The great black-backed gull is the largest of the Irish gulls, and is much bigger than the black-headed gull. The adult birds have a black back and wings with white wing tips. They have flesh-pink legs and a heavy yellow beak with a red spot. The plumage of juvenile and immature great black-backed gulls initially has a complex pattern of black/brown/white showing more contrast than on other young large gulls. As it matures, the back turns black first (giving a ‘saddle-back’ appearance). In flight, you can see their black back; and their broad black wings with a white trailing/leading edge and their white wing tips are also visible. Great black-backed gulls have a strong agile flight. When flying, the young birds show their pale inner primaries and their indistinct dark tail band is visible in flight. Their voice features deep calls, including a short ouawk. Tip of the Week: Gulls are found everywhere in Ireland, from the inland-nesting black-headed gull to the great black-backed gull found breeding mainly on cliffs and offshore islands. They have adapted to living with humans. Two examples of this are the noisy clouds of scavenging gulls following a trawler into port and the trail of gulls following the plough in search of insects and worms. Terns come here in their thousands each summer from their wintering grounds in Africa and beyond. The roseate tern, which is the rarest breeding tern in Europe, has one of its largest colonies on the BirdWatch Ireland/DOE-managed island of Rockabill off the north Dublin coast. Skuas are mainly non-breeding summer visitors and are often referred to as sea-hawks or pirates. They chase other seabirds, usually gulls and terns, until they surrender the food they are carrying. Jim Wilson is a wildlife writer, broadcaster, tour leader, and former chairman of BirdWatch Ireland. He has been involved in the study and conservation of birds in Ireland for more than 45 years, contributing to several major surveys and international projects. Mark Carmody is an award-winning wildlife photographer, has a PhD in biochemistry and works as a European patent attorney.