Larus hyperboreus – GWYLAN Y GOGLEDD – Irregular winter visitor.
The Glaucous Gull breeds along the north coasts of Canada and Eurasia, and their associated islands. Most move south in the winter, though often still spending the season in frozen areas.
They are now seen regularly in Pembrokeshire in winter, often staying well into the spring. Small numbers are involved, sometimes none. Large movements are thought to be associated with colder weather further north, or rough weather at sea. However, not all cold winters bring birds this far south – there were none in 2010, and the influx in 2014 was during a relatively mild winter.
Once here, many birds stay around for a while, sometimes a few months, visiting a number of sites and sometimes making it difficult to determine exactly how many are present.
In early 2017 a colour-ringed first-winter bird turned up at Holyhead in Anglesey. It has been ringed as a chick on Svalbard, off the north coast of Norway, the previous year. This is so far the only indication of the origins of birds coming to Wales, but it does not mean that others don’t come from Iceland or Greenland.
Other sites have been used, eg Llanstadwell, Fishguard Harbour, Penberi Reservoir, while some birds have been recorded flying past St Govan’s Head and through Ramsey Sound.