The barnacle goose is a medium-sized goose, 55–70 cm (22–28 in) long, with a white face and black head, neck, and upper breast. Its belly is also white.
About 3,000 Barnacle Geese arrive in October to spend the winter in North Sligo. The animals breed in Greenland in the summer and spend the winter in Ireland, and the Ballygilgan Nature Reserve is one of the best sites in Ireland for seeing them.
In North Sligo, geese graze in Lissadell – Maugherow area from october until April, forming large skeins (V shape) of geese at dawn and dusk, when they fly every day to their night quarters in the island of Inishmurray. ...one of the most spectacular sights imaginable on a fine winter's evening.