DIURNAL TIME BUDGET OF THE MOUFLON (OVIS MUSIMON) ON THE KERGUELEN ARCHIPELAGO - INFLUENCE OF FOOD RESOURCES, AGE, AND SEX

The population of introduced mouflons on the Kerguelen subantarctic ar chipelago (Indian Ocean) is characterized by a demographic cycle marke d by rapid variations in density. The diurnal time budgets of the diff erent age-sex classes were compared between two consecutive summers se parated by a winter with a massive die-off. Following the drastic redu ction in population density between 1994 (100-110 individuals/km(2)) a nd 1995 (40-50 individuals/km(2)), mouflons spent less time foraging, while the time devoted to rest did not differ significantly. This diff erence is explained by an increase in food availability that allowed t he animals to become satiated more rapidly. Although the time spent re sting did not differ between the two summers, shorter foraging phases may explain the occurrence of a more polymodal rhythm for these two ac tivities when range conditions improved. Our results indicate that eve n during the summer period of relative food abundance, the diurnal tim e budget of mouflons is strongly affected by population density. At hi gh population densities, animals may find it more difficult to restore their body condition and reserves, even in summer. This could have co ntributed to the high mortality rate observed the following winter.