Larus michahellis – Gwylan Goesfelen – Rare visitor
Rightly or wrongly, we have anticipated that this ‘race of Herring Gull’ will be afforded specific status in the future. The Yellow-legged Gull has a mantle colour that is much darker than a Herring Gull’s and it remains white-headed in winter. Its breeding range is from Biscay to central Asia and in south-west France it overlaps with the Herring Gull subspecies argenteus without interbreeding (Yesou 1991).
It has been detected in southern Britain with increasing frequency in recent years, including the following Pembrokeshire records: in 1985, one at Llanstadwell from 6 February to 11 April (G.H. Rees) and two on 18 February, singles at Marloes Mere on 3 March and 26 December, at the Gann on 3 March, at Wiseman’s Bridge from 27 February to 13 March and at Fishguard Harbour on 6 January; in 1986, one at Llanstadwell on 14 February and at the Gann on 15 February; in 1987, single, but different, birds at Llanstadwell on 17 and 31 March.
Great care is needed when identifying these birds as hybrids between Lesser Black-backed and Herring Gulls persist in the Pembrokeshire population, following cross-fostering experiments on the islands. The hybrids characteristically have more elongated primaries, show a mixture of rather washed out yellow or pink legs, sometimes yellow and pink, and in winter have streaked heads.