Contingent strategies of risk management by snowshoe hares

Abstract

Prey individuals employ several adaptive behaviours to reduce predation risk. We need to learn how those behaviours interact in an overall strategy of risk management, how strategies vary with changing conditions, and whether some behaviours might compensate for others. I addressed these issues with manipulative experiments evaluating how snowshoe hares’ ( Lepus americanus) vigilance varies with their giving-up densities (GUDs) in artificial food patches. I tested whether the results, collected when there was no evidence of predation, were congruent with an earlier study under higher predation. When predator sign was common, vigilance depended directly on habitat. But when risk was low, habitat’s influence on vigilance was indirect. Hares were least vigilant during the new moon where the distance to escape habitat was far, but only in open risky habitat. Hares were more vigilant during the full moon, but only at stations far from escape habitat. Moon phase and additional cover had no effect on GUDs that were highest at open risky stations far from escape habitat. The results suggest that reduced risk allowed hares to allocate less time to vigilance, but they needed to forage for similar amounts of food during each moon phase to maintain their energetic state.

Sex‐dependent habitat selection modulates risk management by meadow voles

“…Intraspecific competition can also reduce foraging efficiency. Winter-foraging snowshoe hares used vigilance to manage risks from both predators and competing hares (Morris, 2019). Vigilance reduces foraging efficiency that increases the forager's GUD.…”

“…Among these, predation risk and its attendant fear are often invoked to account, indirectly, for many patterns in the behavior of individuals, the dynamics of their populations, and the structure of ecological communities (Abrams, 1984; Blumstein, 2020; Brown et al, 1999; Holt, 1977, 1984; Holt & Bonsall, 2017; Laundré et al, 2001; Peacor & Werner, 2000, 2001; Zanette et al, 2011; and numerous others). The presumed importance of predation risk suffers, however, from convincing evidence (Sheriff et al, 2020, but see Allen et al, 2022 and its accompanying appendix) and from studies documenting similar behavioral and foraging responses to intra‐ (Morris, 2019) and interspecific competitors (Dupuch, Morris, Ale, et al, 2014; Dupuch, Morris, & Halliday, 2014; Halliday & Morris, 2013; Morris, 2009). Competitive effects include injury during aggressive interactions, limited access to resources, breeding sites and mates, and pilferage of cached foods (Dittel & Vander Wall, 2018) that reduce survival and reproductive opportunities.…”