Black-tailed Gull

The Black-tailed Gull, Larus crassirostris, is a medium-sized seabird with a distinctive black tail. It measures approximately 46 cm (19 inches) in length with a wingspan ranging from 126 to 128 cm (49.6 to 50.3 inches). The species exhibits yellow legs and a notable red and black spot at the end of its bill. Both sexes share the same plumage, though males are generally larger than females. It takes four years for this gull to attain its full adult plumage.

Identification Tips

When identifying the Black-tailed Gull, look for its yellow legs and the characteristic red and black spot on the bill. The black tail is a key feature, along with its medium size. The bird's call, reminiscent of a cat's meow, is also a distinctive identifier.

Habitat

This gull is native to the shorelines of East Asia, favoring coastal environments.

Distribution

The Black-tailed Gull is commonly found along the coastlines of the East China Sea, Japan, Manchuria, and the Kuril Islands. It is a vagrant to Alaska and North America and has been observed in the Philippines.

Behaviour

The Black-tailed Gull is known to follow ships and commercial fishing fleets, often scavenging for food. It is a colonial nester, with colonies forming in mid-April. The species is also known for stealing food from other seabirds.

Song & Calls

This gull is recognized for its cat-like call, which has earned it the nickname "sea cat" in Japan. It uses a variety of vocalizations for communication, including more than 10 different sounds. These calls serve various purposes, such as alarm signals, aggressive calls during attacks, and contact calls for intra-specific communication.

Breeding

The Black-tailed Gull is a colonial nester, with breeding colonies established by mid-April. Clutches of 2–3 eggs are laid by early June, with an incubation period of approximately 24 days.

Diet and Feeding

The diet of the Black-tailed Gull consists mainly of small fish, molluscs, crustaceans, scraps, and carrion. Studies of gull excreta have revealed a diet composition that includes fish, crustaceans, and land insects.

Conservation status

The Black-tailed Gull is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.