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).

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).

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).