Water Turnover and Estimated Food-Consumption in 3 Species of Fairy-Wren (Malurus Spp)

Abstract

Water influx rates and estimated food consumption rates were determined for adults, juveniles and nestlings of three co-existing species of fairy-wrens: superb (Malurus cyaneus), variegated (M. lamberti) and white-winged (M. leucopterus). There were no significant interspecific differences with respect to water influxes of either juveniles or adults, but variation within species was large. Adults and juveniles had higher water influx values and daily food requirements than nestlings. M. cyaneus nestlings had higher mass-specific water influxes and food intakes than both M. leucopterus and M, lamberti, but the latter two did not differ in these parameters. The higher mortality of M. cyaneus and the requirement for drinking water during hot, dry conditions indicate that the inland distribution and abundance of this species are more constrained by climatic conditions than are populations of M. lamberti and M. leucopterus.