Fig. 3. Water flux in sunbirds (filled circles) estimated from fractional water turnover rate (K_³H) and total body water (TBW) measurements ranged from 112.97 µl h^-1 to 463.83 µl h^-1 and increased linearly with water intake rate (r²=0.89, F_1,29=237.29, P<0.0001). The slope of this relationship was significantly less than 1.0 (slope ± S.E.M.=0.42±0.03, t=22.8, d.f.=33, P<0.001), and significantly lower than that of the same relationship in broad-tailed hummingbirds (unfilled diamonds; slope ± S.E.m.=0.88±0.05, ANCOVA_slopes F_1,35=27.8, P<0.0001; data for hummingbirds from McWhorter and Martínez del Rio, 1999).