Brood patch temperature during provocation of incubating common eiders in Ny-Ålesund, Svalbard

Abstract

In this short note we describe the behaviour and body temperature changes of three incubating female common eiders (Somateria mollissima) during provocation made by humans approaching the nest. The study site was near the settlement of Ny-Ålesund, Svalbard. Temperature transmitters were implanted subcutaneously at the brood patch and data recorded using a VHF receiver. We found that the female eiders in the experiment exhibited a passive defence response ("freezing"), accompanied by a significant drop in brood patch temperature (0.6 °C) during provocation; this temperature drop lasted for 5 minutes. These results accord with other studies of the physiological changes which accompany the passive defence response in birds and other animals.