Chroicocephalus genei (Brème, 1839)

Common Name and Size

Chroicocephalus genei, commonly known as the slender-billed gull, measures 37 to 40 cm (14.6 to 15.7 in) in length, with a wingspan ranging from 90 to 102 cm (35.4 to 40.2 in). It is slightly larger than the black-headed gull, which it resembles, but does not develop a black hood during the summer breeding season.

Plumage Coloration

This species has a pale grey body, white head and breast, and black tips on its primary wing feathers.

Head and Bill Structure

Its head and dark red bill have an elongated, tapering shape, and the bird has a distinctly long-necked appearance.

Appendage and Iris Coloration

Its legs are dark red, and its iris is yellow.

Summer Breeding Plumage

During the summer, the breast takes on a faint pink colouration.

Maturation Period

Like most gulls, the slender-billed gull takes two years to reach full maturity.

First-Year Immature Appearance

First-year immature individuals have a black terminal band on the tail and dark patches on the wings.

Breeding Range

The slender-billed gull breeds in lagoons and lakes around the Mediterranean Sea, and in similar habitats in countries bordering the northwestern Indian Ocean.

Algerian Breeding Colony Observation

In 2010, a successful breeding colony was discovered on an island in a mountain lake in Algeria; the lack of predators and human disturbance allowed over 98% of the colony's eggs to hatch.

Overwintering and Foraging Habitats

This species overwinters on coastal estuaries and bays, and forages for food in deltas, marshes, and grassland.

Feeding Behavior

It is one of several gull species that will feed at landfill sites.