|Scientific name:||Uria aalge|
Resident, though occur inshore/ land during the breeding season, March/April to August/September.
The commonest species of Auk in Ireland, a highly marine species which are only found on land in the breeding season. A dark brown and white seabird, brown above and white below, with a distinct breeding plumage. In the breeding season head and neck completely dark brown, in the winter white on front of the neck and face. At a distance can be confused with Razorbill. Guillemot has a longer body, browner upperparts with less white on the side of the body and a lighter bill. Shows a darker 'armpit' than Razorbill. Seen flying in lines close to the sea with Razorbills.
Vocal in colonies with birds giving repeated nasal notes and prolonged bellowing. The young on the sea also give a high-pitched call after leaving the breeding colony.
Mainly small fish, some invertebrates, caught by surface diving.
Comes ashore to nest from May onwards, colonies deserted by the first week in August. Nests on cliff ledges, often in large colonies, defends the smallest nest territory, sometimes only 5cm square. Restricted to cliffs with suitable ledges. Lays egg directly on to rock.
Winters at sea. Some Irish birds are believed to winter near their breeding sites.
Breeding seabirds are monitored through surveys carried out every 15-20 years, the last was Seabird 2000, which was undertaken between 1998 & 2002.
Coastal breeding bird. With over 21,000 birds, Great Saltee island, off County Wexford holds one of the largest populations. The Cliffs of Moher, in Co. Clare hold over 19,000 birds. Other places include Loop Head in Co. Clare, with over 5,000 birds, and Horn Head, in County Donegal with over 6,500 birds. Numerous smaller colonies occur around the Ireland, especially on the west coast. Can also be seen on Irelands Eye and Howth Head, County Dublin.
In Winter, widespread out to sea around all coasts.