To dare or not to dare? Risk management by owls in a predator–prey foraging game

Abstract

In a foraging game, predators must catch elusive prey while avoiding injury. Predators manage their hunting success with behavioral tools such as habitat selection, time allocation, and perhaps daring-the willingness to risk injury to increase hunting success. A predator's level of daring should be state dependent: the hungrier it is, the more it should be willing to risk injury to better capture prey. We ask, in a foraging game, will a hungry predator be more willing to risk injury while hunting? We performed an experiment in an outdoor vivarium in which barn owls (Tyto alba) were allowed to hunt Allenby's gerbils (Gerbillus andersoni allenbyi) from a choice of safe and risky patches. Owls were either well fed or hungry, representing the high and low state, respectively. We quantified the owls' patch use behavior. We predicted that hungry owls would be more daring and allocate more time to the risky patches. Owls preferred to hunt in the safe patches. This indicates that owls manage risk of injury by avoiding the risky patches. Hungry owls doubled their attacks on gerbils, but directed the added effort mostly toward the safe patch and the safer, open areas in the risky patch. Thus, owls dared by performing a risky action-the attack maneuver-more times, but only in the safest places-the open areas. We conclude that daring can be used to manage risk of injury and owls implement it strategically, in ways we did not foresee, to minimize risk of injury while maximizing hunting success.

Hunger mediates apex predator's risk avoidance response in wildland–urban interface

“…Our case study provides one of the first direct demonstrations of hunger state governing the movement decisions underlying the foraging behaviours in a large mobile predator. Only a few experimental examples exist of hunger-mediated phenomena in higher trophic levels (Berger-Tal et al, 2009;Embar et al, 2014). Hunger measures in large carnivore studies have been inferred from belly size estimates (Packer, Swanson, Ikanda, & Kushnir, 2011) or time since last kill (McPhee et al, 2012), but were employed as response variables rather than predictor variables.…”

“…A more direct, universal and temporally sensitive proxy for a predator's energetic state is hunger. Although hunger‐mediated decision making was conceptualized at the forefront of optimal foraging theory (Emlen, ), implied in theoretical models (Charnov, ), and demonstrated experimentally with small and short‐lived organisms (Caraco, ), case studies in an experimental setting (penned subjects) with higher trophic levels of carnivores are uncommon and relatively recent (small canid: Berger‐Tal et al., ; avian predator: Embar, Raveh, Burns, & Kotler, ). Attempts to demonstrate hunger mediated risk aversion in large predators in a natural landscape have been unfruitful (Cooper, Pettorelli, & Durant, ; Hilborn, Pettorelli, Orme, & Durant, ).…”

Nonconsumptive effects of hunting on a nontarget game bird

“…Hunting disturbance is known to cause antipredator behavior in prey as a way to mitigate the risk of predation (Lima & Bednekoff, 1999). Prey species attempt to mitigate these risks through behaviors such as altered habitat use and increased vigilance (Creel, Winnie, Maxwell, Hamlin, & Creel, 2005;Clinchy et al, 2016;Embar, Raveh, Burns, & Kotler, 2014;Frid & Dill, 2002;Lima & Dill, 1990). However, antipredator behavior can have fitness costs in terms of reduced foraging effort, greater net energy loss, and increased vulnerability to other predators (Lima & Bednekoff, 1999;Morrison, 1999;Downes, 2001;Eklov & Van Kooten, 2001;Creel, 2018).…”

An adaptive behavioural response to hunting: surviving male red deer shift habitat at the onset of the hunting season

“…One widespread response to reduce predation risk is to shift habitat use away from areas with high predation risk (Creel, Winnie Jr, Maxwell, Hamlin, & Creel, 2005;Valeix et al, 2009). Across a range of taxa, such a habitat shift involves a trade-off between access to resources and safety (Breviglieri, Piccoli, Uieda, & Romero, 2013;Embar, Raveh, Burns, & Kotler, 2014;Heithaus, Wirsing, Burkholder, Thomson, & Dill, 2009;Nonacs & Dill,1990). A typical situation for large grazing mammals is that individuals have to choose between open habitats with good foraging opportunities, but where they are visible to predators, and habitats that provide more cover from potential dangers but which might limit foraging efficiency (Godvik et al, 2009;Werner, Gilliam, Hall, & Mittelbach, 1983).…”