EN
Sooty Albatross Phoebetria fusca



Justification

Justification of Red List Category
This species qualifies as Endangered owing to a very rapid decline over three generations (90 years), probably due to interactions with fisheries. Since 1980, three sites (Crozet, Marion and Gough) have witnessed severe declines, although the population at Prince Edward may have increased between 2002-2009. However, high variability in population counts between years necessitates caution and further data are required before a change in status should be considered.

Population justification
The population is estimated at 10,617 - 14,328 breeding pairs.

Trend justification
On Possession Island (Crozet), the population declined by 58% between 1980 and 1995 (Weimerskirch and Jouventin 1998) and continues to decline, although at a slower rate (Delord et al. 2008). This equates to an 82% decline between 1980 and 2006 at an average rate of 4.2% per year (Delord et al. 2008). Although since 2006 the population has been increasing again at 2.7% per year, the numbers remain low compared to those of 20 or more years ago. On Marion Island, the population declined by 25% from 1990-1998 (a decline of about 2.6% per year: Crawford et al. 2003) and continued to decline at about 3% per year from 1998 to 2006 (Schoombie et al. 2016). However, from 2006 to 2014, the population has increased at c. 4% per year (Schoombie et al. 2016). On Gough Island (c.36% global population), the population appears to have decreased by over 50% from 1972-2000 (Cuthbert and Sommer 2004a), although recent counts of breeding birds indicates the number of breeding pairs remained stable from 2000 and 2015 (Cuthbert et al. 2014). Limited counts have been made on Tristan and Inaccessible, and indicate a population of c.3,157 (ACAP 2012). Overall, these declines equate to 60% over three generations (90 years), with a trend start date of 1960. However, this species, being a biennial breeder, has a highly variable breeding population between years. Better data are required from Gough and Prince Edward Islands, in particular whether the population on Prince Edward is increasing. The long life expectancy of the species makes it difficult to determine the period over which an analysis of trends should be conducted.

Distribution and population

Phoebetria fusca breeds on islands in the South Atlantic and Indian Oceans. The total annual breeding population is estimated at 10,617 - 14,328 pairs (ACAP 2012), including c.2.500-5,000 pairs on Gough Island (Cuthbert et al. 2014), 3,157 pairs in the Tristan da Cunha group (to the U.K.) (ACAP 2012), c. 1,450 pairs on Prince Edward and c. 1,700 pairs on Marion Island (South Africa) (ACAP 2012), 2,080-2,200 pairs on the Crozet Islands (Delord et al. 2008), and 470 pairs on Amsterdam Island (French Southern Territories) (Delord et al. 2008). The pelagic distribution is mainly between 30°S and 60°S in the southern Indian and Atlantic Oceans, with a southern limit of c. 65°S near Antarctica and a northern limit of c. 20°S. Adults move north in winter from sub-Antarctic to subtropical seas, whereas immature birds tend to remain in subtropical seas year round. The species infrequently disperses eastward to the Tasman Sea and New Zealand waters (ACAP 2009).

Ecology

Behaviour It breeds in loose colonies of up to 50-60 nests (Marchant and Higgins 1990). The breeding season extends through summer, eggs are laid in October and November, hatch in early to mid-December and chicks fledge in May (ACAP 2009). Successful pairs seldom breed in the following summer (Ryan 2007). A single egg is laid, with no replacement laying. Adults make a combination of long commuting flights early in the incubation period, looping searching flights later in incubation and linear searching during chick brooding (ACAP 2009).
Habitat Breeding It breeds on cliffs or steep slopes where it can land and take off right next to the nest (Marchant and Higgins 1990).
Diet Squid, fish, crustaceans and carrion all feature prominently in the diet, although proportions of each vary between years and locations (ACAP 2009).

Threats

Both adults and juveniles have been caught as bycatch by Japanese longline vessels fishing inside and beyond the Australian Fishing Zone (Gales et al. 1998) and some are killed on tuna longlines off southern Africa (Ryan et al. 2003). However, only one bird (of 1,500 examined) is known to have been killed by vessels with observers in the Prince Edward fishery (P. G. Ryan in litt. 1999). One banded bird has been caught by a Chinese Taipei longline vessel fishing in the Indian Ocean (Delord et al. 2008). The population on Possession Island, Crozet Islands has nevertheless been found to be significantly and negatively affected by fisheries bycatch, particularly adult survival rates (in the absence of fishing effort, predicted adult survival was 0.902 as opposed to 0.884) (Rolland et al. 2010), but rates of decline are not considered sufficient to exceed slow, significant declines (R. Phillips pers. comm. 2018).

On-land threats include introduced predators and infectious diseases. Both avian cholera Pasteurella multocida and Erysipelas Erysipelothrix rhusiopathiae are present and cause periodic reduction in reproductive output, considered sufficient to be driving a slow decline in population size in affected colonies (Weimerskirch 2004). Introduced rats and cats on the Kerguelen Islands are not known to affect the species, but cats and rats on Amsterdam Island are known to impact the species sufficiently to cause population-level changes (ACAP 2009). Rats are also present on Amsterdam Island but their impact on surface-nesting albatross is unclear (R. Phillips pers. comm. 2018). On Marion Island, up to 5% of chicks are killed my mice each year, and the rate is likely to increase unless mice are eradicated.

Conservation actions

Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Population monitoring and foraging studies are being undertaken at Possession, Amsterdam and Marion. The species is protected in Tristan da Cunha (J. Cooper in litt. 1999, P. G. Ryan in litt. 1999). Gough is a World Heritage Site and the Prince Edward Islands are a Special Nature Reserve. Inaccessible and Gough Islands are nature reserves. A population estimate was made at Gough during 2000-2001, and a repeatable monitoring protocol was devised (Cuthbert and Sommer 2004b). Monitoring has been repeated in 2003 and 2006 at Gough. Gough and Tristan birds have also been remotely-tracked to determine at-sea distribution. A project on Tristan da Cunha (2004-2006) is undertaking population counts. In 2007, Crozet, Amsterdam and Kerguelen Islands were declared Nature Reserves.

Conservation Actions Proposed
Repeat standardised population surveys at all key sites, most notably Gough and Tristan da Cunha. Determine foraging distribution of the species and its overlap with longline fisheries. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, particularly via intergovernmental mechanisms such as ACAP, CCAMLR, FAO, and Regional Fisheries Management Organisations such as the tuna commissions in the Atlantic and Indian Oceans (ICCAT, IOTC).

Identification

85 cm. Medium-sized, sooty-brown albatross with diamond-shaped tail. Adult is uniform sooty-brown, slightly darker on sides of head. White crescent above, behind eye. Black bill with orange or yellow sulcus. Juvenile and immature essentially as adult. Similar spp. Dark, pale-billed giant-petrels are more bulky with shorter, stubbier wings. Light-mantled Sooty Albatross P. palpebrata has violet or bluish sulcus and paler mantle. P. fusca with worn plumage difficult to distinguish. Voice Two-syllable skycall given from near nest-site.

Acknowledgements

Text account compilers
Small, C., Stattersfield, A., Stuart, A., Sullivan, B., Symes, A., Anderson, O., Fjagesund, T., Hermes, C., Butchart, S., Martin, R., Calvert, R., Moreno, R., Nel, D.

Contributors
Hilton, G., Croxall, J., Ryan, P.G., Cuthbert, R., Weimerskirsch, H., Bond, A., Misiak, W., Crawford, R., Cooper, J.


Recommended citation
BirdLife International (2020) Species factsheet: Phoebetria fusca. Downloaded from http://www.birdlife.org on 27/10/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/10/2020.