Investigation of average daily water consumption and its impact on weight gain in captive common buzzards (<i>Buteo buteo</i>) in Greece

Abstract

This investigation was to find out whether captive common buzzards need additional drinking water to complement the water they obtain from their pre-slaughtered meat meals and to investigate their average daily water requirements. Twenty five (25) common buzzards were studied at the wildlife hospital and rehabilitation centre, Aegina, Greece with weight ranging between 498.4g and 911g. Large quantity of potable water was measured equally into same size ceramic bowls and served each bird under study in separate individual paper boxes. At the end of 24 hours, the left over water was carefully brought out and re-measured to determine the quantity the birds have consumed. A control was set with a ceramic bowl with same quantity of water put in a paper box without a bird to determine the quantity of water lost to the atmosphere through evaporation on each day of the experiment. The water lost from the control on a daily basis was corrected in order to determine the quantity the common buzzards consumed daily. The weight of the studied buzzards were carefully taken and recorded 6 times each during the study period with W₁ and W₆ as entry and exit weights respectively. The mean of W₁-W₆ was used for the computation of the average percentage live body weight of the buzzards. The investigation revealed that captive common buzzards took water every day and the average daily water consumption of 724.9g buzzard was 31.4cc or 4.3% of its live body weight. The investigation further shows that the average water lost by evaporation daily (10.7cc) and that consumed by each buzzard daily (31.4cc) add up to 5.8%, equivalent of the average live body weight of the studied captive common buzzards which was 724.9g. The regression coefficient indicated that weight gain/ loss = 0.942 + 1.795 H₂O. This implies that a unit increase in the average quantity of water consumed resulted in a corresponding increase of 1.795 body weight gain by the captive common buzzards.

Keywords: Daily water consumption, Weight Gain, Captive common buzzards.