|Scientific Name:||Pterodroma ultima|
|Species Authority:||Murphy, 1949|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
|Contributor/s:||Bretagnolle, V. & Thibault, J.|
This species qualifies as Near Threatened because although rats have been eradicated at the largest breeding population, the population continues to slowly decline within its moderately small range.
|Range Description:||Pterodroma ultima breeds in the Pitcairn Islands (to UK), the Tuamotu Archipelago, the Austral Islands (Garnett 1984) and the Gambier Islands (French Polynesia) (Thibault and Bretagnolle 1999) and perhaps in the Cook Islands. In the Pitcairns, an estimated 2,500 (± 500) breed on Henderson, 12,500 (± 2,500) on Oeno, and 250,000 (± 29,000) on Ducie (Brooke 1995a). In the Tuamotus, colonies occur on Mururoa and Fangataufa (Holyoak and Thibault 1984), although these may have disappeared owing to nuclear tests and the recent construction of an airstrip (V. Bretagnolle in litt. 1999, J.-C. Thibault in litt. 2000). In the Australs, it breeds only on a limited number of islets off Rapa where the population was estimated at 10-100 pairs in 1990 (Thibault and Varney 1991). In the Gambiers, proof of breeding was found for the first time on Manui and numbers were estimated at 5-10 pairs (Thibault and Bretagnolle 1999). In the Cook Islands, a specimen was collected probably from Rarotonga or perhaps one of the other southern Cook Islands, between c.1899 and 1904 (Gill 1996). In 2009, 2 pairs were reported nesting on Easter Island (M. Martin in litt. 2011). Non-breeding dispersal is poorly known but mostly north as far as north-west Hawaiian chain in west, yet frequently seen in eastern tropical Pacific as far as Californian current.|
Native:French Polynesia; Pitcairn
Vagrant:Saint Helena, Ascension and Tristan da Cunha
Present - origin uncertain:American Samoa (American Samoa); Canada; Chile; Cook Islands; Costa Rica; Ecuador; French Southern Territories (the); Kiribati; Mexico; Niue; Peru; Samoa; Tokelau; Tonga; United States; United States Minor Outlying Islands
|Range Map:||Click here to open the map viewer and explore range.|
|Habitat and Ecology:||Has been recorded nesting in rocky cliffs during March. On Henderson Island, has been recorded nesting in woodland behind beaches or in low fern scrub close to the island’s cliffs. Nesting is seasonal, with egg-laying between late May and early July. 50-day incubation period is completed in three stints. The male takes the first stint, averaging 19.3 days, following a similar stint by the female, and then the male for the second time. Egg-hatching normally occurs towards the end of the male’s second stint (Brooke 2010). Off-duty birds calculated as having a foraging radius of 4,600 km, potentially accessing highly productive Antarctic Polar Front, 6,500 km to the south (Brooke 2010). Even rich waters off California, 6,500 km to north, could be reached if the birds flew for more than 12 hours a day and birds are seen most often in those waters during the incubation months of June and July (Brooke 2010). Breeding sites are completed abandoned during the non-breeding period, after November (Anon. 2007). They feed mainly at sea on cephalopods, fish and small crustacea (Anon. 2007).|
|Major Threat(s):||Pacific rat Rattus exulans is present on some islands, and causes low breeding success on Henderson in particular, less than 5% (Brooke 1995a, 2010). The Henderson population could be sustained through immigration from other colonies but there is no evidence that this occurs (Brooke 2010). The species is potentially threatened by climate change because it has a geographically bounded distribution: it is restricted to an island or islands with a maximum altitude of 33 m (BirdLife International unpublished data). There is no information on trends.|
Conservation Actions Underway
Although the species breeds at a small number of locations and may be declining at some of these, the recent eradication of rats on Ducie (Bell and Bell 1998) secures the largest population. Following a feasibility study (Brooke and Towns 2008) a rat eradication operation was carried out on Henderson Island in August 2011 (J. Hall in litt. 2012). A follow-up monitoring expedition is planned for 2013 to assess the success of the rat eradication.
Conservation Actions Proposed
Monitor the Ducie population. Continue searches for the species in the Tuamotus (V. Bretagnolle in litt. 1999). Continue the programme of Pacific rat eradication on Henderson.
|Citation:||BirdLife International 2012. Pterodroma ultima. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.|
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