In late September a rare gull was seen at Cap Pelé. The east coast of New Brunswick is heavily birded in the fall because migration and fall storms often bring us a variety of rare birds. The Sabine's gull was one such species.
The Sabine's Gull (Xema sabini) is a tern-like gull. It is a high latitude holarctic pelagic species which occurs rarely inland. It is listed as a casual spring migrant to New Brunswick and rare in fall. Most reports have come from the Grand Manan area with fewer along the east coast. Our first record was from Indian Island, Passamaquoddy Bay in 1878. We have reports from 1966, 1972 and 1998. There was a pair of adults at Carleton Park, Fredericton, on 23 August 2004. We don't see this species every year but sightings are more frequent now, perhaps because we have many more knowledgeable birders in the field. The individual in this report was seen and photographed on 24 and 25 September, 2022.
The taxonomy of the Sabine's Gull is in debate. Although mostly placed in the 'Xema' genus, some place it in 'Larus'. The species seems to fall somewhere between gulls and terns although it is classified as a gull. Some list it as having 4 sub-species, others place it as monotypic (in one species).
The Sabine's Gull is 32 to 35.5 cm long and is striking in appearance. Both genders are similar. It is small and elegant and is a two-cycle hooded gull. Its bill is small and slender and is black with a yellow tip in breeding plumage, black otherwise. Its tail is moderately forked and when the bird is at rest the tail tip falls between P7 and P8 (slightly shorter than the wing projection). The Sabine's Gull has a remarkable and striking wing pattern. The leading edge of the upper wing surface is gray on the inner half and black on the outer half. Between these two patches is a large white triangle witch extends to most of the trailing edge. The underwing surface is whitish with black outer primaries. When a bird with wings with this pattern flies it makes a remarkable flashing motion. If you have seen it, you would not forget it. See photo below. In breeding plumage there is a black hood and black legs. Juveniles are dark scaly brown on the back, nape and wings.
Sabine's Gulls breed on the tundra in the far north. Their breeding grounds include Canada's arctic islands, the shorelines of Northwest Territories, Yukon and Alaska, Greenland, Spitzbergen and northern Siberia. Outside the breeding season the species is mainly pelagic. They migrate south along North America's west coast to winter off Mexico and South America where they winter in the Humboldt Current off Peru and Northern Chile. The eastern race migrates south along North America's east coast and heads over the Atlantic Ocean after they leave Atlantic Canada. Some winter in South Africa but it is not well known where others spend the winter.
Sabine's Gulls nest in a scrape in the tundra lined with grasses. One to three olive buff eggs are laid and incubated 23 to 26 days by both adults. The diet of this species includes fish and marine invertebrates. They feed by wading and pick up food from edges of pools. They also swim in circles in order to stir up food like phalaropes. They also run over mud flats and scoop up stranded fish.
The Sabine's Gull is unique in appearance and behaviour. It is the only member of its genus, 'Xema'. It is like no other gull and resembles both terns and gulls. As you can guess, it was named after a person, Sir Edward Sabine whose brother, Joseph, gave him the honour. Sir Edward (1788-1883) was an Irish astronomer, geophysicist, ornithologist and explorer. He must have found a few Sabine's Gulls in his travels.
Gulls are very interesting birds to study. They are so varied in appearance that they often fall into the realm of advanced birding. Never-the-less, they are very interesting and worth more careful study. If you ever find a Sabine's Gull, be sure to report it because it would be noteworthy.
