Stercorcarius parasiticus – SGIWEN Y GOGLEDD – Passage migrant. Not recorded in February and March
Mathew (1894) recorded just one Arctic Skua, but Lockley et al. (1949) commented that they were occasionally seen off Skokholm and Grassholm, usually in August and September, sometimes in May and June. This pattern continued to be recorded, but with autumn occurrences proving to be annual. Records never involved more than four birds on any occasion until ten were seen passing Strumble Head on 11 September 1971 and 50 on 8 September 1974. Saunders (1976) concluded that the number recorded was limited by the “meagre amount of observation carried out from our headlands like Strumble and St David’s”. Subsequent regular and frequent watching at Strumble Head has fully confirmed this view (see Table 13).
There is a north to south passage out of the Irish Sea in the autumn, from mid-July to 20 November, up to ten per day being a typical tally for Strumble Head. However, south-west gales can bring larger numbers to Cardigan Bay. These birds fly out past Strumble Head when the wind veers round north of west, and 30-70 in a day can be seen in such conditions, with 103 passing on 3 September 1983. Like the Pomarine Skua the majority pass out to sea once clear of the Bishops but small numbers, up to six per occasion, occur along the west coast between Skokholm and Grassholm with up to ten in a day further out at the Smalls. A few wanderers turn in to explore the south coast and have even been known to enter the Cleddau Estuary.
Spring passage is small in volume, when one or two can be detected off any of the coasts between 9 April and June or early July, the late birds possibly being non-breeders.
One was seen at Strumble Head on 15 January 1984 and on 20 December 1991.
SAUNDERS, D.R. 1976. A brief guide to the birds of Pembrokeshire. Five Arches Press.