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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to 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 4,000,000 individuals. The European population is estimated at 77,800-111,000 pairs, which equates to 156,000-221,000 mature individuals (BirdLife International 2015).
The population is suspected to be in decline owing to predation by invasive species. In Europe, the population size is estimated to be decreasing by less than 25% in 46 years (three generations) (BirdLife International 2015).
This species breeds on remote islands in the south Atlantic, such as Tristan da Cunha (U.K.) and also on the coast Australia and New Zealand. There are north Atlantic colonies on the Cape Verde Islands, Canary Islands, Spain, and Savage Islands, Portugal. Outside the breeding season birds from the Atlantic have been seen off the east coast of North America and South America, and off the western coast of Central Africa. Breeders from Australia and New Zealand range as far as the northern Indian Ocean and the north-west coast of South America (del Hoyo et al. 1992).
This marine species can normally be found over pelagic waters except when at breeding colonies. It feeds mostly on planktonic crustaceans and small fish, but will also feed on squid. It feeds mainly on the wing by pattering and dipping at night. It rarely follows ships, but is known to follow cetaceans. It generally breeds in colonies during spring and summer, forming burrows in flat sand areas with low herbaceous vegetation, but also in rocky areas and on slopes. Movements are variable, but all populations disperse post-breeding and tend to travel far (del Hoyo et al. 1992).
Egg depredation by the house mouse, an invasive predator, has been found to be the main apparent cause of hatching failure (Campos and Granadeiro 1999) and is believed to heavily impact reproductive success where mice are present. White-faced Storm-petrels have been found to have one of the highest rates of plastic contamination, with up to 53 particles per bird equal to 96% of their relaxed gizzard volume (Furness 1985 in Azzarello and Van Vleet 1987). The presence of plastics in a bird’s gizzard may cause gastrointestinal blockage (Day 1980 in Azzarello and Van Vleet 1987); depression of feeding activity by sustaining stomach distention, a stimulus normally associated with satiety (Sturkie 1965 in Azzarello and Van Vleet 1987, Ryan 1988); and a reduction in meal size (Ryan 1988). The weight of plastic consumed remained stable between 1987 and 2004 (Ryan 2008), and no population level impacts have been established.
Conservation Actions Underway
EU Birds Directive Annex I. Bern Convention Appendix II. The species is listed as Vulnerable in the Spanish Red Data Book. The current breeding colonies in Spain are covered by the ENP (Espacios Naturales Protegidos) network. In 1992 the Department of the Environment launched a programme to monitor the population and breeding success of the species. The European Union has granted the governing body of Lanzarote funding for a LIFE project in the Natural Park of the Chinijo Archipelago which provided some conservation actions that benefit the species. Chief among them was the eradication of rabbits from Clara Mountain Island, which has been a great success (Madroño et al. 2004). The colony at Mud Island, Victoria has been legally protected as early as 1903 (Carboneras et al. 2016).
Conservation Actions Proposed
Human exploitation should be terminated and eradication of introduced predators on all breeding islands is also recommended (Carboneras et al. 2016). Develop and publish a conservation plan for the species and ensure its guidelines are implemented. Planning tools of Espacios Naturales Protegidos (Spain) should be developed and approved to restrict access to breeding sites. Light-reducing mechanisms should be developed in urban areas next to the breeding areas and injured birds recovered (Madroño et al. 2004). Programmes of eradication or control of cats and rabbits on islets with the species should be set up (Madroño et al. 2004, Carboneras et al. 2016) and mechanisms established to prevent the spread of potentially dangerous mammals, especially on Clara Mountain Island. Continue regular monitoring of the population and reproductive success, as well as conducting surveys in potential habitats in order to detect new colonies (Madroño et al. 2004).
Text account compilers
Stuart, A., Calvert, R., Butchart, S., Ekstrom, J., Fjagesund, T., Hermes, C., Martin, R., Ashpole, J, Miller, E.
BirdLife International (2021) Species factsheet: Pelagodroma marina. Downloaded from http://www.birdlife.org on 21/09/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/09/2021.