Pterodroma baraui 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pterodroma baraui (Jouanin, 1964)
Common Name(s):
English Barau's Petrel
French Pétrel de Barau
Spanish Fardela de Barau, Petrel de Barau
Taxonomic Source(s): Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
Identification information: 38 cm. Medium-sized, grey-and-white gadfly petrel. White forehead, black cap merging to greyish-brown back and upperwing. Paler wing-tips give scaled appearance. Slightly darker tail. Moderately defined "M" mark across wings. White chin, throat and rest of underparts, except for some grey mottling on sides of breast and flanks. White underwing with dark trailing edge, dark tip, narrow black edge to leading edge distal to carpal joint. Black thickens at joint. Then clear black bar extending from joint towards centre of wing. Similar spp. Capped appearance, white underparts, and distinctive underwing separate this from any other Indian Ocean Pterodroma.

Assessment Information [top]

Red List Category & Criteria: Endangered B2ab(v) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Attié, C., Bretagnolle, V., Couzi, F.X., Gee, B., Le Corre, M., Lequette, B., Pinet, P. & Salamolard, M.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Calvert, R., Ekstrom, J., Moreno, R., Shutes, S., Stattersfield, A., Taylor, J., Temple, H.
This species may have undergone a rapid population decline owing to illegal shooting in the 1990s, but has apparently recovered. However, it has a very small range when breeding (probably at fewer than five locations) and a small population, both of which are thought to be declining. It is therefore classified as Endangered.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Pterodroma baraui nests on the Massifs of Piton des Neiges and Grand Bénare, Réunion (to France) (one nest has been discovered on Rodriguez; Van den Berg et al. 1991). Tracking research has shown that the at-sea distribution when breeding include a wide area from Reunion to 1000 km south of Madagascar and up to the coasts of South Africa (Pinet et al. 2012). After breeding, the species migrates eastward to a wide area located on both sides of the 90 East ridge (Pinet et al. 2011). At sea observations in the northern Indian Ocean suggest that some birds may disperse widely throughout the tropical Indian Ocean.

Countries occurrence:
Australia; British Indian Ocean Territory; Christmas Island; Cocos (Keeling) Islands; Indonesia; Madagascar; Mauritius; Mozambique; South Africa; Sri Lanka
Additional data:
Estimated area of occupancy (AOO) - km2:20Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:31300000
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:4Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):2200
Upper elevation limit (metres):3000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Most breeding colonies of  Barau's Petrel are completely out of reach and have never been assessed properly until recently. Thus, most previous population estimates and trends should be taken with caution. Recently, a combination of methods including annual census of fledglings attracted to lights from 1996 to 2016 (SEOR unpublished), wide scale radar survey (Gineste et al. in prep.), capture and recapture analysis at breeding colonies (unpublished), study of burrow occupancy, habitat modelling (Pinet et al. in prep.) and population genetics (Humeau et al. in prep.) have been conducted to assess the size of the population. Such an effort has provided a preliminary estimate of 15000 to 20000 breeding pairs, a larger number of mature individuals than previously reported. Nevertheless, previous estimates were based only on a partial knowledge of the species.

Trend Justification:  The species was suspected to be undergoing a long-term decline in line with increased juvenile mortality caused by disorientation resulting from light pollution. Since 1996 a wide scale rescue campaign has been conducted and more than 12000 fledglings have been rescued successfully. Using these and other data a reassessment of the population trend and of the status of the species will be provided in the near future. Both adults and chicks are also predated by introduced mammals (cats and rats) at breeding colonies.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:30000-40000Continuing 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:It nests on cliff-ledges in volcanic ash soils beneath sparse, heathy vegetation such as Philippia montana associated with upland elfin forest (Probst et al. 2000). It is a summer breeder, with most birds arriving at the colony in September; the prelaying exodus occurs in October and birds lay synchronously in November each year. Chick-rearing starts in late December to early January and fledglings leave their colony throughout April. Breeding adults forage over a wide area between Réunion, the south of Madagascar and South Africa (Pinet et al. 2012). Prebreeding and incubating birds perform very long foraging trips up to the continental plateau of South Africa and the Walter Shoal area, 1000 km south of Madagascar. When rearing their chicks, birds adopt a dual foraging strategy with a clear alternation of short (2-3 days) trips around Reunion Island and long trips (10-14 days) trips to the south of Madagascar. During the non-breeding season, it forages in regions characterized by warm sea surface temperatures and low productivity, consistent with strong and reliable easterly winds, between the western South Equatorial Current and the eastern Equatorial Counter Current (Pinet et al. 2011). Birds leave the colony in late March, reaching wintering areas in mid-April, returning to the colony 5-15 September (Pinet et al. 2011). Both sexes, and breeders and non-breeders, show similar migration schedules, with males returning to the colony slightly earlier, and mean return dates coinciding with full moon phase, suggesting that birds use this cue to synchronize their activity (Pinet et al. 2011). Mean distances travelled per day en route to wintering areas was 110-600 km; once there this dropped significantly (Pinet et al. 2011). There is considerable consistency in wintering areas year on year (Pinet et al. 2011). It feeds at the surface, taking mostly squid and fish, foraging alone or in small flocks, often associating with Sooty Terns Sterna fuscata and Tropical Shearwaters Puffinus bailloni. Diet study and stable isotope ratios suggest that young and adults consume different prey (Kojadinovic et al. 2009, Danckwert et al. 2016). Its main prey are fish and squids.

