Justification This species qualifies as Vulnerable owing to its very small breeding range, which renders it susceptible to stochastic events and human impacts. Confirmation that introduced predators are causing a decline may qualify it for uplisting to Critically Endangered.

Family/Sub-family Procellariidae

Species name author (Stejneger, 1893)

Taxonomic source(s) AOU checklist (1998 + supplements), Brooke (2004), SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996), Turbott (1990)

Identification 26 cm. Small, typical "M" marked gadfly petrel. Dark grey upperparts with sharp "M" mark. Bold and very dark grey cap and mask, extending to dark grey half collar on upper breast. Dark grey rump and uppertail-coverts. White throat and lower chest/belly. Predominantly white underwing, but black tip and narrow black trailing edge, extending to leading edge with slight thickening at carpal joint. Similar spp. Separated from most other small gadfly petrels by whiter underwing. Cook's Petrel P. cookii and de Filippi's Petrel P. defilippiana have paler crown and nape, and outertail feathers that are paler than central feathers. Pycroft's Petrel P. pycrofti has less extensive dark patch around eye. Juan Fernández Petrel P. externa is larger, with white on rump and small black carpal patch.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

400,000

stable

47,000,000 km²

No

Ecology: It nests in burrows on slopes in Dicksonia externa fern-forest and adjacent grasslands at elevations of 700-1,1120 m ⁶. Breeding begins in November. One egg is laid in late November-early December with hatching in late January-mid February. Fledging occurs in May. It forms mixed-species colonies with P. externa¹, typically forming small monospecific clusters of burrows in shallow soils within the larger P. externa colony⁷. It feeds in pelagic waters primarily on squid and small fish⁷.

Threats Predation by feral cats, introduced brown rats Rattus norvegicus⁹ and house mice Mus mus has been documented⁷ and may be causing a population decline^{6, 7}. In mixed colonies with P. externa, cats prefer to take the smaller P. longirostris¹. Introduced goats (c.6,000) are destroying suitable breeding habitat^3,5. In 1995, a fire destroyed habitat within part of the colony⁶, although it is not known if the species was nesting in that part of the colony. In 2002, a massive rainstorm caused multiple landslides within the colony, although the effects of this on the species were unquanitified⁸. Decreased lobster catches near Isla Robinson Crusoe are displacing fishers to Alejandro Selkirk (where they live between September and May), resulting in an increase in human disturbance⁶, although the size of the community has apparently not increased since 2001. The species is potentially threatened by climate change because it has a geographically bounded distribution: its altitudinal distribution falls entirely within 2,000 m of the highest mountain top within its range (1,649 m)¹⁰.

Conservation measures underway The Juan Fernández Islands were designated as a national park in 1935 (protected from 1967) and a UNESCO Biosphere Reserve in 1977^5,6. The Chilean government began a habitat restoration programme in 1997⁶ which included goat control, but it concluded in 2003. The islands have been nominated for World Heritage listing³. Park rangers have been trained in fighting fires, but there is only one ranger on Alejandro Selkirk⁶. Sheep were removed from Alejandro Selkirk in 1983¹.

Conservation measures proposed Maintain and expand population monitoring plots⁷. Determine contemporary breeding population size. Eradicate introduced fauna (feral cats, rats, mice and goats) from Alejandro Selkirk.

References 1. Carboneras (1992d). 2. Falla (1962). 3. Hulm (1995). 4. Roberson and Bailey (1991). 5. Stattersfield et al. (1998). 6. J. C. Torres-Mura in litt. (1999). 7. Hodum and Wainstein (2003, 2004). 8. Hodum in litt. (2006). 9. Jones et al. (2008). 10. Birdlife International (unpublished data).

Text account compilers Jeremy Bird (BirdLife International), Rob Calvert (BirdLife International), Rob P Clay (BirdLife International), Esteban Frere (BirdLife International), Ben Lascelles (BirdLife International)

Contributors Peter Hodum (Oikonos), J. C. Torres-Mura

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International)

Recommended citation BirdLife International (2010) Species factsheet: Pterodroma longirostris. Downloaded from http://www.birdlife.org on 30/7/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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