Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Brooke (2004) estimated the global population to number at least 3,000,000 individuals.
The population is suspected to be stable in the absence of evidence for any declines or substantial threats.
The Blue Petrel is found throughout southern Oceans. Breeding sites include the Crozet Islands and Kerguelen Island (French Southern Territories), Marion Island and Prince Edward Island (South Africa), Macquarie Island (Australia) and South Georgia (Georgias del Sur). Adults are perhaps mainly sedentary, though young birds are more dispersive (del Hoyo et al. 1992).
Breeding begins in September, occuring in colonies where it nests in long burrows excavated in soft soil under grass tussocks (del Hoyo et al. 1992). Foraging during the chick-rearing period at the Kerguelen Islands involves regular alternation between short trips in the vicinity of the island and long trips to Antarctic waters. Short trips enable an increase of chick-feeding frequency at the expense of energy reserves built up during long trips. Diet comprises of crustaceans (especially krill), fish, squids and some insects (del Hoyo et al. 1992, Cherel et al. 2002).
Impacts of rat and cat predation appears severe and cats appear to have contributed to or caused the extirpation from several islands (Carboneras et al. 2018). The European Rabbit may also severely impact Blue Petrels on the islands where it is present, shown by the eight-fold increase in Blue Petrel population on Vert Island within six years of rabbit eradication. Further to this, habitat degradation by the native Antarctic Fur Seals on South Georgia, which have dramatically increased in the past decades, causes the loss of breeding sites and also may cause the loss of nests.
Text account compilers
Ekstrom, J., Fjagesund, T., Butchart, S., Calvert, R., Hermes, C., Martin, R., Newton, P., Stuart, A.
BirdLife International (2019) Species factsheet: Halobaena caerulea. Downloaded from http://www.birdlife.org on 20/05/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/05/2019.