Pterodroma defilippiana 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pterodroma defilippiana (Giglioli & Salvadori, 1869)
Common Name(s):
English Masatierra Petrel, Defilippe's Petrel, Defilippi's Petrel, Masatierra Petrel, Mas Atierra Petrel
Spanish Fardela blanca de Más a Tierra, Petrel chileno
Taxonomic Source(s): Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
Identification information: 26 cm. Small, typical "M" marked gadfly petrel. Dark grey upperparts with sharp "M" mark. White forehead but dark grey cap and mask, extending to grey half-collar on upper breast. Dark grey rump and uppertail-coverts. Paler outer tail feathers. White throat and lower chest/belly. Predominantly white underwing, but black tip and narrow trailing edge, extending to leading edge. Similar spp. Separated from most other small gadfly petrels by whiter underwing. Cook's Petrel P. cookii has shorter and thinner bill and shorter tail. Stejneger's Petrel P. longirostris has paler crown and nape, and lacks darker central tail feathers. Pycroft's Petrel P. pycrofti is possibly inseparable, but ranges may not overlap.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Hodum, P. & Torres-Mura, J.
Facilitator/Compiler(s): Bird, J., Clay, R.P., Moreno, R., Temple, H.
This species qualifies as Vulnerable because it has a very small breeding range at three or four locations, and is therefore susceptible to stochastic events or human impacts. It is likely to have been extirpated from one island some time ago, but the bulk of the population is presumably stable.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Pterodroma defilippiana is an east Pacific seabird, currently breeding on three or four islands off the coast of Chile. In the Desventuradas Islands, 10,000 or more birds occurred on San Ambrosio in 1970, with an additional 150-200 pairs on San Félix. The most recent estimate is 4600 breeding individuals on San Ambrosio (Hodum 2012). In the Juan Fernández Islands, it has possibly been extirpated on Robinson Crusoe, and the population on Santa Clara was suggested at hundreds, possibly thousands, in 1986, but available habitat was found for only 100-200 individuals in 1991. A recent estimate for the Juan Fernández Islands was 954 breeding individuals, of which 327 breeding pairs are on Santa Clara (Hodum 2012).  The remaining breeding birds are on small rock stacks immediately offshore of Robinson Crusoe.
It ranges at sea in the nearby Peru Current, south of the equator (Roberson and Bailey 1991, Spear et al. 1992).

Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:9Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:1900000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:3Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The world population may be no greater than 10,000 individuals. The estimate of global breeding population, based on on-the-ground counts of nests, is 2777 breeding pairs (or 5554 breeding individuals) (Hodum 2012).

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:
Number of mature individuals:5554Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:3Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:

It breeds on sheltered cliff-ledges, crevices, caverns and amongst boulders at the foot of lava cliffs. It nests colonially, with eggs apparently laid late July-early August, chicks hatching in September-early October and colonies abandoned in December (Hodum 2012). However, it has been reported breeding in February on San Félix. 

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): Feral cats, rats, house mice and coatis are blamed for the possible extinction on Robinson Crusoe (Hodum 2012), and cats have caused extensive mortality on San Félix. Rats have been cited as a predator but on which island is unknown. Santa Clara and San Ambrosio appear to be predator-free, nevertheless there are feral goats on San Ambrosio and their effects on the species have not been assessed.

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 Biosphere Reserve in 1977. The Chilean government began a habitat restoration programme in 1997 (J. C. Torres-Mura in litt. 1999), and the islands have been nominated for World Heritage listing (Hulm 1995). Mapping of breeding colonies and a population estimate for all breeding locations except for San Félix were completed in 2010-2012 by Oikonos Ecosystem Knowledge. A long-term breeding season monitoring program was established on Santa Clara in 2010 by Oikonos. Monitoring on San Ambrosio is being planned by Oikonos for the 2016 breeding season, in collaboration with local fishermen. Oikonos has also undertaken awareness-building programs with the local community in Juan Fernández.

Conservation Actions Proposed

Remove all introduced mammals, initially within intensively managed, fenced, feasibility study areas. 

Citation: BirdLife International. 2016. Pterodroma defilippiana. The IUCN Red List of Threatened Species 2016: e.T22697990A93652447. . Downloaded on 19 January 2018.
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