The United Kingdom's largest bird of prey, the white-tailed eagle is sometimes known as the 'sea eagle', and preys on fish, mammals and small birds. It was persecuted to extinction in the United Kingfom, but was reintroduced from Norway during the 1970s. White-tailed eagles mate for life and breed in the same territory each year - this territory may even be used by successive generations for many more years to come.