Data Zone
Justification of Red List category
This species is listed as Vulnerable because improved knowledge indicates that, within its small population, the largest sub-population numbers fewer than 1,000 individuals, with the overall population suspected to be in decline owing to the effects of introduced species.
Population justification
Unpublished data from the Fiji IBA project (G. Dutson in litt. 2005) suggest that the global population numbers 1,000-10,000 individuals, roughly equivalent to 670-6,700 mature individuals.
Trend justification
There are insufficient data available to quantify the species's population trend, but it is considered to be undergoing a slow to moderate decline owing to predation by introduced mammals.
Pterodroma brevipes is presently known to breed only on Kadavu and Gau (Fiji), Vanua Lava and Tanna (Vanuatu). Breeding may still occur at Tau (Western Samoa), Raratonga (Cook Islands), Â Makira (Solomon Islands) (J. Hobbs in litt. 2009) and other hitherto undiscovered sites. It is known to have bred historically on Viti Levu, Kadavu, Ovalau, and Vanuabalavu (Fiji).
Surveys in 2011 recorded the species coming to lights and/or acoustic cues on Kadavu, Koro, Matuku, Moala and Totoya (Fiji), with breeding strongly suspected from these islands (O'Brien et al. 2016). During surveys for this species at the historical breeding site of Ovalau (July 2004) none were seen (G. Dutson in litt. 2005). On Gau island, 165 birds were attracted to lights on four nights in April-May 1984 (Watling 1985). The species was thought to have been extirpated from Viti Levu and Vanua Levu through predation by introduced Small Indian Mongoose Herpestes auropunctatus. However, on Viti Levu, petrels have been seen flying inland during the day, one freshly killed specimen was found in 1971 and breeding birds were found on Vanua Levu (Watling 1986, Tennyson et al. 2012). The one other Fijian island with a historical specimen record but no mongooses, Vanuabalavu (Watling 1986), has not been surveyed in recent years (Watling 1986, D. Watling in litt. 2000, G. Dutson in litt. 2005). A series of specimens from Vanuatu from 1859 to 1936 include breeding birds from the southern islands of Tanna and Aneityeum (=Anatom), and birds from Efate and at sea off Mere Lava (Banks Islands) (Bregulla 1992). Recent records from Vanuatu include two individuals seen off Efate on 11 March 1971 (Trodden in Bourne and Dixon 1975) and some at sea in 2004 (D. Hobcroft in litt. 2004). There have been no recent thorough surveys of the Vanuatu breeding islands but local people on Tanna reported that hole-nesting birds were very rare in 1998 (G. Dutson in litt. 2005). A visit to Tanna in July 2008 proved that the species still breeds in the mountains in the south-west of the island (S. Totterman pers. comm.).
The newly-described taxon P. b. magnificens is known to breed on Vanua Lava, and was found to be relatively abundant during an expedition in 2009, with 180 sighted at sea (Bretagnolle and Shirihai 2010) and several individuals were caught returning to burrows during a 2011 expedition to the island (Tennyson et al. 2012). P. b. magnificens may also breed in Gaua in the Banks Islands (Bretagnolle and Shirihai 2010).
Outside Fiji and Vanuatu, there are historical breeding specimens from Makira (Solomon Islands). Extensive work with local communities on Makira revealed no knowledge of the species but nine were seen at sea between Makira and the Santa Cruz islands on 3 October 2004 (G. Dutson in litt. 2005). The species previously nested on Rarotonga (Cook Islands), but only a small relict population remained in 1990, which is now reported to have gone extinct (McCormack 1992, M. Imber in litt. 2006, E. Saul in litt. 2006). It may also breed on the Austral Islands (French Polynesia), Moorea, Tahiti and Samoa, although there are no confirmed records (M. Rauzon in litt. 2005, M. Imber in litt. 2006). Reports from Tau in American Samoa may refer to the Herald Petrel P. heraldica (Engbring and Ramsay 1989). It has been suggested that the birds found in the Solomon Islands and French Polynesia may be P. caledonica rather than P. brevipes (V. Bretagnolle in litt. 2005), although this is disputed (M. Imber in litt. 2006). Regardless of the taxonomic status of P. brevipes, it is undoubtedly rare, and its population has recently been estimated at 1,000-10,000 individuals (G. Dutson in litt. 2005).
