Identification
The slender-billed gull is a mid-sized gull measuring 37 to 40 cm in length with a wingspan of 90 to 102 cm, making it slightly larger than the familiar black-headed gull. Its most distinctive feature is its elongated, tapering head and notably slender dark red bill, which give the bird a characteristically stretched appearance enhanced by its long neck. The plumage is predominantly pale grey on the body, with a white head and breast, black tips to the primary wing feathers, and dark red legs. The iris is yellow, and in summer breeding plumage, the breast shows a faint pink colouration. Unlike the black-headed gull, this species does not develop a black hood in summer. Immature birds in their first year can be distinguished by a black terminal tail band and dark areas on the wings; the species takes two years to reach full maturity.
Range & habitat
The slender-billed gull breeds very locally around the Mediterranean Sea and in lagoons and lakes bordering the northwestern Indian Ocean, with populations found in countries including Pakistan. Breeding sites favour islands and coastal lagoons with minimal human disturbance and predators—conditions that enabled a successful colony discovered in a mountain lake in Algeria in 2010 to achieve exceptional hatching success. Most of the population is migratory, wintering further south along the coasts of North Africa, the Middle East, and India in estuaries and bays. The species feeds in deltas, marshes, grasslands, and occasionally on landfill sites. It is not pelagic and is rarely seen far from land, preferring coastal and inland waterway habitats throughout its range.
Behaviour & diet
The slender-billed gull is an adaptable forager, with approximately half its diet consisting of fish. It hunts by flying a few metres above the water surface and diving when suitable prey is spotted. The bird also probes in mud with its slender bill to capture marine invertebrates and occasionally catches insects in flight. This species is colonial, nesting on the ground in loose groups and laying up to three brown-spotted white eggs in simple scrapes sparsely lined with feathers and vegetation. Incubation lasts approximately 25 days, with young fledging after another 25 days. Like most gulls, it is highly gregarious in winter, gathering both at feeding sites and at evening roosts, though it maintains its non-pelagic character throughout the year.
Best time & places to see it
Breeding birds can be found around Mediterranean lagoons and islands during the breeding season, with the species present year-round in some locations. Winter months offer the best opportunity to observe larger concentrations as migratory populations gather in estuaries and bays across North Africa and India. The species remains uncommon throughout its range, making sightings a rewarding find for dedicated birdwatchers. Coastal wetlands, river deltas, and sheltered bays are the most reliable habitats to search.
Photography tips
The slender-billed gull's elegant proportions and distinctive bill shape reward careful photography. The bird's pale plumage and yellow iris stand out clearly in good light, while the delicate pink wash on the breeding bird's breast is a subtle detail worth capturing during summer visits. Photographing birds in flight reveals the black primary tips effectively. Patience is essential given the species' uncommon status and wariness—position yourself discreetly at roost sites or feeding areas during winter gatherings for the best opportunities to document this elegant but elusive gull.
