Pseudobulweria aterrima 

Scope: Global

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pseudobulweria aterrima
Species Authority: (Bonaparte, 1857)
Common Name(s):
English Mascarene Petrel, Réunion Petrel
French Pétrel de Bourbon
Procellaria aterrima Bonaparte, 1857
Pterodroma aterrima ssp. aterrima (Bonaparte, 1857) [in Dowsett and Forbes-Watson (1993)]
Pterodroma aterrima ssp. aterrima (Bonaparte, 1857) [in Collar et al. (1994)]
Pterodroma aterrima ssp. aterrima (Bonaparte, 1857) [in Collar and Andrew (1988)]
Pterodroma aterrima ssp. aterrima (Bonaparte, 1857) [in Sibley and Monroe (1990, 1993)]
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: 36 cm. Medium-sized, dark gadfly petrel. Dark chocolate-brown with slightly paler chin, upper throat and underwing. Black bill. Pink tarsi. Black feet, webs with pale patch towards base of inner web. Similar spp. Like Bulwer's Petrel Bulweria bulwerii and Jouanin's Petrel B. fallax but more robust, smaller with heavier bill, shorter tail and lacking wing-bar. Dark phase of Trindade Petrel Pterodroma arminjoniana has longer wings. Great-winged Petrel Pterodroma macroptera has a larger wingspan with a longer, more pointed 'hand' it is stockier in appearance with a large, rounder head and broader rear (Shirihai et al. 2014).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered C2a(ii) ver 3.1
Year Published: 2015
Date Assessed: 2015-10-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A.
Contributor(s): Bretagnolle, V., Le Corre, M. & Riethmuller, M.
Facilitator/Compiler(s): Anderson, O., Bird, J., Butchart, S., Ekstrom, J., Lascelles, B., Stattersfield, A., Symes, A., Martin, R & Ashpole, J
This species is classified as Critically Endangered because it is assumed to have an extremely small breeding population and to be undergoing a continuing decline owing to predation and light-induced mortality. Effective conservation measures are urgently needed.

Previously published Red List assessments:

Geographic Range [top]

Range Description:The species is known from Réunion (to France), by subfossil remains on Rodrigues (Mauritius) and in 2002 a single roadkill specimen in Black Gorges National Park, Mauritius (Tatayah et al. 2011). The few records include four specimens collected in the 19th century, two birds found dead in the 1970s, and rare observations of birds in the waters south of Réunion since 1964. Recently, four more individuals, two of which died, were found attracted to urban lights of Réunion towns (Le Corre et al. 2002). Five breeding sites are known (9-10 pairs in total, including one loose colony with four pairs), all restricted to a small area which is unlikely to harbour more than c. 40 breeding burrows in total (V. Bretagnolle in litt. 1999, V. Bretagnolle in litt. 2005). Calls have been heard during the breeding season (austral summer) on cliffs at 1,000 m and fledglings have been caught in March (Tatayah et al. 2011). It is possible that they nest in montane parts of the Black River Gorges, as the habitat is similar to that of their suspected nesting areas on Réunion (Tatayah et al. 2011). Data collected at sea during the period 1978-1995 suggested a population of c.1,000 individuals (Attie et al. 1997) with perhaps 45-400 pairs (Brooke 2004), although below 100 pairs is probably more likely (V. Bretagnolle in litt. 1999) and may only be a few dozen pairs (Tatayah et al. 2011). A recent survey of the known breeding area on Réunion found ten fledglings, indicating that the species continues to breed successfully on the island (M. Riethmuller in litt. 2011).

Countries occurrence:
Regionally extinct:
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) - km2:74500
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:4Continuing 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:From their at-sea counts, Attie et al. (1997) suggest that the population may be around 1,000 individuals, implying 250 (45-400) breeding pairs, although 50-100 pairs was considered more likely (V. Bretagnolle in litt. 1999), i.e. 100-200 mature individuals. However, recent estimates indicate that the breeding population may be just a few dozen pairs.

