Justification of Red List Category
This species is listed as Near Threatened because it is suspected to have a moderately small range, potentially restricted to only a few breeding locations. If this was found to be in decline or smaller than suspected, the species may qualify for uplisting to a higher threat category.
This is not a particularly rare bird at sea, and the total population runs into thousands, if not tens of thousands. Based on this judgement, the population is placed in the range 2,500-9,999 mature individuals.
The current population trend is unknown (see Symes et al. 2015).
Bulweria fallax is a poorly known species of the north-west Indian Ocean, occurring widely offshore in the Arabian Sea and Gulfs of Aden and Oman, where it is often the commonest pelagic seabird (Porter et al. 1996). It occurs commonly east of 58°E in the Arabian Sea as far as the Maldive Ridge, regularly east to southern India and Sri Lanka, and regularly, albeit at low densities, to the eastern Indian Ocean in the Bay of Bengal and off north-western Australia (Van den Berg et al. 1991, Ryan et al. 2013, Lavers et al. 2014). During the summer monsoon (May-September) it congregates off the Socotra archipelago (Yemen), where a breeding colony of at least c.50 pairs was recently discovered (Taleb 2002) and where c.3,000 pairs are now estimated to nest locally on mainland cliffs (Al Saghier et al. unpublished), and also off the Halaaniyaat islands (southern Oman), where it may nest (or on the Arabian mainland adjacent) (Gallagher 1985). In recent years, work in UAE waters of the Gulf of Oman has revealed erratic influxes of up to 600 birds in Sept – Dec; the species is either very rare or absent for much of the rest of the year. Similar sea-cliffs within its range on the coast of Somalia deserve investigation for breeding colonies (PERSGA/GEF 2003). A population of unidentified Bulweria petrels, most likely B. fallax, was discovered around Comoro archipelago (Shirihai et al. 2015), with most birds being in active moult, but not all. These individuals, however, show plumage characteristics that do not match with B. fallax.
It frequents open sea all-year-round, only approaching land during the breeding season, at dusk and after dark (Taleb 2002, PERSGA/GEF 2003). Its foraging areas are poorly known, but presumably related to highly productive areas of oceanic upwelling (PERSGA/GEF 2003). It flies low, taking food from the surface of sea, probably mainly plankton e.g. fish eggs, ctenophores and polychaete worms (PERSGA/GEF 2003).
Seabirds, including this species, were formerly exploited for food and medicinal use (at a subsistence level [Al-Saghier et al. 2000]) on the Halaaniyaat islands (Gallagher 1985) and Socotra (Al-Saghier et al. 2000, Porter et al. in prep.), but this practice appears to be discontinued due to the availability of cheap poultry and the danger of climbing the cliffs (Taleb 2002). Non-native predators (e.g. rats Rattus spp. and Feral Cats Felis catus) are probably a limiting factor on the species’ breeding population size (Al-Saghier et al. 2000), although their impact on the Socotran subpopulation may have stabilised long ago, given the long period (over 2,000 years) of coexistence. Mortality and ecosystem degradation resulting from marine oil spills are potential threats.
Conservation Actions Underway
No actions are currently known.
Text account compilers
Bennett, S., Benstead, P., Calvert, R., Fjagesund, T., Martin, R., Anderson, O., Moreno, R., Symes, A., Taylor, J.
Bretagnolle, V., Nisbet, I., Clarke, R., Campbell, O.
BirdLife International (2019) Species factsheet: Bulweria fallax. Downloaded from http://www.birdlife.org on 13/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 13/11/2019.