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:No
Generation Length (years):15.6
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): Introduced cats and rats are present at all colonies that have been visited. Cats predate on adults and fledglings (Faulquier et al. 2009) whereas rats predate on eggs and chicks (unpublished). It has been estimated that a single cat may kill as many as 90 adult Barau's Petrels per year. Long-lived seabirds are particularly sensitive to any additive mortality and a population modelling study has shown that such predation rate may lead to a rapid population decline (Dumont et al. 2010, Russell et al. 2009).

Juveniles are attracted by lights in urban areas, where some die of starvation or are taken by cats and dogs (Le Corre et al. 2002, Salamolard et al. 2007). Light-induced mortality of the juveniles of this rare petrel is a considerable problem, likely to affect the species long term populations dynamics. Widespread light pollution such as street lamps and sport installations are responsible for the vast majority of petrel light-induced mortality on Réunion (Le Corre et al. 2002). It has been suggested that perhaps as many as 40-60% of young birds are disorientated and ultimately suffer light-induced mortality each year (Le Corre 1999, Le Corre et al. 2002). Recent analysis of light-induced mortality suggested a more conservative estimation of 5%-20% depending of the moon phase and weather conditions. From 1996 to 2016, at least 13000 fledglings have been found grounded as a consequence of light attraction and 90% of them have been rescued successfully. 

A recent study (Cartraud 2016) has shown that the species is also subject to the global plastic pollution of the ocean as plastic debris has been found in the digestive tracts of 45% of 60 birds analysed. The impact of this pollution on the survival of the affected birds is unknown.

Finally, global warming may also affect the species in the future as a recent study based on a robust tracking dataset and state-of-the-art habitat suitability modelling has shown that the wintering habitat may shift southward and may be reduced in size during the 21st century as a consequence of global warming (Legrand et al. 2016).

Conservation Actions [top]

Conservation Actions:

Conservation Actions Underway

Since the discovery (in 1996) of the massive loss of fledglings induced by light pollution, an island scale rescue campaign has been conducted annually and has lead to the rescue of>12000 fledglings. Recent mark-recapture operations conducted at breeding colonies have shown that some of these birds are now recruiting as breeding adults, which demonstrates that rescue campaigns have a strong positive impact at the population level. A modelling study also shows that without the rescue campaign, the population would have declined at a rate of at least 1.1% per year (Le Corre et al. in prep.).

Measures to reduce light pollution, especially during the fledging period (April), have been proposed (Le Corre et al. 2002). Since 2004, the community of Cilaos, close to the species's colonies, has taken part in efforts to reduce lighting, and there has been a corresponding decrease in the numbers of grounded birds. More recently the National Park of Réunion Island has implemented a joint initiative to reduce light pollution at the scale of the whole island. All known breeding colonies are fully protected since 2007 within the core area of the National Park. Finally, and most importantly, a LIFE+ project is currently underway (2015-2020) to develop various conservation actions, including the control of feral cats at and near most breeding colonies

Conservation Actions Proposed

Carry out surveys to obtain an up-to-date population estimate. Conduct regular surveys to monitor population trends. Control predators, particularly cats at breeding colonies (V. Bretagnolle in litt. 1999, V. Bretagnolle in litt. 2007). Cat control at breeding colonies is required year-round, particularly during the non-breeding season when efforts are likely to have the most effect due to the reduction of other available prey (Pinet et al. 2009). Legislative change is first required to allow the control of feral cats, as these are currently protected alongside domestic cats under French legislation (Pinet et al. 2009). Instigate a comprehensive education program to demonstrate the impact of feral cats to the local population (Pinet et al. 2009). Ensure that a protected area is declared as soon as possible to include all colonies (Pinet et al. 2009). Continue rescue programme of young birds attracted by lights (Le Corre et al. 2002). Investigate light-reduction programmes either through light-shielding or light-restriction during April and May (M. Le Corre in litt. 1999, Le Corre et al. 2002), and consider adjusting its direction, intensity and colour, and the use of temporary black-outs (Salamolard et al. 2007). 

Citation: BirdLife International. 2016. Pterodroma baraui. The IUCN Red List of Threatened Species 2016: e.T22698035A93656788. . Downloaded on 23 May 2018.
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