1. Benn, S., Tasker, M. L. & Reid, A., 1987. Changes in numbers of cliff-breeding seabirds in Orkney, 1976–1985. — Seabird10, 51–57.
2. Birkhead, T. R., 1977. Adaptive significance of the nestling pΘriod of guillemotsUria aalge.—Ibis119, 544–549.
3. Birkhead, T. R., 1978. Attendance patterns of guillemotsUria aalge at breeding colonies on Skomer Island.—Ibis120, 219–229.
4. Blake, B. F., Tasker, M. L., Jones, P. H., Dixon, T. J., Mitchell, R. & Langslow, D. R., 1984. Seabird distribution in the North Sea. Nature Conservancy Council, Huntingdon, 336 pp.
5. Bradstreet, M. S. W. & Brown, R. G. B., 1985. In: The Atlantic Alcidae. Ed. by D. N. Nettleship & T. R. Birkhead. Acad. Press, London, 574 pp.