The non-breeding range is thought to be tropical Pacific between 10A°N and 10A°S as far as the Galapagos Islands.
It nests on Kadavu and Gau, Fiji, Vanua Lava and Tanna, Vanuatu between 100 and 500 m, in burrows on steep, well-forested slopes (MacGillivray 1860, Watling 1986, Tennyson et al. 2012). Young have been found in the nest on Fiji from May to August (MacGillivray 1860, Watling 1986), although on Vanuatu small downy young were found in February (MacGillivray 1860, Brooke 2004). It is perhaps relatively sedentary, tending to remain close to the breeding islands, although some are recorded to have dispersed east between about 10oN and 15oS almost to the Galápagos (Brooke 2004). Its diet is little known, but is thought to consist chiefly of cephalopods and fish (MacGillivray 1860).
Invasive species represent one of the greatest threats to the Collared Petrel. Evidence of nest predation by rats has been recorded and rats may be the most significant current threat faced by the species (Tennyson et al. 2012). The Small Indian Mongoose appears to have caused rapid declines in the past and is considered a major factor in the present distribution and potential breeding distribution of the species. Cats appear to be a significant predator of chicks and adults, with birds killed by cats observed on Vanua Lava (Tennyson et al. 2012). Dogs and pigs have been suggested to cause declines however, it is unsure whether they would be able to access the majority of the population which are restricted to relatively inaccessible locations. Goats are also suggested to have caused a decline, possibly through impacting the suitability of nesting locations but this is unlikely to have had a significant impact. As with other Pacific petrels, Collared Petrel was heavily exploited for food by local communities with harvests recorded from Kadavu (O’Brien et al. 2016), the Banks Islands and Tanna (Totterman 2009). On Tanna, small numbers of young birds have been killed as part of a ritual (V. Bretagnolle in litt. 2005).
Conservation Actions Underway
In 2011 targeted searches of potential breeding islands in Fiji were completed. This was followed by a study funded by the Critical Ecosystem Partnership Fund of birds attracted to lights at the historical breeding site Nabukelevu/Mt Washington on the island of Kadavu, Fiji. Nest boxes and acoustic attraction has been installed on Nabukelevu. Nest boxes and acoustic attraction have also been installed on the predator-free island of Vatu-i-ra, Fiji (BirdLife International 2012). NatureFiji/MareqetiViti have been studying the species on Gau, initially recording numbers attracted to light during the breeding season and subsequently nest-finding with trained dogs. This has identified 88 breeding burrows. Active and passive search methodologies have been developed and published for rapid assessment of Collared Petrel presence (O’Brien et al. 2016).
Conservation Actions Proposed
Conduct surveys during the breeding season using published methods to determine its status on all islands where it is known or suspected to occur. Supplement field surveys with searches using trained dogs to find active burrows on islands where breeding is suspected. Assess breeding success and predation levels at sites where breeding is confirmed. Control introduced mammals around known nesting sites. Advance a project to install predator-proof fencing at key sites. Deploy further acoustic attraction devices at predator-free sites within its range (e.g. Monuriki, Fiji). Clarify taxonomy.
30cm. Small and variable black-capped gadfly petrel of the Cookilaria group. Forehead white merging into dark brownish-grey cap and sides of cheeks, upperparts grey. Underparts highly variable: pale morphs almost all white, intermediate morphs have dark collar across the chect, dark morphs have dark grey underparts except whitish chin and throat. Similar spp. Distinguished from other Cookilaria species by the broad dark leading margin to the underwing. Tail longer in relation to wing than in Gould's Petrel P. leucoptera. Voice Very similar to Gould's Petrel. Flight calls include a staccato ti-ti-ti, a low moan, a thick low purring call, and a cher-cher.
Text account compilers
Moreno, R., Stuart, A., Tarzia, M, Taylor, J., Temple, H., Anderson, O., Fjagesund, T., Ekstrom, J., Harding, M., Butchart, S., Hermes, C., Mahood, S., Martin, R.
Contributors
Totterman, S., Imber, M., Watling, D., Rauzon, M., Saul, E., Dutson, G., Bretagnolle, V., Cranwell, S., Bird, J.
Recommended citation
BirdLife International (2024) Species factsheet: Collared Petrel Pterodroma brevipes. Downloaded from
https://datazone.birdlife.org/species/factsheet/collared-petrel-pterodroma-brevipes on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.