Arctic Skua (Stercorarius parasiticus)

The vast majority of the Arctic Skuas that breed in, or pass through, Britain and Ireland end up crossing the equator to winter in the south Atlantic, mainly off southern Africa but with some birds on the south American coast (Migration Atlas). In Cheshire and Wirral, most birds are seen off the Wirral coast in autumn, acrobatically harassing terns to disgorge their latest catch, and winter records are rare. The two birds seen during this Atlas period (both in winter 2006/ 07) were the first for six years: one was seen off Hilbre (SJ18Z) and another on 4 January 2007 flew in the mouth of the Mersey off Egremont shore, crossing tetrads SJ39B and SJ39G.

The first winter bird on record in the county appears to be at Hilbre on 4 December 1960 (Bell 1962). County bird reports from then on confirm its scarcity, with just twelve winter records in forty years from 1964 to the start of this Atlas. Four of these were in an exceptional period on separate dates from 17 November to 7 December 1982, two in the Mersey mouth and two inland. In total, there have been five records in late November, four in December, two in early January (4 January 1970 and 1 January 1998), and the only February record is an immature bird, seen from a ship in Liverpool Bay on 16 and 20 February 1974. The other sightings came from Hilbre or Red Rocks (six records), the mouth of the Mersey (three), and two inland at Moore and Rostherne. Most sightings were of single birds, but once two were together and on two occasions the observer reported three birds: all of these multiple sightings were from Hilbre or Red Rocks, emphasising the importance of the mouth of the Dee as the main area frequented by this rare winter visitor.

The unusual nature of winter records was emphasised in the BTO Winter Atlas (1981/ 82 to 1983/ 84), when Arctic Skuas were found in only 44 10-km squares, several of them in the exceptional westerly gales of November 1982 that brought Cheshire and Wirral its record numbers. In those three years there were only 11, 8 and 4 records anywhere in the country in the months of December, January and February.