Fig. 4. Whole-body water vapour diffusion resistance r_v as a function of air temperature in cool- and heat-acclimated western white-winged doves Zenaida asiatica mearnsii. The solid lines are linear regressions fitted to the data. The regression for the heat-acclimated doves (lower line) is r_v=536.59-11.01T_a (r²=0.634) and that for the cool-acclimated doves (upper line) is r_v=529.06-9.22T_a (r²=0.395). The slopes of these regressions did not differ significantly.