Trend Justification:  Suspected to be declining owing to predation and light-induced mortality.

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:100-200Continuing decline of mature individuals:Yes
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:All known breeding sites are on cliffs, presumably in heathy vegetation. Recent information confirms austral summer breeding, with incubation around December, and fledging between February and March (V. Bretagnolle in litt. 1999).They are thought to return to nest sites nocturnally to reduce chances of predation (Tatayah et al. 2011). The species feeds at the surface (Shirihai et al. 2014).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):17.7
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): Like the threatened Barau's Petrel Pterodroma baraui (also endemic to Réunion), the main threats are likely to be predation by feral cats and rats (V. Bretagnolle in litt. 1999), the Lesser Indian Mongoose Herpestes javanicus (Tatayah et al. 2011) and urban light-induced mortality which mainly affects inexperienced juveniles. Thirty birds have been found stranded apparently after being attracted by light between 1996 and 2011; 28 were released successfully and two died (Le Corre 1999, Le Corre et al. 1999, M. Le Corre in litt. 1999, Le Corre et al 2003, M. Riethmuller in litt. 2011). Widespread light pollution such as street lamps and sport installations are responsible for the greatest majority of light-induced petrel mortality on Réunion (Le Corre et al. 2002, Le Corre et al. 2003); the roadkill specimen on Mauritius is further evidence of the problem (Tatayah et al. 2011). Light-induced mortality of the juveniles of this rare petrel is likely to affect the long-term population dynamics but their longevity will cause a lag before real population declines are identified (Le Corre et al. 2002). The feeding behaviour of the species makes it vulnerable to fishing activities (Shirihai et al. 2014). Pesticide residues may also pose a threat (Carboneras et al. 2014).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Since 1996, there has been a campaign to quantify urban light-induced mortality and to rescue as many birds as possible (Le Corre 1999, Le Corre et al. 1999, Le Corre et al. 2002). The rescues have been successful, with over 90% of the petrels (of various species) found on Réunion being released again (Le Corre et al. 2002). From 1996-2002, a public appeal aimed at rescuing downed birds produced eight petrels, of which seven were banded and released (Le Corre et al. 2003). One ringed individual Mascarene Petrel released after being rescued has been resighted alive several years later (M. Riethmuller in litt. 2011). La Société d'Études Ornithologiques de la Réunion is working in partnership with EDF Réunion to reduce light pollution on Réunion (Bizien 2013). Surveys have identified the location and charateristics of the breeding area, however, no concerted attempts have been made to assess the impact of introduced predators and predator control has not been trialled (V. Bretagnolle in litt. 2005, M. Reithmuller in litt. 2011). A series of expeditions to remove rats from around one of the last breeding colonies of this species on Réunion was launched in August and September 2014 (Jan and Fouillot 2014). Cat control measures have also been introduced around colonies. A LIFE-funded project from 2014 to 2020 aims to limit the decline of Mascarene and Barau's Petrels through techniques including: the development of appropriate conservation actions, predator control in remote areas, awareness-raising, and improving ecological knowledge of these species (Hoarau 2014).

Conservation Actions Proposed
Develop an action plan for known breeding sites, and execute predator trapping, legal protection and monitoring of at least one or two burrows (V. Bretagnolle in litt. 1999). Continue rescue programme of young birds attracted by lights (M. Le Corre in litt. 1999, Le Corre et al. 2002). Investigate light-reduction programmes either through light-shielding or light-restriction during the fledgling period (Le Corre et al. 2002). Continue to search for further breeding grounds and, once found, evaluate population numbers, major threats and conservation action required (M. Le Corre in litt. 1999, Le Corre et al. 2002). Once suitable areas are free of predators, Mascarene Petrel calls should be broadcast throughout the night during the breeding season to encourage individuals to recolonise these sites (Jan and Fouillet 2014).

Citation: BirdLife International. 2015. Pseudobulweria aterrima. The IUCN Red List of Threatened Species 2015: e.T22697896A79066343. . Downloaded on 22 October 2016.
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