Red-billed gull
| Red-billed gull | ||||||||||||
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Red-billed gulls. On the far left a young gull in the second winter, next to it a young gull in the first winter and then an adult bird. |
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| Scientific name | ||||||||||||
| Chroicocephalus scopulinus | ||||||||||||
| ( JR Forster , 1844) |
The red-billed gull ( Chroicocephalus scopulinus , Syn . : Larus scopulinus ) is a monotypical species of gull that is endemic to New Zealand . It is a medium-sized, gray and white drawn seagull with a characteristic drawing on the wing tips. The beak is relatively short and strong. The wings are wide with rounded ends. The type has a very close resemblance to the to the Australian fauna belonging Silver Gull on. However, the range of the two species only overlaps in waters around Tasmania.
Appearance
The red-billed gull reaches a body length of 37 centimeters. The wing length is 26.3 to 28.9 centimeters and the wingspan is 91 to 96 centimeters. The weight is 245 to 360 grams. Females tend to be slightly smaller than males and have a smaller beak.
Adult red-billed gulls have a white head, a white tail, and a white underside of the body. The mantle and the wing covers are light gray. The wings are predominantly black with white tips and a white, diagonal markings on the middle wings. The beak and legs are bright red. The eyes are yellowish white with a narrow red eye ring.
Young birds in the first year are very similar to the adult birds, but have a noticeable brownish markings on the wings. Older fledglings increasingly resemble adult birds. The eyes, however, are significantly darker.
Distribution and existence
The distribution area of the red-billed gull includes the coasts and lakes of New Zealand. It is also found on islands around New Zealand. These include the Snares Islands , Chatham Islands , Auckland Islands and Campbell Island with its small surrounding islands. The population is estimated at around 500,000 pairs.
Way of life
During the breeding season, red-billed gulls mainly live on krill and other crustaceans , earthworms, insects and small fish. Outside the breeding season, they eat a wider range of fish and also visit rubbish tips. They regularly steal food from other seabirds and waders, and occasionally eat berries as well.
Red-billed gulls form long-term mating and usually return to their native colony. The breeding season begins in early July. The eggs are usually laid between September and December. Red-billed gulls occasionally breed in densely packed colonies, but also regularly on their own. The clutch usually consists of two eggs, the clutch size varies between one and five eggs. The clutch is incubated for 22 to 26 days. The chicks can fledge after 28 to 35 days.
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 (English).
Web links
- Larus scopulinus. International Union for Conservation of Nature and Natural Resources , May 1, 2012, archived from the original January 1, 2014 ; accessed on May 4, 2018 (English, original website no longer available).