Fig. 5. The effect of protein intake on plasma uric acid. For a given protein intake, the plasma concentration of uric acid was significantly higher in yellow-vented bulbuls (open circles) than in Tristram's grackles (closed circles). Plasma uric acid concentration was positively correlated with protein intake in Tristram's grackles, (y=0.0004x+1.07, F_1,6=11.22, r²=0.65, P=0.015), but not in yellow-vented bulbuls (F_1,5=0.07, P=0.8). We standardized protein intake by mass^0.75 to place both species along an axis of similar magnitude.