Pterodroma longirostris 

Scope: Global

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pterodroma longirostris
Species Authority: (Stejneger, 1893)
Common Name(s):
English Stejneger's Petrel
Spanish Petrel de Más Afuera
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Identification information: 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.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Hodum, P. & Torres-Mura, J.
Facilitator/Compiler(s): Bird, J., Calvert, R., Clay, R., Frere, E., Lascelles, B.
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.

Previously published Red List assessments:

Geographic Range [top]

Range Description: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).

Countries occurrence:
Chile; French Polynesia; Guam; Japan; Marshall Islands; Micronesia, Federated States of ; Northern Mariana Islands; United States; United States Minor Outlying Islands
New Zealand
Present - origin uncertain:
Additional data:
Estimated area of occupancy (AOO) - km2:13Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:47500000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:1Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):600
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: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.

Current Population Trend:Stable
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:1Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:Yes
No. of individuals in largest subpopulation:100

Habitat and Ecology [top]

Habitat and 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).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):15.6
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): Predation by feral cats, introduced brown rats Rattus norvegicus (Jones et al. 2008) and house mice Mus musculus 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 [top]

Conservation Actions: 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.

Citation: BirdLife International. 2012. Pterodroma longirostris. The IUCN Red List of Threatened Species 2012: e.T22697997A40177696. . Downloaded on 06 December 2016.
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