Parturition Effects on Sociality and Dynamic Interactions of Female White-tailed Deer

Abstract

Abstract Background Female white-tailed deer (Odocoileus virginianus) typically form matriarchal social groups throughout much of the year; however, little research has examined the effect of parturition on sociality. We used measures of dynamic interaction, a function of travel direction and displacement, to examine social interactions between adult females before and after parturition. We monitored parturient, free-ranging individuals on a 126-ha property using vaginal implant transmitters linked to GPS collars during a 2-month period surrounding peak parturition (1 May–30 June 2016). We calculated local dynamic interaction (di; cohesiveness of movement for each time step) and global dynamic interaction (DI; cohesiveness of movement throughout the study period) metrics for all female pairs with overlapping 95% kernel density home range estimates (n = 29 interaction pairings). Results Global DI was correlated positively with home range overlap (%). Mean local di values indicated moderate social cohesion within the population prior to parturition. Following parturition, mean local di values declined below zero suggesting avoidance among female pairs with overlapping ranges. Mean local di began to increase approximately 15 days postpartum but did not return to prepartum levels during our study period (~ 25 days postpartum). Conclusions The changes in female social dynamics following parturition are likely a trade-off among several factors such as neonate mobility, predator avoidance, and nutritional demands. However, the trends we observed are to be expected given the life history of female deer around parturition in which sociality declines around parturition and then returns gradually to pre-parturition levels.