Dynamic winter weather moderates movement and resource selection of wild turkeys at high‐latitude range limits

Abstract

For wide‐ranging species in temperate environments, populations at high‐latitude range limits are subject to more extreme conditions, colder temperatures, and greater snow accumulation compared with their core range. As climate change progresses, these bounding pressures may become more moderate on average, while extreme weather occurs more frequently. Individuals can mitigate temporarily extreme conditions by changing daily activity budgets and exhibiting plasticity in resource selection, both of which facilitate existence at and expansion of high‐latitude range boundaries. However, relatively little work has explored how animals moderate movement and vary resource selection with changing weather, and a general framework for such investigations is lacking. We applied hidden Markov models and step selection functions to GPS data from wintering wild turkeys (Meleagris gallopavo) near their northern range limit to identify how weather influenced transition among discrete movement states, as well as state‐specific resource selection. We found that turkeys were more likely to spend time in a stationary state as wind chill temperatures decreased and snow depth increased. Both stationary and roosting turkeys selected conifer forests and avoided land covers associated with foraging, such as agriculture and residential areas, while shifting their strength of selection for these features during poor weather. In contrast, mobile turkeys showed relatively weak resource selection, with less response in selection coefficients during poor weather. Our findings illustrate that behavioral plasticity in response to weather was context dependent, but movement behaviors most associated with poor weather were also those in which resource selection was most plastic. Given our results, the potential for wild turkey range expansion will partly be determined by the availability of habitat that allows them to withstand periodic inclement weather. Combining hidden Markov models with step selection functions is broadly applicable for evaluating plasticity in animal behavior and dynamic resource selection in response to changing weather. We studied turkeys at northern range limits, but this approach is applicable for any system expected to experience significant changes in the coming decade, and may be particularly relevant to populations existing at range peripheries.

Behavioral-dependent recursive movements and implications for resource selection

“…Our behavioral analysis identified a restricted state characterized by shorter step lengths and less concentrated turning angles, and a mobile state characterized by longer step lengths and turning angles concentrated around zero, which was not surprising given similar findings in contemporary literature 22 , 75 . We observed that broods spent most of their time in a restricted rather than mobile state, consistent with Chamberlain et al 35 .…”

Seasonal roost selection of wild turkeys at their northern range edge

“…Numerous studies have been undertaken to assess roost selection by wild turkeys. For example, it has been proposed that turkeys choose roosts based on the benefits of being close to foraging sites, close to water, protection from predators, and because of thermoregulatory benefits (Boeker and Scott 1969, Kilpatrick et al 1988, Rumble 1992, Chamberlain et al 2000, Sasmal et al 2018, Bakner et al 2022, Gonnerman et al 2023).…”

“…Wild turkeys at northern latitudes are especially challenged to survive the winter because of restricted access to natural foods due to snow cover, longer nights, and colder temperatures (Haroldson et al 1998, Nguyen et al 2004, Niedzielski and Bowman 2015, Lavoie et al 2017, Gonnerman et al 2023). Minimizing nocturnal energy expenditure is critical to increase fasting endurance as lower temperatures require greater energy and food use to maintain thermoregulation (Paclík and Weidinger 2007).…”

“…We assessed the characteristics of roosts selected, the relationship of the roost site to the resources around it, and the potential for seasonal changes in roost selection. Winter survival is a limiting factor for sustainable populations of wild turkeys in northern latitudes (Wright et al 1996, Kane et al 2007, Niedzielski and Bowman 2015, Gonnerman et al 2023). Mammalian predation has been identified as the main cause of death in studies from the region (Niedzielski and Bowman 2015).…”