Stercorcarius parasiticus – SGIWEN Y GOGLEDD – Passage migrant.
The Arctic Skua has a circumpolar Arctic breeding distribution extending southwards to northern Scotland. Migrants seen passing through British waters are en route to and from Atlantic wintering areas, principally south of the equator.
Mathew (1894) noted just one record of an Arctic Skua, shot at Goodwick, but gave no date. Lockley et al (1949) considered it to be occasional off Skokholm and Grassholm, mainly in August and September but sometimes in May or June.
A mean of 10 per annum was recorded in the county between 1953 and 1975, during a period when little seawatching was conducted. The low detection rate being linked to a paucity of watching was emphasised when Saunders (1976) noted 45 passing Strumble Head on the 8th September 1974. Watching at this headland became more frequent from 1978, with regular autumn observations from 1980 onwards. The annual average total of Arctic Skuas recorded in Pembrokeshire between 1980 and 2003 rose to 235, 90% of them being seen at Strumble Head, passage taking place between July and November, the majority between August and October.
Age and or morph was recorded for the bulk of the Arctic Skuas seen at Strumble Head between 1980 and 2006. Adults made up 67% of the total, of which 31% were light–phase, 33% dark–phase and 3% classified as intermediates, the remaining 33% of the total were predominantly juveniles, though some first and second year birds were identified.
© 2010 G H Rees