Maori gull

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Maori gull
Black-billed Gull (5) .JPG

Maori gull ( Chroicocephalus bulleri )

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Laridae
Subfamily : Seagulls (larinae)
Genre : Chroicocephalus
Type : Maori gull
Scientific name
Chroicocephalus bulleri
( Hutton , 1871)

The Maori gull ( Chroicocephalus bulleri , syn .: Larus bulleri ) is a species of gull endemic to New Zealand . It is a medium-sized seagull with white and gray plumage and characteristic markings on the wings. The beak is relatively long and slender.

The IUCN classifies the black-billed gull as endangered ( endangered ), since the stock has declined sharply over the past three decades.

Appearance

The Maori gull reaches a body length of 35 to 38 centimeters. The wing length is 27.4 to 31.0 centimeters. The wingspan is 81 to 96 centimeters. Maori gulls weigh between 109 and 299 grams, males are consistently slightly larger and heavier than females.

Adult Maori gulls have a white head, white tail, and a white underside of the body. The mantle and the wing covers are very pale gray to white-gray. The wings are white and lined with black at the end. The beak color is individually different. It ranges from solid black to black with a dull red beak base. The feet and legs are black. The iris is yellowish-white, the narrow eye ring is black.

Young birds are colored similarly to adult birds, but have pale yellowish-red-brown speckles on the wing covers. Individual juveniles also have brownish spots on the top of their heads. The beak of young birds is yellowish-brown except for the black tip of the beak. The iris is dark.

It can be confused with the red-billed gull, which is also common in New Zealand . The Maori gull differs from this species mainly in its slimmer and longer beak.

Distribution and existence

The Maori gull breeds on the rivers and lakes of New Zealand. Its main distribution area is on the South Island , but it also breeds in several places on the North Island . In winter she stays more in the coastal areas of New Zealand. During the winter months it also occasionally reaches Stewart Island and the Snare Islands .

The population is estimated by the IUCN at 96,000 sexually mature individuals.

Way of life

Maori gulls occasionally go to garbage dumps to look for food, but mostly eat insects, fish, aquatic invertebrates and earthworms. They usually feed in schools and move no further than three miles from the breeding colony while foraging. They often follow plowing tractors while foraging and can be seen regularly in freshly plowed fields.

Maori gulls are colony breeders. Couples often use the same breeding site for several years in a row. They return to their breeding colonies from mid-September. Nest building, which begins at the beginning of October, is largely synchronized. The nest consists of small branches, the nesting trough is covered with grass. The clutch usually consists of two eggs, but clutch sizes can vary between one and three eggs. The breeding season is 20 to 24 days. Both parent birds are involved in the brood. The chicks fledge after about 26 days. Maori gulls are sexually mature at two years of age, but usually do not breed until they are three to four years old.

supporting documents

literature

  • Hadoram Shirihai: A Complete Guide to Antarctic Wildlife - The Birds and Marine Mammals of the Antarctic Continent and Southern Ocean , Alula Press, Degerby 2002, ISBN 951-98947-0-5

Single receipts

  1. ↑ BirdLife Factsheet on the Maori Gull , accessed December 4, 2010
  2. ↑ Shirihai, p. 228
  3. ↑ BirdLife Factsheet on the Maori Gull , accessed December 4, 2010
  4. ^ Shirihai, p. 229

Web links

Commons : Maori gull ( Chroicocephalus bulleri )  - Collection of images, videos and audio files