- Chroicocephalus genei
Length 42–44 cm, (16½-17¼ in) wingspan 90-102 cm
The Slender-billed Gull is a medium-small size gull. The head is white all year; the bill is dark red in summer, and mid-red in winter; the head and bill have a distinct elongated, tapering appearance, and it also appears long-necked. The legs are dark red, and the iris is pale yellow. The wings are pale silvery grey above, with a white stripe and black tips on the outer primaries; the outermost primaries are white below, and the central primaries blackish below. In summer, the breast is commonly tinged pink. This bird takes two years to reach maturity, as usual in Chroicocephalus gulls. First-winter birds have a black terminal tail band, and mottled brown areas in the wings; the bill and legs are yellowish at first, darkening to orange-red by the following spring.
Black-headed Gull is only slightly smaller, and shares the same wing pattern; it differs in having a brown hood in summer, and retaining a prominent dark smudge on the ear coverts in winter (young and some adult winter Slender-billed Gulls may show a faint dark smudge, but never a strong one). It is also more compact in shape, without the elongated bill, head and neck profile, and has a dark brown iris. First-winter Black-headed Gulls have a similar wing pattern, but the brown mottling is darker and more obvious.
Breeds very locally around the Mediterranean, north Africa (south to Mauritaina), the Black and Caspian Seas, and the northwestern Indian Ocean east to Pakistan, on islands and coastal lagoons. Most of the population is somewhat migratory, wintering further south in north Africa, Arabia, and India. A few birds have wandered to western Europe (north to southern England), and a stray individual was reportedly seen on Antigua, April 24, 1976 (AOU 2000).
As with other species of Chroicocephalus, it was formerly placed in the genus Larus.
This rather uncommon gull breeds in colonies, nesting on the ground and laying up to three eggs. Like most gulls, it is gregarious in winter, both when feeding or in evening roosts. It is not a pelagic species, and is rarely seen at sea far from coasts. It is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
The diet includes a substantial proportion of shrimps and plankton, from which it obtains the pink pigment in its breast feathering.
The scientific name of this bird commemorates the Italian naturalist Giuseppe Gené.
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2017. The eBird/Clements checklist of birds of the world: v2017, with updates to August 2017. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
- Olsen, K. M., & Larsson, H. (2003). Gulls of Europe, Asia and North America. Helm ISBN 978-0-7136-7087-5
- BirdForum Opus contributors. (2023) Slender-billed Gull. In: BirdForum, the forum for wild birds and birding. Retrieved 1 December 2023 from https://www.birdforum.net/opus/Slender-billed_Gull
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