I have looked at some of the colour ringing/ringing details received over the last few years for Med gulls and, so far, we have details of birds ringed either as young or as adults at breeding colonies in the Netherlands, Germany, Belgium, France, Poland and Hungary which were later seen in the county. The location of ringed black-headed gulls seen in the county seems to be slightly further east with records from Norway, Estonia, Lithuania with one from Belgium. In Birds of Wales, Hume (1976)states that at Blackpill, Glamorgan wintering med. gulls departed by end April, in April and May there was an influx of 1st year birds followed by a fresh arrival of adults and 2nd year birds from late June.On the Dyfi in most years there is a large influx of black-headed gulls from July onwards (certainly too many to be local birds) and it is interesting to speculate that these may have come from the Baltic states breeding colonies (and may have caught up the gull-billed tern seen in 2007, the closest breeding colonies for this species being in the Baltic sea region). Strangely though, Med. gulls seem to disdain the Dyfi area at this time of year with nowhere near the numbers recorded at favoured spots further south though there was a fine adult in breeding plumage with the black-headed gulls today and yesterday.
Russell Jones
Warden
Ynys-hir RSPB reserve
Gwarchodfa natur Ynys-hir