Demographic Factors Affecting Management of Sandhill Cranes

Practices for management of sandhill cranes (Grus canadensis) are affected by the present classification which indicates five subspecies. Investigation in 1961, 1962, and 1963 of the taxonomic status of migrant sandhill cranes at Last Mountain Lake, Saskatchewan, indicated that color of primary feather shafts is not a reliable taxonomic character. Significant differences between adult males and females in weights, lengths of bill, bill from tip to posterior of nostril, tarsus, mid-toe, and total length require that sexes be distinguished when these characters are used for taxonomic purposes, but broad overlap precludes their use for determining sex. Observed frequencies of weights and lengths of tarsus, bill, and bill from tip to posterior of nostril conformed to a normal distribution, but, using the existing criteria, 75 percent of adult males from Last Mountain Lake could not be classified as one of the reported subspecies. It is concluded that use of the existing criteria to differentiate the greater, the lesser, and the Canada sandhill cranes is unwarranted. There were few sandhill crane hunters during the 1964 and 1965 seasons in Canada. Most were seeking recreation; hunting success was low. Because recruitment rate of cranes is low, effective management requires a high degree of confidence in data on crane populations.