A new search behaviour: porcupines scout for winter habitat during summer

Traditional conceptual models of movement assume that animals have 'perfect knowledge' of their environments. Although strong selective pressure may optimize animals' abilities to select favourable habitat components, few, if any, are born with an innate understanding of their environments. That is, individuals need to learn about the distributions and qualities of resources available to them, and this is particularly true for long-lived animals that must cope with dynamic environments over the courses of their lives. Members of many species passively acquire information about their environments while performing other essential activities, such as acquiring food, maintaining territories or searching for mates. But growing evidence suggests that animals may move deliberately for the express purpose of acquiring information. One such behaviour that may benefit animals particularly is to scout for winter resources (i.e. a limiting period) during summer (i.e. a time of abundance) when movements are less costly. Here, we investigate a population of North American porcupines, Erethizon dorsatum, to test whether they display this behaviour. We compared summer and winter habitat use by porcupines using GPS data and radiotelemetry. We also monitored seasonal selection of winter habitat with the use of trail cameras. We examined selection of nutritional and structural characteristics to identify potential drivers of scouting behaviour. We found that porcupines randomly sampled winter habitat during summer and returned in winter to locations with greater structural complexity but not higher nutritional quality. This study provides evidence of animals deliberately moving during summer to gain information about winter resources. More broadly, we suggest that scouting may be a search behaviour that individuals use to inform selection of resources in limiting seasons. Future research should test for similar seasonal movement characteristics across taxonomic groups and ecoregions.