Water Economy of the White-Crowned Sparrow and Its Use of Saline Water

Abstract

range are the arid portions of southern California and adjacent regions (Grinnell and Miller, 1944). It is one of the most conspicuous winter-visitant sparrows in Joshua Tree National Monument, located in the transition between the Mojave Desert and the Colorado Desert in California (Miller and Stebbins, 1964). In addition Banks (1963) reports the occurrence of large flocks of White-crowned Sparrows (not subspecifically designated) on several of the desert islands in the Gulf of California during March and April 1962. The physiology of photoperiodically influenced phenomena in the White-crowned Sparrow has been intensively investigated by Farner and his colleagues (for example, Farner, 1964); King (1964) has recently reported on its metabolism and body temperature, and Morton (1965) has analyzed its food intake and feeding periodicity. In spite of these many investigations and in spite of its frequent habitation of xeric situations in the winter, information on the water relations of the Whitecrowned Sparrow is fragmentary. This investigation undertakes to examine the water economy of the Whitecrowned Sparrow in order to expand our knowledge of its general biology. Specifically, the study attempts to assess the ability of the White-crowned Sparrow to maintain water balance on the desert and to utilize saline water that may be present in desert springs and as sea water in portions of its winter range.