Fig. 1. Heat transfer by convection (red symbols), evaporation (dark blue symbols) and radiation (pink symbols), and metabolic power (P_met,heat, black symbols) of four starlings during flight in a wind tunnel at speeds (V) between 6 and 14 m s^–1. Different symbols show data from different birds (diamonds, bird 2; triangles, bird 12; circles, bird 15; squares, bird 19; N=5 speeds for each bird). The line shows the regression, P_met,heat=0.57±0.08V+5.01±0.79, r²_adj=0.74, P<0.001, N=20.