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Stejneger's Petrel Pterodroma longirostris

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.

Taxonomic source(s)
Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

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.

Distribution and population
Pterodroma longirostris breeds on Alejandro Selkirk Island in the Juan Fernández Islands, Chile. The population is estimated at 131,000 pairs (Carboneras 1992d), but more recent estimates suggest that it may be lower (Hodum and Wainstein 2003, 2004) and may be declining. It is a migrant to the north-west Pacific off Japan (Roberson and Bailey 1991). Birds appear to move through a corridor south-east of Hawaii in April-June (Roberson and Bailey 1991), with some straying as far south as North Island, New Zealand (Falla 1962). There may be a clockwise movement through the north Pacific in late summer and autumn, with birds recorded off California, USA (Roberson and Bailey 1991).

Population justification
In 1986, the population was estimated at 131,000 pairs, implying a world population in excess of 400,000 individuals.

Trend justification
The population is thought to be stable although the very small breeding range of the species renders it susceptible to stochastic events, human impacts and predation by invasive species.

Ecology
It nests in burrows on slopes in Dicksonia externa fern-forest and adjacent grasslands at elevations of 700-1,1120 m (J. C. Torres-Mura in litt. 1999). 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. externa (Carboneras 1992d), typically forming small monospecific clusters of burrows in shallow soils within the larger P. externa colony (Hodum and Wainstein 2003, 2004). It feeds in pelagic waters primarily on squid and small fish (Hodum and Wainstein 2003, 2004).

Threats
Predation by feral cats, introduced brown rats Rattus norvegicus (Jones et al. 2008) and house mice Mus mus has been documented (Hodum and Wainstein 2003, 2004) and may be causing a population decline (J. C. Torres-Mura in litt. 1999, Hodum and Wainstein 2003, 2004). In mixed colonies with P. externa, cats prefer to take the smaller P. longirostris (Carboneras 1992d). Introduced goats (c.6,000) are destroying suitable breeding habitat (Hulm 1995, Stattersfield et al. 1998). In 1995, a fire destroyed habitat within part of the colony (J. C. Torres-Mura in litt. 1999), 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 unquanitified (Hodum in litt. 2006). 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 disturbance (J. C. Torres-Mura in litt. 1999), 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) (Birdlife International unpublished data).

Conservation Actions Underway
The Juan Fernández Islands were designated as a national park in 1935 (protected from 1967) and a UNESCO Biosphere Reserve in 1977, Stattersfield et al. 1998, J. C. Torres-Mura in litt. 1999). The Chilean government began a habitat restoration programme in 1997 (J. C. Torres-Mura in litt. 1999) which included goat control, but it concluded in 2003. The islands have been nominated for World Heritage listing (Hulm 1995). Park rangers have been trained in fighting fires, but there is only one ranger on Alejandro Selkirk (J. C. Torres-Mura in litt. 1999). Sheep were removed from Alejandro Selkirk in 1983 (Carboneras 1992d). Conservation Actions Proposed
Maintain and expand population monitoring plots (Hodum and Wainstein 2003, 2004). Determine contemporary breeding population size. Eradicate introduced fauna (feral cats, rats, mice and goats) from Alejandro Selkirk.

References
Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.

Carboneras, C. 1992. Procellariidae (Petrels and Shearwaters). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 216-257. Lynx Edicions, Barcelona, Spain.

Falla, R. A. 1962. New Zealand records of Pterodroma longirostris and a new record of Pterodroma leucoptera. Notornis 9(8): 275-277.

Hodum, P.; Wainstein, M. 2003. Biology and conservation of the Juan Fernadez seabirds community.

Hulm, P. 1995. Robinson Crusoe's Islands face an uncertain future. Plant Talk: 19-21.

Jones, H.P., Tershy, B.R., Zavaleta, E.S., Croll, D.A., Keitt, B.S., Finkelstein, M.E. and Howald, G.R. 2008. Severity of the effects of invasive rats on seabirds: a global review. Conservation Biology 22(1): 16-26.

Roberson, D.; Bailey, S. F. 1991. Cookilaria Petrels in the eastern Pacific Ocean. American Birds 45: 1067-1081.

Stattersfield, A. J.; Crosby, M. J.; Long, A. J.; Wege, D. C. 1998. Endemic bird areas of the world: priorities for bird conservation. BirdLife International, Cambridge, U.K.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Bird, J., Calvert, R., Clay, R., Frere, E., Lascelles, B.

Contributors
Hodum, P., Torres-Mura, J.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Pterodroma longirostris. Downloaded from http://www.birdlife.org on 30/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/08/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Stejneger’s petrel (Pterodroma longirostris) 0

Key facts
Current IUCN Red List category Vulnerable
Family Procellariidae (Petrels, Shearwaters)
Species name author (Stejneger, 1893)
Population size mature individuals
Population trend Stable
Distribution size (breeding/resident) 47,500,000 km2
Country endemic? Yes
Links to further information
- Additional Information on this species