Saunders's Gull

The Saunders's gull, or Chinese black-headed gull, is a diminutive member of the gull family Laridae, notable for its small stature, with a length of merely 33 cm. This species is distinguished by its striking black hood and nape during the breeding season, contrasting with its otherwise pale plumage, grey wings, and a distinctive narrow black band on the tail. The legs and bill are black, and the bird has a rather compact body shape.

Identification Tips

In breeding plumage, adults exhibit a black hood and nape, which is a key feature for identification. The wings are pale grey, and the narrow black tail band is quite prominent. The bill and legs are black. During the non-breeding season, the hood and nape become mottled grey, and the wings show white tips with black markings on the primaries.

Habitat

The Saunders's gull favors estuarine waters and intertidal marshes, particularly saltmarshes dominated by seepweed (Suaeda glauca), where it breeds.

Distribution

This species is found across various regions in Asia, including China, Hong Kong, Japan, North and South Korea, Macau, Russia, Taiwan, and Vietnam. It breeds in eastern China and the west coast of Korea and overwinters in the southern parts of its range.

Behaviour

The Saunders's gull is known for its unique foraging technique, flying about ten meters above the ground and swiftly descending upon prey such as mudskippers, crabs, fish, and worms. It also engages in kleptoparasitism, stealing food from other bird species. With only partially webbed feet, it is not adept at swimming and prefers to stay on land, moving with the tide along the beach.

Breeding

Breeding occurs in saltmarshes, with a simple scrape in the ground serving as a nest. The species is monogamous, with pairs defending their territory. Clutch size ranges from two to three eggs, laid in May, and incubation lasts approximately 22 days. Both adults and fledglings migrate to winter quarters in October.

Conservation status

The Saunders's gull is classified as Vulnerable by the IUCN, with an estimated population of 21,000 to 22,000 individuals that appears to be declining. The primary threat to this species is habitat degradation, particularly the loss of saltmarshes due to aquaculture development and the invasive spread of smooth cordgrass (Spartina alterniflora). Disturbance leading to increased predation on eggs and chicks is also a significant concern.