Fig. 3. Cloacal fluid (CF) osmolality (note the logarithmic scale) as a function of water flux. (A) CF osmolality increased with increasing dietary sucrose concentration. Sunbirds were fed sucrose solutions of varying concentrations (0.07 to 2.5 mol l^–1), with (solid bars) or without (open bars) supplementary drinking water. Values are means ± 1 S.D. (N=7). (B) CF osmolality was inversely correlated with CF volume (both logarithmic scales). Values are individual data (N=7) for the 14 diet trials with (solid circles), or without (open diamonds), supplementary water; the regression line is fitted to data from all diet trials (osmolality=253.5[CF volume+1]^–1.054). The volume of CF excreted per day is given as log(ml+1) since the log of values <1 yields negative values.

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