Plumage temperatures of dippers Cinclus cinclus on the roost and in the hand: Implications for handling small passerines

The outer breast plumage temperature of Dippers Cinclus cinclus roosting beneath river bridges was measured using an infra red thermometer over the environmental temperature range –0.8 to +10.9°C. Plumage temperature was close to, and directly related to, the temperature of the birds’ surroundings, but significantly higher (?T = 2.87°C), suggesting slight heat loss across the plumage to the environment. Plumage temperatures were also measured in Dippers held in the hand; they were much elevated over environmental temperatures (?T = 17–18°C at 0°C), indicating substantial heat loss during handling.