Black robin
Black robin | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Infraorder: | Passerides
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Family: | Petroicidae |
Genus: | Petroica |
Species: | P. traversi
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Binomial name | |
Petroica traversi (Buller, 1872)
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Synonyms | |
Miro traversi |
The black robin or Chatham Island robin (
Discovery and taxonomy
The first mention of the black robin in science was at a presentation given by William Travers at the Wellington Philosophical Society in 1871. He presented the findings of his son, Henry Travers, who had visited the Chatham Islands to investigate their fauna. Although Henry Travers' notes on his visit were published the following year, it was the publication of Walter Buller a month later that is considered the species' official description.[3]
In 1905 it was believed to be completely vanished: "...the so-called black Tit or black Robin, Miro traversi, have fallen victims to man and his satellites." [4]
Description
The black robin is a small, sparrow-sized bird measuring 10–15 centimetres (3.9–5.9 in). Its plumage is almost entirely brownish-black, with a black bill and brownish-black yellow-soled feet.[2]
Females are usually slightly smaller than males. Male songs are a simple phrase of 5 to 7 notes. Its call is a high-pitched single note. Their eyes are dark brown. Black robins moult between December and March.
Habitat
Black robins live in low-altitude scrub forest remnants. They are entirely
Ecology and behaviour
Black robins are territorial. Males will patrol and defend their areas. Females have been known to chase away other females. They make short flights from branch to branch and do not fly long distances.
Diet and feeding
Black robins forage in the leaf litter on the ground for grubs, cockroaches, wētā, and worms. Black robins will hunt for food during the day and night and have good night vision.
Breeding
Black robins will generally start to breed at two years of age. The female robin will make the nest, and while she lays and incubates the eggs, the male will feed the female for a rest.
Eggs are laid between early October and late December. A second clutch may be laid if the first is unsuccessful. The clutch size varies from one to three eggs, but two is typical. Eggs are creamy in colour with purple splotches. When the eggs are laid, the female will sit on them to keep them warm until they hatch, after about 18 days. Then both parents will help to feed the chicks. Young robins stay in the nest for about 23 days after hatching, but even after leaving the nest the parents will continue to feed them until they are about 65 days old. This period of parental care is longer than would normally be expected for a bird of this size. After leaving the nest, chicks often spend the first day or two on the ground learning to use their wings, and here they are exposed to predators.
Life expectancy
Survivorship between 1980 and 1991 indicates a mean life expectancy of four years. "
Conservation and distribution
There are now around 300 black robins (in 2021),[5] but in 1980 only five survived on Little Mangere Island. They were saved from extinction by Don Merton and his Wildlife Service team, and by "Old Blue", the last remaining fertile female. The remaining birds were moved to Mangere Island. The team increased the annual output of Old Blue (and later other females) by removing the first clutch every year and placing the eggs in the nest of the Chatham race of the tomtit, a technique known as cross-fostering. The tomtits raised the first brood, and the black robins, having lost their eggs, relaid and raised another brood.[6]
Many females laid eggs on the rims of nests where the eggs could not survive without help. Human conservationists pushed the eggs back into the nests where they were incubated and hatched successfully. The
All of the surviving black robins are descended from "Old Blue", giving little genetic variation among the population and creating the most extreme
Nest predation by introduced common starlings is the most common cause of nesting failure for black robins on Rangatira Island, with almost 21% of nests failing due to starlings. Incidents of failure caused by starlings are more common when black robins nest in cavities compared to open nests.[12]
The species is still
References
- ^ BirdLife International (2022). "Petroica traversi". IUCN Red List of Threatened Species. 2022: e.T22704831A209015125. Retrieved 26 July 2022.
- ^ a b Falla, R.A.,Sibson, R.B. and Turbott, E.G., illustrated by Elaine Power. (1979) The new guide to the birds of New Zealand and outlying islands. Collins, Auckland.[page needed]
- ^ Butler (1992) p. 5
- ^ https://www.biodiversitylibrary.org/item/106225#page/215/mode/1up
- ^ a b "Karure / Kakaruia / Chatham Island black robin". Retrieved 12 October 2022.
- ISBN 978-0-340-35826-9.
- PMID 24348992.
- PMID 24303793.
- S2CID 5345865.
- .
- JSTOR 1308256.
- .
Cited text
- Butler, David; Merton, Don (1992). The Black Robin: Saving the World's Most Endangered Bird. Oxford: Oxford University Press. ISBN 0-19-558260-8.
Further references
Attenborough, D. 1998. The Life of Birds. BBC
External links
- Black robin
- BirdLife Species Factsheet
- "Black robin recovery plan 2001-2011" (PDF). Department of Conservation, Wellington, New Zealand. 2001. Retrieved 2007-09-19.