BASAL METABOLIC RATES OF NORTH-ATLANTIC SEABIRDS

Basal metabolic rates (BMR) were measured for 11 species of North Atla ntic seabirds, ranging in size from the Kittiwake Rissa tridactyla to the Gannet Sula bassana. BMRs for all species were higher than those p redicted from the allometric equations of Lasiewski and Dawson (1967), Aschoff and Pohl (1970) and Ellis (1984), The equations of Ellis (198 4), incorporating a latitude correction, and of Bennett and Harvey (19 87), involving deviations by seabird families from a general avian tre nd line, gave predictions for BMR which were closer to, but respective ly lower and higher than, those observed in this study, BMR for seabir ds in Scotland (55-60 degrees N) is described by the equation: BMR (kJ /d) = 2.30W(0.774), The principal sources of variability in BMR amongs t seabirds and the selective forces shaping the differences between se abirds and most other birds with lower BMRs remain unclear but deserve further study.