Larus saundersi

Male and female birds have similar body color. Black head and upper neck. Lower neck, upper back, shoulders, tail covering, tail feathers and lower body white. The lower back, waist, tertiary flight feathers and upper wing cover feathers are gray, and the leading edge and outer edge of the wing are white. The first to third primary feathers are white on the outside, grey or off-white on the inside with broad black edges and black tips, the inner primary feathers are grey with black spots on the tips, and the secondary feathers are grey with broad white tips. The upper and lower margins of the eyes have starlike white spots and are connected behind the eyes.
The winter feathers are roughly similar to the summer feathers, but the head is white with black spots behind the eyes and ears, and the crown is studded with light brown.
The young bird has similar winter plumage to the adult bird, but the back is slightly brown. Dark brown spots on top of head, primary flight feathers and mi

Native species distribution: China, Japan, Korea, Korea, Russia, Vietnam.
In China, it is mainly distributed in the eastern coastal areas (breeding grounds) such as Panjin in the south of Liaoning Province, Hebei Province, Bohai Bay in Shandong Province and Dongtai coast in Jiangsu Province, wintering in the lower reaches of the Yangtze River, Fujian, Guangdong, Hong Kong, Macao, Taiwan and Hainan Island, and passing through Jilin Province during migration.
It mainly inhabits coastal beaches, swamps and estuaries.

Black-billed gull Saunders' s Gull, medium water bird, no subspecies.

It is said that during the late Tang Dynasty, the famous poet Li Shangyin kept five kinds of rare birds in his garden, one of which was a black-billed gull with a black head and beak and a prominent white semicircle behind its eyes. But despite hundreds of accounts, drawings and poems from the 18th century to the present day that suggest the gulls were frequent in China, ornithologists who have searched for signs of the birds in and around Li's hometown have repeatedly come back disappointed and empty-handed.

In the winter of 1871, a European explorer named Robert Svenhoe claimed to have seen the bird and its nest in the coastal area of Xiamen, and named it Saunter's gull. Thirteen years later, a French explorer claimed to have seen it twice near Lake Baikal in Russia. Unfortunately, for more than a century after that, the black-billed GLS managed to evade the eager search of ornithologists and explorers around the world, and no one knew the birds' habitat, habits, and breeding laws.

Things finally changed in the spring of 1988, when Shi Zerong, who had been studying waterbirds in the coastal marshes of Yancheng, Jiangsu Province, brought back specimens of black-billed gulls with their eggs and nests. His discovery is undoubtedly one of the most important in the history of 20th century ornithology. Following Shi's breakthrough, on May 22, 1989, Liang Yu, a worker at the Binhai Beach of Shuangtaihekou Nature Reserve in Xinglongtai District, Panjin City, Liaoning Province, China, found two nests and four eggs of black-headed gulls. The news caused a huge response in the world ornithological research community. Soon, a team of Chinese and foreign ornithologists entered the Shuangtai Estuary Nature Reserve to determine whether it was a breeding ground for the mysterious black-billed gull. The survey results show that there are about 1,200 adult black-billed gulls and more than 310 nests in the Shuangtai Hekou Nature Reserve, accounting for about 70 percent of the world's estimated total. The centuries-long search for the black-billed gull's breeding grounds is over, and the dream has come true.

Black-billed gulls often live in small groups, mostly in the open sea salt land and marshland, especially the growth of short salt and alkali plants in the mud beach. It also frequently flies over nearby waters and is sometimes seen in inland lakes. Flying very light and tern like. Mix with other gulls. Right up against the tide line. The method of feeding is to make a sudden vertical descent in flight, turn around when landing and then prey on crabs and other worms. If you make a mistake and quickly fly into the air. Almost never swims.

The call of the black-billed Gull: a sharp eek-eek call.

Black-billed gull belongs to both summer and winter migratory birds. It moves to the breeding ground in the east coast of China in spring from March to April, and leaves the breeding ground in autumn from September to October.

Black-billed gulls feed mainly on aquatic invertebrates such as insects, insect larvae, crustaceans, and worms.

The breeding season of black-billed gull is from May to June. They often nest together in small groups, usually in the open coastal flat area, especially the growth of low saline-alkali plants such as alkalipus, roe grass, blood herb, and not affected by the tide on the anhydrous saline-alkali land or the mud beach in the estuary, and also in the edge of the intertidal zone or the high embankment of the intertidal zone that is less affected by the tide. The nest is usually placed on the ground or on a mound raised above the surrounding ground. The nest is disc-shaped. It is mainly composed of saline-alkali plants, such as stem and leaf of Camphor, swertia grass and wormwood. The size of the nest is 18~23 cm outside diameter, 11~12 cm inside diameter, and 1.4~4 cm deep.

Each clutch lays 1 to 3 eggs, mostly 3, a few 1 and 2, and occasionally up to 6 eggs. The eggs are pear-shaped, sandy yellow and green, with dark brown spots and spots, the size of the eggs is 48.2-52.7 mm ×35.0~38.1 mm, with an average of 50.4 mm ×36.1 mm, and the weight is 21-37 grams, with an average of 32.6 grams.

The black-billed gulls have a narrow distribution area and are few in number. According to a June 1993 survey along the coast of the Bohai Sea, the breeding population was about 634 individuals. According to the 1990 Winter Survey of Wetland Birds in Asia organized by the International Waterfowl Research Bureau, 1559 were seen in China (including 92 in Hong Kong and 27 in Taiwan), 27 in Japan, and 24 in Korea (IWRB 1990). According to Birdlife International's 2011 survey data, there are about 14,400 adult birds in the world, with a total population of about 21,000 to 22,000 birds.

Listed in Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (CMS).

Listed in the International Committee for the Conservation of Birds (ICBP) Red Book of the World's Endangered birds.

Listed on The IUCN Red List: Vulnerable Species (VU), 2012 assessment.

It was included in the List of Beneficial Terrestrial Wildlife under State Protection or of Important economic and scientific research Value issued by the State Forestry Administration of China on August 1, 2000.

Listed in China's "National Key Protected Wildlife List" (February 5, 2021).

Protect wild animals and eliminate wild meat.

Maintaining ecological balance is everyone's responsibility!