Justification of Red List Category
This species is listed as Vulnerable because owing to its very small breeding range, it is highly susceptible to stochastic events and human activities. Any evidence of population declines would likely lead to its uplisting.
14,400 nesting burrows were counted on Inaccessible Island in 2009-2010 (Ryan and Ronconi 2011). Assuming a burrow occupancy of 90%, this equates to a breeding population of approximately 20,000 breeding birds. The overall population is estimated at around 38,000 ± 7,000 individuals; 7,000 individuals were present at sea off Brazil based on survey data from 1997-1999 (L. Bugoni in litt. 2006).
Between 1999-2004, the numbers of breeders may have increased by up to 45% (Ryan et al. 2006), but the toll taken by bycatch in longline fisheries is poorly understood. Bycatch may affect juveniles disproportionately more than adults; a bias that will not be reflected at the breeding grounds for several years.
Procellaria 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 and Ronconi 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 (L. 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).
Behaviour Procellaria conspicillata breeds annually and is active in colonies from September to March. Breeding phenology has not been well studied, but egg-laying commences in October, with hatching in December and the chicks fledge in March (ACAP 2009). Habitat Breeding It breeds in wet heath at 250-500 m (P. G. Ryan in litt. 2016). Burrows are along the banks of river valleys (Fraser et al. 1988) but most pairs breed in loose colonies among bogfern Blechnum palmiforme vegetation, where their burrowing activity creates distinctive marshy areas dominated by Scirpus sedges (P. G. Ryan in litt. 2016). Diet It feeds on cephalopods, decapod crustaceans and small fish (Hagen 1952). A total of 121 food items (five fish and 116 cephalopods) were found in the diet of seven longline-caught birds off the coast of Brazil (Colabuono and Vooren 2007).
Feral pigs may have caused the apparent extirpation of Procellaria petrels from Amsterdam Island. They are also likely to have had an impact on Inaccessible throughout most of the 19th and early 20th centuries (Fraser et al. 1988, Ryan 1998), before their removal in the 1950s, as demonstrated by the species’ subsequent and continuing consistent increase in population.The Spectacled Petrel has high overlap between its distribution and longline fishing effort off southern Brazil, supported by satellite telemetry (L. Bugoni in litt. 2009), as well as a relatively high attendance rate to many fishery vessels (Bugoni et al. 2008). Despite occasionally being caught as bycatch, the rate is very low, potentially because this species is adept at avoiding capture. The population of Spectacled Petrel seems to be increasing and, as such, it appears that bycatch is not having significant population impacts in the species.
Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Inaccessible Island is a nature reserve and, although Tristan Islanders retain the right to collect driftwood and guano, other access is restricted (Cooper et al. 1995). A repeat of the 1999 breeding bird census on Inaccessible Island was conducted in 2004. Ongoing studies attempt to quantify the current level of bycatch in fisheries off southern Brazil.
55 cm. Large, black petrel with white bands around face. Sooty-black with white face markings. Horn or yellow bill. Similar spp. Provided face markings seen, easily distinguished from other petrels. Voice Similar to White-chinned Petrel P. aequinoctialis, but slightly deeper-pitched.
Text account compilers
Hermes, C., Martin, R., McClellan, R., Moreno, R., Stattersfield, A., Anderson, O., Stuart, A., Sullivan, B., Symes, A., Bird, J., Black, A., Benstead, P., Butchart, S., Calvert, R., Ekstrom, J., Fjagesund, T.
Wanless, R., Croxall, J., Hilton, G., Cooper, J., Ryan, P.G., Bugoni, L., Favero, M.
BirdLife International (2021) Species factsheet: Procellaria conspicillata. Downloaded from http://www.birdlife.org on 16/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/01/2021.