Thermoregulation in four species of arctic seabirds

Abstract

Thermoregulation was studied in four species of seabirds in Ny-Alesund, Svalbard. The major findings of the study are: 1. Resting metabolic rates (RMR) were 1.64, 1.00, 1.59 and 1.11 ml O2/g·h, thermal conductance (TC) 0.0466, 0.0336, 0.0475 and 0.0282 ml O2/g·h·°C and body temperature (Tb) 40.2, 38.7, 39.9 and 39.6°C, in Kittiwakes, Fulmars, Black and Brunnich's Guillemots, respectively. 2. RMR values from all four species were above predicted values based on equations from Lasiewski and Dawson (1967), Aschoff and Pohl (1970) and Ellis (1984). In Kittiwakes the measured RMR values were 183%, 158% and 156% of predicted values while in Fulmars only 131%, 113% and 112%. 3. Thermal conductance was lower, i.e. insulation better, in Fulmars and Brunnich's Guillemots compared to Kittiwakes and Black Guillemots. TC values obtained in this study were different from values predicted from equations of Herreid and Kessel (1967) and Aschoff (1981). While Herreid and Kessel's values were somewhat elevated, Aschoff's equation gave values below our measurements. 4. Low ambient temperatures and the birds' activity level are suggested as the major reason for high RMR in Kittiwakes, Black and Brunnich's Guillemots. 5. The RMR values measured in Fulmars did not differ from those of Procellariiformes studied in sub-Antarctica. It is suggested that the lower metabolic rate and body temperature enable Fulmars to survive extended periods of fasting.