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Range DescriptionProcellaria conspicillata is essentially confined to the South Atlantic Ocean north of the South Polar Front, predominantly between 25-41°S (ACAP 2009). It breeds only on the high western plateau of Inaccessible Island, Tristan da Cunha, St Helena (to UK). In 1949-1950, the population was estimated to be at least 100 pairs, probably considerably more (Rowan et al. 1951). In 1982-1983, it was estimated at c.1,000 pairs (Fraser et al. 1988, Ryan 1998). In 1999, 6,000-7,500 burrows were counted (c.60% occupied), but failures prior to this stage and the presence of non-breeders confound an accurate population estimate (Ryan and Moloney 2000). A repeat survey in 2004 counted 11,000-12,000 burrows, with 14,400 counted in 2009-2010 (Ryan et al. 2011). Assuming an occupancy of 90% this suggests a breeding population of 20,000 individuals (Ryan et al. 2006). An extrapolation from snapshot censuses conducted in waters off Brazil in 1997-1999 suggested a total population of 38,000 ± 7,000 (Leandro Bugoni in litt. 2006). This population increase over time is thought to have been initiated by the eradication of pigs from Inaccessible Island. Between 1999-2004, the species may have increased by up to 45% (Ryan et al. 2006) but the toll taken by bycatch in longline fisheries is poorly understood. Most birds disperse to the waters off southern Brazil outside the breeding season, with small numbers recorded off the west coast of southern Africa. In the 19th century, it may have occurred throughout the Indian Ocean, possibly breeding at Amsterdam Island (French Southern Territories), and was also collected at sea off Australia (Enticott and O'Connell 1985, Ryan 1998).