Pterodroma cookii

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 cookii

Species Authority:

(Gray, 1843)

Common Name/s:

English

–

Cook's Petrel

Assessment Information [top]

Red List Category & Criteria:

Vulnerable A2e;D2 ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

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

Contributor/s:

Merton, D., Rayner, M., Taylor, G., Tennyson, A.

Justification:
This species has been listed as Vulnerable because although there have been rapid declines in the past, the improving status of the population and habitat, in particular following the successful eradication of the last introduced predators (Pacific rat) on Little Barrier Island (where by far the largest numbers breed), leading to an increase in fledging success from 5% to 70%. This key step in turning the fortunes of the species followed the earlier eradication of cats from Little Barrier Island in 1980, and Weka from Codfish Island in the early 1980s. Although tiny numbers still occur on Great Barrier Island it may have been effectively extinct as a reproductively viable population for several decades.

History:

2009	–	Vulnerable
2008	–	Endangered
2007	–	Endangered
2006	–	Endangered
2004	–	Endangered
2000	–	Endangered
1996	–	Vulnerable
1994	–	Vulnerable

Geographic Range [top]

Range Description:	Pterodroma cookii is endemic to New Zealand, where it breeds on Little Barrier, Great Barrier and Codfish Islands. On Great Barrier, only 12 burrows have been found during the last 25 years; there may be fewer than 20 pairs⁶ and it is extinct as a reproductively viable population. On Codfish the population declined from c.20,000 pairs in the early 1900s almost to extinction before predators were removed in 1982; it is now increasing and was estimated at 5,000 breeding pairs in 2007^1,2,6,9. The population on Little Barrier is also likely to be increasing^2,4, and modelling and spatial analysis has suggested that as many as 286,000 pairs may breed on Little Barrier Island annually⁸. Birds migrate to the east Pacific Ocean, mainly between 34°S and 30°N¹.
Countries:	Native: American Samoa; Chile; Cook Islands; French Polynesia; Mexico; New Zealand; Niue; Norfolk Island; Peru; Pitcairn; United States; United States; United States; United States; United States; United States; United States; United States Minor Outlying Islands; Wallis and Futuna Vagrant: Australia; Kiribati Present - origin uncertain: Ecuador; French Southern Territories (the); New Caledonia; Samoa; Tokelau; Tonga; Tuvalu
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Rayner et al (2007) based on burrow surveys extrapolated through GIS.
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It breeds in burrows on forested ridges and steep slopes between 300-700 m on Little Barrier and 4-350 m on Codfish; ideal breeding habitat is unmodified forest close to ridgetops with a low and open canopy and many large stems^2,7. It formerly bred in suitable habitat throughout New Zealand⁶. It feeds mainly on squid, crustaceans and small fish¹.
Systems:	Terrestrial; Marine

Threats [top]

Major Threat(s):	On Little Barrier, introduced cats were a major predator of chicks and adults. Although cats were eradicated, the number of petrel burrows with chicks declined from 32% when both cats and rats were present to just 9% following cat eradication because the population of Rattus exulans (also a predator of petrel chicks) increased dramatically^1,4,5,7. On Great Barrier, the population is severely threatened by cats, black rat R. rattus and Pacific rat R. exulans. On Codfish, the population declined owing to severe predation by the introduced Weka Gallirallus australis².

Major Threat(s):

On Little Barrier, introduced cats were a major predator of chicks and adults. Although cats were eradicated, the number of petrel burrows with chicks declined from 32% when both cats and rats were present to just 9% following cat eradication because the population of Rattus exulans (also a predator of petrel chicks) increased dramatically^1,4,5,7. On Great Barrier, the population is severely threatened by cats, black rat R. rattus and Pacific rat R. exulans. On Codfish, the population declined owing to severe predation by the introduced Weka Gallirallus australis².

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway Cats were eradicated from Little Barrier by 1980, and G. australis was eradicated from Codfish between 1980 and 1985⁴. R. exulans was succesfully eradicated from Little Barrier Island in 2004, increasing fledging success from 5% to 70%^7,9. An eradication operation took place in August 1998 on Codfish - the outcome of which is unknown³. Conservation Actions Proposed Survey Codfish to locate new breeding burrows and colonies. Monitor breeding success and recruitment on Codfish, and map burrows at five-yearly intervals. Monitor status of population on Great Barrier: collect dead birds, tag and map active burrows, record locations of display areas. Implement appropriate pest control if a colony (more than five burrows) is found on Great Barrier. Reintroduce to mainland "islands" (areas of the mainland with intensive predator control)⁶.

Conservation Actions:

Conservation Actions Underway
Cats were eradicated from Little Barrier by 1980, and G. australis was eradicated from Codfish between 1980 and 1985⁴. R. exulans was succesfully eradicated from Little Barrier Island in 2004, increasing fledging success from 5% to 70%^7,9. An eradication operation took place in August 1998 on Codfish - the outcome of which is unknown³.

Conservation Actions Proposed
Survey Codfish to locate new breeding burrows and colonies. Monitor breeding success and recruitment on Codfish, and map burrows at five-yearly intervals. Monitor status of population on Great Barrier: collect dead birds, tag and map active burrows, record locations of display areas. Implement appropriate pest control if a colony (more than five burrows) is found on Great Barrier. Reintroduce to mainland "islands" (areas of the mainland with intensive predator control)⁶.

Citation:	BirdLife International 2010. Pterodroma cookii. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 16 May 2012.
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