Sabine's Gull (Xema sabini)

"I have thought it remarkable that these birds seldom shun the fishermen, while towards any one bearing the semblance of a gunner they act with extreme caution. Although loquacious when congregated, they are, when separated, quite silent, especially when on wing. In squally and rainy weather they skim low over the water or the land, always against the wind. They are very tenacious of life, and often, when wounded, revive after you had considered them incapable of breathing. The instant they are caught they are wont to mute and eject the contents of their stomach, as well as when suddenly compelled to take to wing, or when pursued by predaceous birds. In particular states of the weather they appear at a distance much larger than they really are, and, on such occasions, they also seem much nearer, so that the gunner is greatly deceived, and may shoot at them when too far off."

John James Audubon (1840) in Birds of America, Vol. VII.


Taxonomy

Monotypic

Named after the English scientist/soldier Edward Sabine, who first discovered the species nesting amongst Arctic Terns on some rocky islands (later named the Sabine Islands) lying off the west coast of Greenland. Also known as Fork-tailed Gull but this name has fallen into disuse because of potential confusion with Swallow-tailed Gull.


Adult molting into basic plumage. Off California in July. Photograph copyright of Angus Wilson©.
 

Identification

A very attractive mid-sized gull (slightly smaller than a Common Black-headed Gull). Identification is relatively straight forward although there is often confusion with juvenile Black-legged Kittiwake, especially in poor light. Has a very boyant tern-like flight. In fact, at a distance Sabine's Gulls are more likely to be mistaken for Arctic Terns than Kittiwakes. This is due in large part to the very rapid wing beats and bouncing flight. Often encountered on the water in small rafts, sometimes in association with other species (Phalaropes, small shearwaters, storm-petrels etc). Will investigate the wake of boats but tends not to come in close or take chum materials. Sometimes Sabine's Gulls will fly directly up the wake and then slowly overtakie the boat affording wonderful views by both parties. The relatively long wings are especially evident in swimming birds which seem to ride higher in the water than Kittiwakes.

Sabine's Gull is unique amongst gulls in having a complete pre-breeding molt in the winter quarters followed by a partial post-breeding molt in the late summer. Immatures retain juvenile plumage during the first autumn on the wintering grounds. First-winter birds undergo a full molt in late winter/early spring and normally remain on the wintering grounds while adults travel north. These birds resemble basic-plumaged adults except that the bill generally lacks the yellow tip, the white primary tips are reduced and there may be traces of a black tail band. Attains adult-type plumage by its second winter.

Adults in alternate (breeding)-plumage have a solid black hood and neutral gray rather than brown inner wings and mantle. The black bill has a yellow tip, but this is hard to see at any distance. The legs are black. The iris is brown. The orbital ring and insides of mouth are red or vermillion.

Juveniles (July to December) have pale brown upperparts, closer views reveal a delicate patterning to the inner wing coverts, scapulars and mantle feathers. Each feather is gray-brown with an off-white trailing edge that is separated by a dark bar. The nape, ear coverts, crown and sides of the breast are uniform gray brown making the small head appear dark at any distance. The bill is mostly black but many have some horn color at the base of the lower mandible. Juveniles may give a tern-like call.


Adult molting into basic (winter) plumage. Dusky shading over the nape and ear coverts. The yellow tip to the peg-like black bill is visible here. Off California in July. Photograph copyright of Angus Wilson©.
 

Where and When

Breeds on coastal wet tundra (meadows and salt-grass flats) in the arctic. The breeding range is circumpolar including northern and western Alaska, arctic Canada, northern Greenland, Spitzbergen and across northern Siberia.

Outside the breeding season, Sabine's Gulls are essentially pelagic. In the Pacific greatest numbers are found in the eastern Pacific between southern Baja California and central Chile. In the Atlantic, concentrate in the tropics. Frequently encountered on migration along the continental shelf edges of North America (most numbers in Pacific), Europe and Africa. In California, spring migration peaks in early May while fall migration is more drawn out (late July to early November). Although large numbers pass offshore, few birds are seen from land and occur most commonly in a band between 10 and 100 miles from land.

Birds from eastern Canada and Greenland may use the rich feeding grounds of the Grand Banks off Newfoundland as a staging ground before migrating south towards Africa. John James Audubon wrote in his Birds of America:
"In the course of a voyage from Pictou in Nova Scotia to Hull in England, lately performed by my friend Mr. Thomas MacCulloch, he saw great numbers of this species when more than a hundred miles off Newfoundland. They flew around the ship in company with an almost equal number of Ross' Gull".

Peak numbers in Europe are thought to occur when North American birds are pushed eastwards across the North Atlantic by northwesterly or westerly weather systems (Hoogendoorn, 1995). More details of European records can be found here. Several birds blown inland by storms have been observed feeding almost exclusively on insects - perhaps reliving their experiences on the tundra?
 

Photographs on the web

Adults:

Phenomenal shot of an alternate-plumaged adult in flight. Taken by Brian Patteson in June.

Juveniles:

Juvenile in flight Photo by Jeff Blincow.
A very crisp shot showing the dorsal surface of a juvenile in flight. Photo taken by Rudy Offereins on the island of Terschelling in the Netherlands on 12th October.

Dorsal view showing pattern and shape of tail. Photo taken by Brian Patteson in September.

juvenile (rather fuzzy image) and a ventral view of the same juvenile. Both photos by Cameron Eckert.
 

Literature

Abraham, D.M. and Ankney, C.D. (1984) Partitioning of foraging habitat by breeding Sabine's Gulls and Arctic Terns. Wilson Bull 96: 161-172.

Hoogendoorn, W. (1995) [Multiple-day records of Sabine's Gull in the Netherlands] Dutch Birding 17: 15-21.

Grant, P.J. (1986) Gulls: A guide to identification. 2nd edition. Academic Press.

Vinnecombe, K.E. (1971) Sabine's Gull hawking flying insects inland. British Birds 64: 503-504.



Copyright © 2002 All rights reserved. Angus Wilson
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