Pterodroma atrata

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PROCELLARIIFORMES	PROCELLARIIDAE

Scientific Name:

Pterodroma atrata

Species Authority:

Mathews, 1912

Common Name/s:

English

–

Henderson Petrel

Assessment Information [top]

Red List Category & Criteria:

Endangered B2ab(v) ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Calvert, R., Butchart, S., Bird, J.

Contributor/s:

Wragg, G., Brooke, M.

Justification:
This species qualifies as Endangered as it probably breeds at fewer than five locations (although currently only known from one) and its population is suspected to be declining as a consequence of predation by rats.

History:

2008	–	Endangered
2007	–	Endangered
2006	–	Endangered
2004	–	Endangered
2000	–	Endangered
1994	–	Not Recognized
1988	–	Not Recognized

Geographic Range [top]

Range Description:	Pterodroma atrata is known to breed only on Henderson Island, Pitcairn Islands (to UK), but may have also bred on Pitcairn Island in the past and has apparently become extirpated from Ducie, also in the Pitcairn Islands³. It is likely to breed on other islands in the region too⁷, such as the Gambier and Marquesas Islands (French Polynesia)^7,8. In 1991-1992, the breeding population on Henderson was estimated at c.16,000 breeding pairs and it was suggested that the species could be undergoing a long-term decline³.
Countries:	Native: Pitcairn; United States; United States Present - origin uncertain: French Polynesia; Kiribati
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Brooke (2004).
Population Trend:	Decreasing

Population:

Brooke (2004).

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Like P. heraldica it may feed predominantly on cephalopods, also taking fish and crustaceans⁶. On Henderson, it nests exclusively on the plateau, scattered in the dense forest, though nearer to the coast than P. heraldica^3,4. Breeding success is low, with less than 20% of eggs yielding fledglings and failure mostly occurring at the early chick stage³.
Systems:	Terrestrial; Marine

Threats [top]

Major Threat(s):	Predation by Polynesian rat Rattus exulans is believed to be the main cause of chick mortality on Henderson, although predation by crabs Coenobita spp. is also a possiblity³. If it ever bred on Pitcairn, it is likely to have been extirpated there because of predation by feral cats and introduced rats³. The species is potentially threatened by climate change because it has a geographically bounded distribution: it is restricted to an island with a maximum altitude of 33 m¹¹.

Major Threat(s):

Predation by Polynesian rat Rattus exulans is believed to be the main cause of chick mortality on Henderson, although predation by crabs Coenobita spp. is also a possiblity³. If it ever bred on Pitcairn, it is likely to have been extirpated there because of predation by feral cats and introduced rats³. The species is potentially threatened by climate change because it has a geographically bounded distribution: it is restricted to an island with a maximum altitude of 33 m¹¹.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway In 1997, feral cats were eradicated from Pitcairn, but subsequently re-introduced by residents. A programme to eradicate rats in 1997-1998¹ was unsuccessful, although petrels were observed prospecting the island during a period of no cats and low rat numbers⁹. In the same year, rats were eradicated on Oeno and Ducie to increase the chance of another population becoming established there¹. Several follow-up visits to Oeno and Ducie have not found any signs of rats⁵. Rat eradication from Henderson has been investigated and is feasible but difficult because of the island's isolation, but should still be pursued^2,10. In 1988, Henderson was designated a World Heritage Site. A rudimentary monitoring protocol was established on Henderson in 2003⁵. Another attempt to eradicate rats on Henderson will now take place subject only to funding after recent research removed the last potential obstacles¹¹. Conservation Actions Proposed Periodically resurvey the species to establish and monitor any trends. Periodically check Oeno and Ducie for rats, and ensure that further alien species are not accidentally introduced to the Pitcairn Islands. Eradicate rats from Henderson.

Conservation Actions:

Conservation Actions Underway
In 1997, feral cats were eradicated from Pitcairn, but subsequently re-introduced by residents. A programme to eradicate rats in 1997-1998¹ was unsuccessful, although petrels were observed prospecting the island during a period of no cats and low rat numbers⁹. In the same year, rats were eradicated on Oeno and Ducie to increase the chance of another population becoming established there¹. Several follow-up visits to Oeno and Ducie have not found any signs of rats⁵. Rat eradication from Henderson has been investigated and is feasible but difficult because of the island's isolation, but should still be pursued^2,10. In 1988, Henderson was designated a World Heritage Site. A rudimentary monitoring protocol was established on Henderson in 2003⁵. Another attempt to eradicate rats on Henderson will now take place subject only to funding after recent research removed the last potential obstacles¹¹.

Conservation Actions Proposed
Periodically resurvey the species to establish and monitor any trends. Periodically check Oeno and Ducie for rats, and ensure that further alien species are not accidentally introduced to the Pitcairn Islands. Eradicate rats from Henderson.

Citation:	BirdLife International 2010. Pterodroma atrata. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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