December 1954 – vol. 47, issue 12–422 T H E present paper is based on reports published by the four southwestern Bird-Observatories, Bardsey, Great Saltee, Lundy, and Skokholm. These reports are restricted to a general description of the main movements of each species, and the field-seasons vary in length between four and ten months of the year, so that only a broad comparison for limited periods is possible. The actual fieldseasons i... This article is only available to registered users.To read more, please log in or purchase a subscription.