Sabine's gull (Xema sabini)
Sabine’s gulls breed in the sub arctic and high arctic regions of North America and Russia, as well as on Greenland and in Svalbard. It is a dark-headed gull with a slightly forked tail. Sabine’s gulls nest on the ground in moss and grass covered tundra areas, placing their grass and sea-weed lined nests in shallow depressions close to water.
The sabine’s gull is a dark-headed gull with a slightly forked tail. The sexes are similar in appearance. In flight and in its general body form it resembles a tern, being more slender than the kittiwake and having proportionally more narrow and longer wings. Adults are approximately 33 cm long and weigh 150-210 g. During flight the wings are raised and lowered more than in the kittiwake. In summer plumage the head is a dark slate grey. The front part of the back and wings are grey, while the outer wing flight feathers (primaries) and wing coverts are black with white tips. The rear-edge of the wings, the undersides of the wings, the belly and tail are white. The bill has a yellow tip and black base. The legs are black. The winter plumage is similar to the summer plumage, but the head is partly white and the neck has black dappling. Juveniles have a grey-brown head, back and front part of the wings. The under-parts are white and the tail is white with a black band at the edge. The black markings of the wings make it easy to confuse young sabine’s gulls with a young kittiwake. Juveniles may also be confused with young Ross' gulls. The sabine’s gull call is a grating "kree".
Sabine’s gulls breed in the sub arctic and high arctic regions of North America and Russia, as well as on Greenland and in Svalbard. It is often considered monotypic, but four sub-species are recognized. The Svalbard population belongs to X. s. palearctica. In Svalbard the Sabine’s gull is a rare, but regular breeder. Moffen, north of Spitsbergen, is one of few localities where the species has bred regularly in the last decades. The species is thought to have bred regularly in Kongsfjorden early in the 20th century. However, the last confirmed breeding in this area was in 1923. Single nests have been found in other areas such as on Lågøya, Kvitøya and in Isfjorden, and additional breeding sites may well exist, but the number of breeding pairs is nonetheless very low. The Sabine’s gull may be observed occasionally in the surrounding waters of Svalbard during the summer. This species spends the winters in oceanic waters of the southern hemisphere along the south-west coast of South America and off southwest Africa.
Sabine’s gulls nest in tundra areas, especially preferring small islands where fresh water is available not too far from the sea. Outside the breeding season this gull species is pelagic (found out at sea). Sabine's gulls usually nest in or near colonies of arctic terns, which provide protection from predators. It defends its nest against intruders, but is less aggressive than the arctic tern. The diet of the Sabine’s gull is thought to consist of small fish and invertebrates. But, it also occasionally takes small birds, eggs of arctic terns and carrion.
Life history and reproduction
Sabine’s gulls nest on the ground in moss and grass covered tundra areas, placing their grass and sea-weed lined nests in shallow depressions close to water. The two to three eggs are olive-brown or greenish with dark speckles. They hatch after 23-26 days in which both parents share incubating duties. The chicks leave the nest a few hours after hatching and follow their parents to coastal areas or fresh water ponds. The chicks are fed by both parents, mainly on insects. Most one-year old birds probably stay at southern latitudes throughout their first summer.
Management status and monitoring
Information is scarce regarding the habitat requirements and feeding habits of sabine’s gulls in Svalbard, and little is known about breeding biology and their migratory patterns. Sabine’s gulls are one of the rarest breeding birds in Svalbard, but the species probably reproduces more or less annually in low numbers (ten to fifty pairs) in the archipelago. The world population is thought to be approximately 10,000 pairs. The population trend inSvalbardis unknown. The population that bred in Kongsfjorden was never large, and other breeding records are only of single pairs only, except for the birds breeding on Moffen. The Sabine's gull is named after the British general and scientist Sir Edward Sabine, who discovered the species in 1818 on the west coast of Greenland.
MOSJ indicators (Environmental Monitoring of Svalbard and Jan Mayen):
Awaiting results from MOSJ…