Estimating Lipid Content of Sandhill Cranes from Anatomical Measurements

Abstract

mate total lipid reserves in sandhill cranes (Grus canadensis) from mid-continental North America. Lipid content alone (Evans and Smith 1975, Woodall 1978, Bailey 1979) and lipid content with protein reserves (Wishart 1979) have been used as indicators of physiological condition. Positive relationships have been found between the physiological condition of common eiders (Somateria mollissima) during winter (Milne 1976) and geese in spring (Maclnnes et al. 1974, Ankney and Maclnnes 1978) and subsequent clutch size. Also, a positive relationship was detected between condition of mallards (Anas platyrhynchos) and wintering food supplies (Owen and Cook 1977). Lower body weights of Canada geese (Branta canadensis) during winter may be caused by decreased winter food supplies (Hanson 1962, Raveling 1968). Knowledge of the physiology and condition of a species is essential to the understanding of habitat requirements (Fredrickson and Drobney 1977). The ability to assess the condition of sandhill cranes provides a management technique to evaluate the physiological response of a species to dynamic environmental conditions and to quantify management activities related to refuging species. Approximately 10,000 cranes are harvested annually in mid-continental North America (Lewis 1977). Methods are needed to allow periodic evaluation of the condition of sandhill cranes, particularly because lipid levels of cranes have been shown to vary annually during comparable periods in the annual cycle (Iverson 1981).