They nest in large groups on cliff ledges and small islands on the coasts of [[Europe]] and [[Canada]], although it is most common in the [[British Isles]]. They spend the winter at sea as far south as [[Mexico]], the [[Caribbean]] and [[Africa]]. They are also occasional visitors to the [[Great Lakes]]. | They nest in large groups on cliff ledges and small islands on the coasts of [[Europe]] and [[Canada]], although it is most common in the [[British Isles]]. They spend the winter at sea as far south as [[Mexico]], the [[Caribbean]] and [[Africa]]. They are also occasional visitors to the [[Great Lakes]]. |