Population Changes in the Mountain Hare, Lepus timidus L.

Abstract

A population of mountain hares on about 200 ha of moorland in Banffshire has been studied since 1955 by capturing and recapturing marked animals and by other methods. An index of trapping showed a population increase from 1956 to 1958, followed by a decline in 1959 and a period of scarcity lasting until the end of 1962. Counts in parts of the study area confirmed the timing and extent of these changes. Mountain hares appeared to be sedentary and population changes due to immigration and emigration were unlikely. Hares were found dead most frequently in the early months of 1958 and 1959. Carcases showed heavy infestations of internal parasites, but hares killed in other years and in good condition showed slight to severe infestations. Breeding success was high in the years when thepopulation was declining or low. Both adult and juvenile mortality were high throughout peak numbers and the decline. Annual adult mortality was estimated to be about 79%, and juvenile mortality 76% among leverets aged from about 2 months upwards. Food shortage and disease (linked with heather damage due to weather) may have affected a high population at a critical season in 1958 and 1959.