Predator facilitation or interference: a game of vipers and owls

Abstract

In predator-prey foraging games, the prey's reaction to one type of predator may either facilitate or hinder the success of another predator. We ask, do different predator species affect each other's patch selection? If the predators facilitate each other, they should prefer to hunt in the same patch; if they interfere, they should prefer to hunt alone. We performed an experiment in a large outdoor vivarium where we presented barn owls (Tyto alba) with a choice of hunting greater Egyptian gerbils (Gerbillus pyramidum) in patches with or without Saharan horned vipers (Cerastes cerastes). Gerbils foraged on feeding trays set under bushes or in the open. We monitored owl location, activity, and hunting attempts, viper activity and ambush site location, and the foraging behavior of the gerbils in bush and open microhabitats. Owls directed more attacks towards patches with vipers, and vipers were more active in the presence of owls. Owls and vipers facilitated each other's hunting through their combined effect on gerbil behavior, especially on full moon nights when vipers are more active. Owls forced gerbils into the bushes where vipers preferred to ambush, while viper presence chased gerbils into the open where they were exposed to owls. Owls and vipers took advantage of their indirect positive effect on each other. In the foraging game context, they improve each other's patch quality and hunting success.

Hunting‐mediated predator facilitation and superadditive mortality in a European ungulate

“…Instead, the results likely reflect the behavioral plasticity of predators that enables them to capitalize on short-term changes in prey vulnerability. Our findings thus suggest that predator facilitation may prompt predators to increase their activity in their preferred habitat in the presence of other predators that hunt the same prey (Embar et al, 2014 , 2000). Thus, the roughly 50% increase in lynx deer kills we found during the hunting season implies that each lynx would kill five additional deer during the 10-week hunting period.…”

“…The activity and hunting strategy of predators themselves may depend on whether other predators feeding on the same prey co‐occur or not (Matsuda, Abrams, & Hori, ). For example, Embar, Raveh, Hoffmann, and Kotler () showed experimentally that vipers ( Cerastes cerastes ) and owls ( Tyto alba ), both predators of gerbils ( Gerbillus pyramidum ), adjust their hunting activity depending on the presence of the other predator. By doing so, both predators may be able to improve their own hunting success.…”

The ontogeny of antipredator behavior: age differences in California ground squirrels (Otospermophilus beecheyi) at multiple stages of rattlesnake encounters

“…In addition, prolonged bouts of tail flagging may be costly because they could draw the attention of other predators (Broom and Ruxton 2012). Thus, rattlesnake-induced tail flagging may facilitate attacks from other predatory species (e.g., Kotler et al 1992;Embar et al 2014), which pups should avoid due to their high vulnerability. Associative learning facilitated by conspecifics is likely the main process by which pups develop adult-like snake responses.…”

Mobility of a small mammalian predator changes according to the activity patterns of potential intraguild predators

“…Our results show that both predator facilitation and antipredatory behaviours are involved in interactions between weasels and avian predators. Such behavioural responses to the presence of intraguild predators can further cause risk enhancement or reduction in shared prey (Charnov et al ., ; Kotler et al ., ; Korpimäki et al ., ; Embar et al ., ). In an earlier study, we observed risk reduction in shared prey between owls and weasels (Hoset et al ., ), suggesting that hunting simultaneously did not improve the hunting efficiency of the predators.…”

“…Bischof et al ., ), whereas interactions between predators with different hunting strategies often show positive effects (e.g. Korpimäki et al ., ; Embar et al ., , this study). We recommend that studies on multi‐predator effects need to assess the dominance of predator hunting modes and relationships between small and large predator species to obtain a full perspective of these effects.…”