Chatham oystercatchers
| Chatham oystercatchers | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Haematopus chathamensis | ||||||||||
| Hartert , 1927 |
The Chatham oystercatcher ( Haematopus chathamensis ) is a rare wader belonging to the oystercatcher genus . It is endemic to the Chatham Islands .
features
The Chatham oystercatcher reaches a size of 48 centimeters. The head, neck, top and upper chest are black. The underside is white with a faded border on the underbust. The long, thick beak is red. The short, thick legs are pink. An orange-colored eye ring runs around the iris.
Way of life
The Chatham oystercatcher builds its nest in shavings on sandy and rocky coasts, away from the water line. Occasionally it breeds in low vegetation or outside the vegetation. The breeding season extends from October to March. The clutch consists of two to three eggs. The female breeds for the first time at the age of three. The average breeding success is 0.44 fledglings per season and pair. Outside of the breeding season, the oystercatchers appear rather individually. The mean life expectancy is 7.7 years. The oldest known Chatham oystercatcher lived to be 28 years old. Its main diet consists of mussels , limpets , worms and other invertebrates.
Existence and endangerment
The Chatham oystercatcher is classified by the IUCN in the “endangered” category. After a low of 50 in 1973, the population ranged from 100 to 110 between 1987 and 1988. Of the 44 breeding pairs, 8 were found on Rangatira, where the population has continuously declined since the 1970s, 25 on Chatham , 9 on Pitt Island and 2 on Mangere Island. A census in 1998 showed 140 to 150 copies. A 2004 survey found a minimum of 266 birds along the coasts of four Chatham Islands, representing an estimated total population of 310 to 325 individuals.
Introduced predators, cows and sheep are the main threats to the Chatham oystercatcher on Pitt and Chatham. Rangatira and Mangere are free from predators, but the population here is still considered to be highly volatile. The reason for the decline on Rangatira was unknown for a long time until video cameras installed on the nests revealed feral cats as the main cause of danger. Also Wekarallen represent a potential threat.
To protect the oystercatchers from flooding, the nests were slowly moved towards the beach. Incubation in the incubator was tried, but did not increase the breeding productivity. The cattle were fenced in and signs were put up to reduce disturbance from people and dogs on the beaches. Intensive control of predators combined with nest manipulation has recently led to an increase in the population of young oystercatchers.
literature
- Warren B. King on the behalf of the International council for bird preservation (ICBP) and the Survival service commission of IUCN (1978-1979): Red Data Book 2: Aves (2nd edition). IUCN, Morges, Switzerland, 1981. ISBN 0-87474-583-7
- Josep del Hoyo et al .: Handbook of the Birds of the World. Volume 3: Hoatzins to Auks. Lynx Edicions, 1996, ISBN 84-87334-20-2 .
- Frances A. Schmechel & Shaun O'Connor: Distribution and abundance of the Chatham Island Oystercatcher (Haematopus chathamensis). Ecology & Entomology Group, PO Box 84, Lincoln University, Canterbury, New Zealand. PDF, online
- Frances A. Schmechel & Adrian M. Paterson: Habitat selection and breeding ecology of the endangered Chatham Island oystercatcher (Haematopus chathamensis) PDF, online
- Chatham Island Oystercatcher Recovery Plan 2001-2011 PDF, online
- Ernst Hartert: Types of Birds in the Tring Museum In: Novitates Zoologicae XXXIV (1927). First scientific description (as Haematopus ostralegus chathamensis ) online
Individual evidence
- ↑ Haematopus chathamensis in the IUCN Red List of Threatened Species . Retrieved November 14, 2007.