Comparing Survival and Movements of Non‐Urban and Urban Translocated Mule Deer

Abstract

In many parts of North America, deer (Odocoileus spp.) have adapted to live in urban areas and are a source of negative human-wildlife interactions. Management strategies such as culling, immunocontraceptives, sterilization, and translocation have been implemented to manage urban deer populations. In the East Kootenay region of southern British Columbia, urban mule deer (Odocoileus hemionus) populations have been increasing, whereas non-urban mule deer populations have decreased. In 2014 a non-urban mule deer research project began in the area and in 2016 an urban deer translocation trial was approved in the same region. We fit 121 non-urban deer with global positioning system (GPS)-collars and translocated 135 urban mule deer to non-urban areas, of which 57 were fit with GPS-collars. We tested if annual survival between urban translocated (i.e., translocated) and non-urban deer differed, and if translocated deer survival increased in subsequent years after translocation. We also determined if age, body condition, release site, capture area and distance between capture and release sites affected translocated deer survival. We evaluated if translocated deer exhibited different movement behaviors than non-urban deer by comparing probability of migration, maximum net displacement, home range size, and probability of crossing a paved road. Finally, during our study we observed some translocated deer return to a municipal area after translocation and assessed if any covariates such as age, release site, or capture city could help predict this behavior. Annual survival of translocated deer was 0.48 and was significantly lower than survival of non-urban deer, which was 0.77. We observed 20 of 57 collared translocated deer return to a town after translocation. Translocated deer had larger net displacements and larger seasonal home range sizes than non-urban deer. Non-urban deer were more likely to migrate than translocated deer and crossed fewer paved roads than translocated deer. The management effectiveness of translocation to reduce urban deer densities is mixed because annual survival of translocated deer may be lower than may be acceptable to some stakeholders. Additionally, some translocated deer returned to an urban area, and the large distances traveled by deer after translocation may unintentionally spread disease.

Outcomes associated with translocation of mule deer (Odocoileus hemionus): Influence of age, release timing, and year on survival

“…Survival rates for translocated mule deer in year one (0.51 and 0.53) were lower than those of resident deer (0.83). These lower rates during the initial year following release, however, are similar to those reported for black-tailed or mule deer translocated in other areas using a variety of methods (O'Bryan and McCullough, 1985;Martinez-Garcia, 2009;Cain et al, 2018;Wright et al, 2020). During the second year, survival rates for translocated mule deer were higher and not different from resident deer (Figure 2) suggesting that survival challenges related to translocation were transitory and dissipated by the end of the initial year.…”

“…This finding supports our prediction that translocated deer would experience lower survival rates than resident deer during the first year after release, but higher rates of survival (when compared to survival for translocated deer in year 1) during the second year once acclimated to release areas. While low survival of ungulates is a common observance following translocation (Beringer et al, 2002;Frair et al, 2007), there are few translocation studies that have documented survival for multiple years following release (Haydon et al, 2008;McIntosh et al, 2014;Wright et al, 2020). These data reinforce the need to monitor translocated animals for multiple years following release.…”

“…Despite decades of intensive management in western North America, outcomes associated with translocation of mule deer (Odocoileus hemionus) have only recently been documented. Typical results show increased movements and reduced survival for translocated animals in the initial year following release (Wakeling, 2003;Cain et al, 2018;Howard, 2018;Smedley et al, 2019;Wright et al, 2020). Annual survival of translocated mule deer during the initial year following release, for example, ranged from 15 to 79 percent which is low for this species (Wakeling, 2003;Cain et al, 2018;Wright et al, 2020).…”

“…Typical results show increased movements and reduced survival for translocated animals in the initial year following release (Wakeling, 2003;Cain et al, 2018;Howard, 2018;Smedley et al, 2019;Wright et al, 2020). Annual survival of translocated mule deer during the initial year following release, for example, ranged from 15 to 79 percent which is low for this species (Wakeling, 2003;Cain et al, 2018;Wright et al, 2020). Most of these efforts, however, did not involve monitoring of translocated mule deer during their second year following release or comparison with resident deer in the release area.…”

The effects of maternal penning on the movement ecology of mountain caribou

“…Studies on animals encountering novel terrain reveal complex movement and navigation processes. For example, some species retain their aversion to people/disturbance following translocation (Ford & Fahrig, 2008), while other translocated species may travel farther, encounter more disturbances, and experience greater risks than nontranslocated conspecifics (Ishii et al ., 2019; Wright et al ., 2020). Studies have shown that there can be an exploratory phase when an animal encounters a new environment before ‘settling’ (Fryxell et al ., 2008), akin to home range formation following natal dispersal (Fattebert et al ., 2015).…”