If you are a rabbit a hunting coyote may be your worst nightmare. Coyotes are smart and efficient predators, but it turns out that coyotes and other predators also have a bit of a bullying streak. Coyotes will dominate smaller canines like foxes and push them out of the best habitat and even kill them (wolves will also do the same thing to coyotes). This extreme competition is called intraguild predation, because coyotes are preying on another predator in the same level of the food chain, or animals in the same guild, instead of traditional predation on rodents or other animals lower in the food chain (Ritchie and Johnson 2009).
Competition for the same resources is one of the fundamental concepts of ecology, and the pressure of competition usually causes similar species, like coyotes and foxes, to evolve slightly different hunting strategies or preferred habitats to avoid some of that competition. For example wolves hunt valley bottoms and eat deer and elk, while coyotes hunt along forest field edges and eat rabbits and small rodents. However, canine predators tend not tolerate species that compete even a little bit, and wolves will kill coyotes and coyotes will kill foxes when these species live in the same place.
Coyotes are effective intraguild predators with all fox species, and kill and exclude gray foxes (Henke and Bryant 1999, Fedriani et al. 2000), lower swift fox density (Thompson and Gese 2007), and compete with red foxes for prey and preferred habitat (Theberge and Wedeles 1989). Where coyotes and foxes overlap coyotes are actually killing foxes, not just competing with them for prey and habitat. Wolves have the same effect on coyotes. When wolves were reintroduced to the greater Yellowstone ecosystem, coyote numbers dropped (Berger and Conner 2008), and the effects of this change rippled out into the larger mammal community. Coyotes are the main predator of pronghorn antelope calves, and wherever wolves established territories coyote populations went down and pronghorn calf survival went up (Berger et al. 2008).
Even though coyotes affect foxes in the same way that wolves affect coyotes, they do have different effects on the mammal community as a whole. Since wolves (and other apex predators like cougars) kill large prey, the leftovers from wolf kills support a whole community of scavengers and omnivores, including animals as large as bears (Wilmers et al. 2003). Coyotes kill smaller prey and do not support other animals in the same way.
Interactions between predators are fascinating but complex, and to conserve diverse natural areas we need to know how they work. The extensive camera trapping of eMammal will be used to shed some light on these patterns in the east and help conservation.
Berger, K. M., and M. M. Conner. 2008. RECOLONIZING WOLVES AND MESOPREDATOR SUPPRESSION OF COYOTES: IMPACTS ON PRONGHORN POPULATION DYNAMICS. Ecological Applications 18:599–612.
Berger, K. M., E. M. Gese, and J. Berger. 2008. INDIRECT EFFECTS AND TRADITIONAL TROPHIC CASCADES: A TEST INVOLVING WOLVES, COYOTES, AND PRONGHORN. Ecology 89:818–828.
Fedriani, J. M., T. K. Fuller, R. M. Sauvajot, and E. C. York. 2000. Competition and intraguild predation among three sympatric carnivores. Oecologia 125:258–270.
Henke, S. E., and F. C. Bryant. 1999. Effects of Coyote Removal on the Faunal Community in Western Texas. The Journal of Wildlife Management 63:1066–1081.
Ritchie, E. G., and C. N. Johnson. 2009. Predator interactions, mesopredator release and biodiversity conservation. Ecology Letters 12:982–998.
Theberge, J. B., and C. H. R. Wedeles. 1989. Prey selection and habitat partitioning in sympatric coyote and red fox populations, southwest Yukon. Canadian Journal of Zoology 67:1285–1290.
Thompson, C. M., and E. M. Gese. 2007. FOOD WEBS AND INTRAGUILD PREDATION: COMMUNITY INTERACTIONS OF A NATIVE MESOCARNIVORE. Ecology 88:334–346.
Wilmers, C. C., R. L. Crabtree, D. W. Smith, K. M. Murphy, and W. M. Getz. 2003. Trophic facilitation by introduced top predators: grey wolf subsidies to scavengers in Yellowstone National Park. Journal of Animal Ecology 72:909–916.