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

In this short note we describe the behaviour and body temperature changes o f three incubating female common elders (Somateria mollissima) during provo cation made by humans approaching the nest. The study site was near the set tlement of Ny-Alesund, Svalbard. Temperature transmitters were implanted su bcutaneously at the brood patch and data recorded using a VHF receiver. We found that the female elders in the experiment exhibited a passive defence response ("freezing"), accompanied by a significant drop in brood patch tem perature (0.6 degreesC) during provocation; this temperature drop lasted fo r 5 minutes. These results accord with other studies of the physiological c hanges which accompany the passive defence response in birds and other anim als.