Sabine's Gull

The Sabine's gull, also known as the fork-tailed gull or xeme, is a diminutive and graceful seabird, the sole occupant of the genus Xema. With a body length ranging from 27 to 33 cm and a weight between 135 to 225 grams, it is a small gull with long, slender wings spanning 81 to 87 cm. The species is distinguished by its black bill with a yellow tip, and a striking wing pattern that captivates the observer.

Identification Tips

Upon sighting, one can readily identify an adult Sabine's gull by its pale grey back and wing coverts, contrasting with black primary flight feathers and white secondaries. The white tail is elegantly forked, and during the breeding season, the male's hood darkens. Juveniles and young birds share the tricoloured wing pattern but with brown replacing the grey, and their tails are marked by a black terminal band. It takes two years for juveniles to achieve full adult plumage.

Habitat

Sabine's gulls are birds of the Arctic tundra and coasts, where they breed in colonies. They are pelagic outside the breeding season, venturing into open seas.

Distribution

These gulls have a circumpolar distribution in the Arctic regions of North America and Eurasia. They migrate southwards to the Pacific Ocean and the cold waters nourished by the Humboldt and Benguela Currents off the coasts of South America and southwestern Africa, respectively. They are also known to make stops along the US West Coast and various island chains during migration.

Behaviour

Sabine's gulls exhibit a unique molt pattern, with fledged birds retaining their juvenile plumage until reaching wintering grounds. Adults undergo a complete molt in spring before migration and a partial molt in autumn upon return. They are also known for their high-pitched and squeaking call.

Song & Calls

The call of the Sabine's gull is a very high-pitched and squeaking sound, quite distinctive from other gull species.

Breeding

These gulls breed in colonies on coasts and tundra, laying two or three spotted olive-brown eggs in a ground nest lined with grass. The male's hood darkens during the breeding season, signaling readiness for courtship.

Similar Species

The Sabine's gull is almost unique within the gull family due to its notched tail and black bill, shared only with the swallow-tailed gull of the Galapagos. However, they are not closely related, with the ivory gull being the closest relative of Sabine's gull.

Diet and Feeding

The diet of Sabine's gull varies with the season. During the breeding season, they feed on a variety of prey including beetles, springtails, craneflies, mosquitoes, midges, flower flies, molluscs, insects, arachnids, water bugs, larvae, crustaceans, fish, and occasionally nestling birds or eggs.

Conservation status

The Sabine's gull is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of widespread decline.