Fig. 2. Metabolic rate (MR in W) and daily energy expenditure (DEE in kJ) during a 24 h period declined with increasing chaff/seed ratio (F_1,85=22.7, P<0.001) and temperature (F_1,85=3057, P<0.001), and increased with body mass (F_1,93=9.77, P<0.005). The interaction between chaff/seed ratio and ambient temperature was not significant (F_1,84=1.41, P=0.24). Also plotted is the metabolizable energy intake as measured by Lemon (1993) in zebra finches on similar chaff/seed regimes. The plotted data are not corrected for body mass.