Some correlates of interaction rates in natural populations of woodchucks [Quelques corrélats sur les taux d'interactions dans les populations naturelles de marmottes].

Résumé

Seven aggregates, each a complex of 5 neighboring woodchlucks, were observed for 3 to 4 weeks each between May 1959 and September l960. These aggregates were assumed to be representative of the seasons and natural populations in which they were observed. A total of 11,648 min of movenent and behavioral activity were obtained. After field observation, each aggregate was subjected to competitive dominance tests to obtain relative rank status for the members. Aggressive interaction rates for the various aggregates were found to be more dependent upon seasonal changes in aggressiveness than upon density. Three of the 4 aggregates observed during the April to early June period when aggressiveness was high were characterized by generally lower densities, high interaction rates, and high levels of down-alert activity. The level of down-alert activity appeared to be related to relative rank in 2 of the 4 groups. Three groups observed later in the year, when aggressiveness was lower, showed low interaction rates, low levels of down-alert activity, and no correlations with rank, even though densities of 2 of the 3 groups were the highest investigated. Home range and adrenal weight data showed suggestive relationships with interaction rate.