Predator hunting behaviour and prey vulnerability

Abstract

Summary1. Game theoretic models of how animals manage predation risk have begun to describe predator responses to prey behaviour relatively recently. This is partly because our understanding of how terrestrial predators select vertebrate prey is often limited to numerical and functional responses to measures of prey abundance. Prey vulnerability, however, may improve our understanding of predation because predators could maximize foraging success by selecting prey on this basis. 2. We tested the hypothesis that sparrowhawks ( Accipiter nisus L.), a typical generalist predator, hunt redshanks ( Tringa totanus L.), a favoured prey species on coastal shores, primarily on the basis of their vulnerability rather than their abundance. 3. Five direct measures or indicators of redshank behaviour predicted sparrowhawk attack success in a multipredictor statistical model and therefore serve as measures of redshank vulnerability. 4. These and other vulnerability measures influenced whether sparrowhawks decided to hunt redshanks on saltmarsh habitat. A model that included most of these measures predicted correctly whether sparrowhawks hunted redshanks (attack decision) 90% of the time and accounted for up to 75% of variation. Prey abundance accounted for no additional variation. 5. Thus the hunting behaviour of some predators can only be predicted well by several highly dynamic and interacting factors related to prey vulnerability. These results mean that, theoretically at least, the management of prey populations may sometimes be achieved best by manipulating prey vulnerability, rather than by culling their predators.

Prey Behavior, Age‐Dependent Vulnerability, and Predation Rates

“…It is possible that the fawns' vulnerability to capture declined more from summer to winter than was apparent from the data we gathered by watching coyotes hunt deer; we cannot completely disentangle prey vulnerability from hunter motivation (Downes 2002;Quinn and Cresswell 2004). We suspect that coyotes were generally more motivated by hunger to attack and capture deer and to accept risk of injury in winter than in summer.…”

“…Because deep snow can hinder an ungulate's ability to flee (Messier and Barrette 1985;Paquet 1992), it is plausible that the mule deer's tactics of confrontation would be more effective than the white-tailed deer's use of flight when encountering predators in deep snow. Low-quality food, energetic stress, or disease that impairs an animal's physical condition and ability to respond effectively to predators (Lindström et al 2003;Quinn and Cresswell 2004;Martin et al 2006) could lead to annual variation in the shape of vulnerability curves. Fawns might have been more vulnerable to capture in years in which they and-at least in the case of mule deer-the females that protect them were in poorer condition.…”

Female mate choice based upon male motor performance

“…The elaborate stotting that prey such as Thomson's gazelles, Gazella thomsoni, perform at the beginning of a predator attack suggests that the predators are capable of detecting slight differences in the motor performance of prey (FitzGibbon & Fanshawe 1988). It is also well known that predators efficiently identify weak, injured or sick prey (Mills, 1990;Quinn and Cresswell, 2004;Martin et al, 2006;Wright et al, 2006). In summary, natural selection on predators has probably enhanced animals' ability to detect subtle differences in the motor performance of potential prey.…”

Comparisons and Trends in White-tailed Deer, <em>Odocoileus virginianus</em>, Body Fat in Northeastern Minnesota, 1974-1990

“…Predator-prey relationships have been discussed extensively through the years, yet what is still uncertain is the underlying mechanism of predicting predation mortality (Quinn and Cresswell 2004). One foraging theory of predators is they preferentially select the more vulnerable prey (e.g.…”