Prey selection and dietary flexibility of three species of mammalian predator during an irruption of non-cyclic prey

Abstract

Predators often display dietary shifts in response to fluctuating prey in cyclic systems, but little is known about predator diets in systems that experience non-cyclic prey irruptions. We tracked dietary shifts by feral cats (Felis catus), red foxes (Vulpes vulpes) and dingoes (Canis dingo) through a non-cyclic irruption of small mammalian prey in the Simpson Desert, central Australia. We predicted that all three predators would alter their diets to varying degrees as small mammals declined post irruption, and to test our predictions we live-trapped small mammals through the irruption event and collected scats to track predator diets. Red foxes and dingoes included a broader variety of prey in their diets as small mammals declined. Feral cats did not exhibit a similar dietary shift, but did show variable use and selectivity of small mammal species through the irruption cycle. Results were largely consistent with prior studies that highlighted the opportunistic feeding habits of the red fox and dingo. They also, however, showed that feral cats may exhibit less dietary flexibility in response to small mammal irruptions, emphasizing the importance of tracking predator diets before, during and after irruption events.

Coyote diet patterns in the Mojave Desert: implications for threatened desert tortoises

“…Such a shift also is consistent with optimal foraging theory predictions (Pianka 1978;Stephens and Krebs 1986;MacCracken and Hansen 1987). Increased dietary breadth in response to a decline in preferred food items is a common functional response among medium-size carnivores and has been observed among coyotes elsewhere (MacCracken and Hansen 1987;Cypher et al 1994), dingoes (Corbett 1995;Paltridge 2002), red foxes (Vulpes vulpes) (Errington 1937;Spencer et al 2017), kit foxes (Kelly 2017), bobcats (Lynx rufus) (Beasom and Moore 1977;McKinney and Smith 2007), Iberian lynx (Lynx pardina) (Delibes 1980), and caracals (Felis caracal) (Palmer and Fairall 1988).…”

Phenotypic integration in feliform carnivores: Covariation patterns and disparity in hypercarnivores versus generalists

“…Hypercarnivorous species are most often characterized by the vertebrate flesh proportion composing their diet. Nonetheless, detailed diet information is not always available, the estimation of meat proportion is subject to methodological issues, and the diet may vary depending on prey availability (Bianchi et al 2014;Steenweg et al 2015;Machovsky-Capuska et al 2016;Dunlop et al 2017;Spencer et al 2017;Nielsen et al 2018). Interestingly, Andersson and Werdelin (2003) recorded a drop in disparity in limbs of hypercarnivores for species over 20 kg suggesting that extensive constraints imposed by heavy body mass and ecological specializations could largely impact shape diversity.…”

Resource pulses affect prey selection and reduce dietary diversity of dingoes in arid Australia

“…Many small and medium‐sized mammal species respond to these short‐lived flushes of primary productivity with a population irruption (boom), causing dingoes (Spencer et al. ) and other predators such as raptors (McDonald & Pavey ) and feral cats Felis catus (Pettigrew , Yip et al. ), to alter their diet and exploit hyper‐abundant prey.…”

“…Letnic & Dickman 2006, Pavey et al 2008. Many small and medium-sized mammal species respond to these short-lived flushes of primary productivity with a population irruption (boom), causing dingoes (Spencer et al 2017) and other predators such as raptors (McDonald Fig. 1.…”