Water Restriction Effects on Northern Bobwhite Reproduction

We compared the reproductive function of domestic and wild-caught northern bobwhites (Colinus virginianus) receiving ad libitum water with those receiving the minimum required for mass stasis under simulated spring and summer conditions. Relative gonad size, expressed as a percentage of body mass, was similar (P≥0.10) between domestic and wild-caught birds. Males appeared to be robust to water availability as restriction did not affect mean testis mass (P≥0.14), and testis mass varied independently of daily water intake (r≤0.37, P≤0.09). Females on restricted intake of water had lower (P=0.0001) ovary and oviduct mass than females receiving ad libitum rations in both seasons; mass of these organs varied directly with daily intake (r≥0.68, P≤0.0009). Reproductive organs of water-restricted hens failed to recrudesce in spring and failed to maintain function in summer. The results were consistent with an hypothesis that water deprivation, largely through effects on females, could contribute to reproductive failure of bobwhites during drought