Counting Seabirds at Sea from Ships: A Review of Methods Employed and a Suggestion for a Standardized Approach

--We review the methods used to study seabirds at sea from ships, discuss the problems posed in making reliable observations in relation to the design of research programs, and describe a method currently in use around the seas of Great Britain. We suggest a framework for future studies, incorporating features likely to stabilize bias. The key items in this recommendation are (1) the use of a band transect in order to provide density estimates, and (2) a method to correct for movement of flying birds in the band transect in order to minimize bias caused by such movement. Received 13 October 1982, accepted 5 December 1983. THE recent upsurge in studies of seabirds at sea has often been in response to the need to assess the potential impact of hydrocarbon developments offshore. Marine biologists are also realizing that seabirds play an important part in marine ecosystems, and seabird ornithologists are becoming aware of the fact that studies of seabird biology must extend beyond the colonies. Attempts to produce systematic ounts of seabirds at sea have resulted in almost as many methods as there have been studies. In this paper, we review these methods and discuss associated problems. If studies are to become more comparable, the methods used will have to become more standardized; therefore, we suggest an approach that may help achieve this aim. DEVELOPMENT OF QUANTITATIVE SURVEYS