Helicopter parenting: local-scale environment determines hiding and supervision in neonatal ungulates

Abstract

Ungulate species are classified as ‘hiders’ rather than ‘followers’ when neonates tend to remain separated from their mother and hidden within vegetation during the early postpartum period. Among species, hiding is associated with the availability of cover habitat; however, our understanding of these behaviours often has been limited to relatively coarse and infrequent observations. We leveraged modern technologies, including GPS collars affixed to neonates, LiDAR, fine-scaled encounter risk with predators, accelerometers and multiscale temperature readings, to complement these observations in evaluating how predation risk, thermoregulation and nutritional attributes of habitat contribute to hiding behaviour and its consequences for survival in mule deer, Odocoileus hemionus. Hiding decisions by mule deer were nuanced and counter to prevailing notions that suggest hiding is associated with increasing availability of cover. In support of the risk hypothesis, mule deer were most likely to hide in areas where vegetation height was low and encounter risk with predators was high, and behavioural shifts were prominent relative to variation in time of day, with hiding behaviour increasing at night during periods of predator activity. Nutrition and thermoregulatory hypotheses were supported in that hiding was more likely and neonate and mother were in closer proximity in areas with greater resource availability, and neonates adjusted hiding behaviour to minimize thermoregulatory costs. Variation in hiding indicated the importance of activity and interaction with the mother for neonate survival. Broad-scale habitat patterns have proven useful for defining hiding behaviour across species and may play an important role in setting the bounds that define individual variation; however, we encourage considering local conditions as drivers of hiding and following behaviour in ungulates. Together, patterns across multiple scales are more likely to describe the nature of neonate behaviour, relative to considerations at one scale alone.