THE IMPACT OF OIL SPILLS ON SEABIRDS
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West of Britain, Ireland and Irish Sea
 recently well covered, vulnerability atlas available

Seabirds in the area: internationally important breeding populations of auks, cormorants and
gannets. Some breeding seaduck. Internationally important pathway for numerous species of
migratory seabirds. Wintering auks (pelagic and coastal), divers, seaduck, cormorants (all
coastal) and some gannets (pelagic).

Species of particular conservation concern: Manx Shearwater, European Storm-petrel, Leach’s
Storm Petrel

Standardised studies of seabirds at sea: extensive studies of seabirds at sea (Webb et al. 1995a,
Pollock et al. 1997), continued in recent years (Mackey et al. 2004); information on wintering
coastal seabird and waterfowl concentrations (Lack 1986).

OVI evaluation and area sensitivity: vulnerability atlas produced, using species specific OVI
analysis and seabird abundance data on a monthly basis (Webb et al. 1995b).

Anticipated sensitivity to chronic oil pollution: locally very high; clearly identified seasonal and
spatial patterns in sensitivity published (Webb et al. 1995b).
Species of particular conservation concern:
Manx Shearwater Puffinus puffinus This species has a large range, with an estimated global breeding Extent of
Occurrence of 50,000-100,000 km 2. It has a large global population estimated to be at least 1,000,000
individuals (Brooke 2004). Global population trends have not been quantified, but the species is not
believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining
more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least
Concern (BirdLife International 2007a). Within Europe, the major part of the breeding population is
concentrated at a few sites, some of the largest being in Ireland (29,000-49,000p) and especially in
Scotland (220,000-250,000p; SPEC Category 2, status (Localised); Brooke & Tasker 1994)
European Storm-petrel Hydrobates pelagicus has a large global population estimated to be 840,000 individuals
(Fishpool and Evans 2001). About 90% of the known breeding population is concentrated in the Faroe
Islands (Denmark) (150,000-400,000 pairs), United Kingdom (20,000-150,000 pairs), Ireland (50,000100,000 pairs) and Iceland (50,000-100,000 pairs), with smaller colonies elsewhere. This species has a
large range, with an estimated global breeding Extent of Occurrence of 50,000-100,000 km2. It nests on
remote islands that are largely free of mammalian predators. Despite evidence of population declines in
some areas, the species is not believed to approach the thresholds for the population decline criterion of
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THE IMPACT OF OIL SPILLS ON SEABIRDS
HANDBOOK DOCUMENTS
the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the
species is evaluated as Least Concern (BirdLife International 2007b).
Leach’s Storm-petrel Oceanodroma leucorhoa. This species has a large range, with an estimated global breeding
Extent of Occurrence of 50,000-100,000 km². It has a large global population estimated to be 8,000,000
individuals. Global population trends have not been quantified, but the species is not believed to approach
the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten
years or three generations). For these reasons, the species is evaluated as Least Concern (BirdLife
International 2007c). Within Europe there are only a few colonies, all on remote islands close to oceanic
feeding grounds. An estimated 50,000p breed in the United Kingdom (SPEC Category 3, status
(Localised); Tasker 1994, Mitchell 2004)
References
BirdLife International 2007a. Species factsheet: Puffinus puffinus. Downloaded from http://www.birdlife.org on 27/10/2007
BirdLife International 2007b. Species factsheet: Hydrobates pelagicus. Downloaded from http://www.birdlife.org on 27/10/2007
BirdLife International 2007c. Species factsheet: Oceanodroma leucorhoa. Downloaded from http://www.birdlife.org on
27/10/2007.
Mitchell P.I. 2004. Leach's Storm-petrel Oceanodroma leucorhoa. In: Mitchell P.I., S.F. Newton, N. Ratcliffe & T.E. Dunn (eds)
Seabird populations in Britain and Ireland: 101-114. T. & A.D. Poyser, London.
Tasker M.L. 1994. Leach's Petrel Oceanodroma leucorhoa. In: Tucker G.M. & Heath M.F. (eds). Birds in Europe - their
conservation status: 76-77. Birdlife Conservation Series No. 3, Birdlife International, Cambridge.
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