Juvenile Mediterranean Gull (left) with Black-headed Gull, Black Rock, 17th August 2017 (David O'Connor).
Numbers of 'Med' Gulls continue to rise in Kerry, with record numbers seen in the mid-summer period though, as juvenile birds disperse away quickly from their breeding colonies, their appearance at that time doesn't necessarily mean they have bred nearby.
Nesting Mediterranean Gulls have been spreading north and west in Europe in the last decade, first nesting in Ireland at Lady's Island Lake in Wexford in 1995, and nesting has been regular ever since. 72 pairs bred there in 2016 (see the National Park and Wildlife Report HERE) while in Northern Ireland, seven pairs nested at Larne Lough and two nested at the RSPB reserve in Belfast Harbour in 2017 (see HERE). Fledged juveniles had left the nest site in Wexford by 11th July.
A common characteristic of colonising Mediterranean Gulls is that they have a strong preference to nest within colonies of Black-headed Gulls (often with Sandwich Terns present too) for added protection from predators. Unfortunately, the chances of them colonising Kerry are now considerably lessened by the recent demise of Kerry's only Black-headed Gull colony at Kilmacalogue Harbour in Kenmare Bay.