther inland on sparsely vegetated, dry Arctic tundra. At other times of the year, Long-tailed Jaegers are highly pelagic, usually at least ten miles from land. They often spend time on offshore banks, in areas with schools of small fish near the surface, and near commercial fishing vessels.


This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km². It has a large global population estimated to be 100,000-500,000 individuals (del Hoyo et al. 1996). Global population trends have not been quantified, but populations appear to be stable (del Hoyo et al. 1996) so the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]


Long-tailed Jaegers for monogamous long-term pair bonds. Both sexes build the nest, a shallow depression often on a slightly raised area. They are limited to 2 eggs because, while incubating, they hold an egg between one foot and its corresponding brood patch. Females incubate more than males. Chicks stay in the nest 1-2 days after hatching. One parent, usually the female, remains near the nest while the other one forages. Typically, the male brings food back, regurgitates, and the female feeds the young. Young often remain with their parents for 1-3 weeks after fledging, which occurs at 22-27 days.

Migratory, but details imperfectly known. Identification of immatures and winter-plumaged adults especially difficult; hence more spring than autumn passage records. Paucity of inshore records anywhere indicates this to be the most highly oceanic skua. Rare visitor or vagrant inland south of breeding range in west Palearctic. Wintering areas still poorly known; evidently all in southern hemisphere since only exceptionally found north of Equator, December-March.
The earliest autumn migrant on average of the 3 small Palearctic skuas, and the one showing the most longitudinally restricted Atlantic passage, mainly 25-45°W. Large-scale departures from breeding grounds in August, with exodus completed early September; pelagic passage in North Atlantic from end July, with August-September main period there. Begins to reappear in North Atlantic in April, with main passage during May. Spring migration evidently quicker and more concentrated than in autumn. Arrives Greenland from late May; on breeding grounds in Canadian Arctic, Spitsbergen, and Russia from first half June.

Specification

  1. Measurements
  2. spanwidth min.: 105 cm
  3. spanwidth max.: 117 cm
  4. size min.: 48 cm
  5. size max.: 53 cm
  6. Breeding
  7. incubation min.: 23 days
  8. incubation max.: 25 days
  9. fledging min.: 24 days
  10. fledging max.: 26 days
  11. broods 1
  12. eggs min.: 1
  13. eggs max.: 2
  14. Conservation Status
  15. Kleinste Jager status Least Concern
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