Coyote Responses to Changing Jackrabbit Abundance Affect Sheep Predation

Abstract

Domestic sheep ranchers generally perceive abundances of natural prey and coyotes (Canis latrans) as important factors affecting coyote predation rates on sheep. To determine the effect of a changing natural prey base on coyote predation rates, we estimated coyote density and predation rates on ewes and lambs during part of 1 cycle of black-tailed jackrabbit (Lepus californicus) abundance on a 2,300 km 2 area of the Idaho National Engineering Laboratory in southcentral Idaho from 1979-1985. We used 100, 1.6-km scat collection lines and 80, 1.6-km flushing transects to assess coyote and jackrabbit densities, respectively. Ewe and lamb loss rates were determined from questionnaires sent to all 13 producers grazing sheep on the area. Spring coyote density varied from 0.10 to 1.39 coyotes km-2 in response to a systematic fluctuation in jackrabbit density from 0 to 243 jackrabbits km-2. Reported total loss rates of ewes and lambs varied from 2.2 to 42.1 ewes/10 5 ewe-days and 33.0 to 163 lambs/10 5 lamb-days and were linearly and directly related to coyote density (P < 0.005). Ewe and lamb loss rates were independent of jackrabbit density (P > 0.18) except for 1 year when jackrabbits were virtually absent from the study area and the loss of lambs escalated dramatically. Our data suggest the increased losses of lambs resulted from reduced buffering by natural prey.

License to Kill: Reforming Federal Wildlife Control to Restore Biodiversity and Ecosystem Function

“…Heavy cattle grazing has significantly depressed black‐tailed jackrabbit ( Lepus californicus ) density (Flinders & Hansen ), and when black‐tailed jackrabbit populations became severely depressed, ewe and lamb depredation by coyotes increased dramatically (Stoddart et al . ).…”

“…With a declining natural prey base, predators may switch to more abundant domestic stock, prompting greater demand for lethal predator control (Knowlton et al 1999). Heavy cattle grazing has significantly depressed black-tailed jackrabbit (Lepus californicus) density (Flinders & Hansen 1975), and when black-tailed jackrabbit populations became severely depressed, ewe and lamb depredation by coyotes increased dramatically (Stoddart et al 2001).…”

Factors affecting lynx predation on sheep in the French Jura

“…2000). Predation on livestock may also be greater when the availability or diversity of wild prey is low (Mech, Fritts & Paul 1988; Meriggi & Lovari 1996; Stoddart, Griffiths & Knowlton 2001), although a positive relationship has been suggested in other cases because of an increase in predator density in response to a high food supply (Nass, Lynch & Theade 1984; Yom‐Tov, Ashkenazi & Viner 1995). Additionally, evidence is growing that within a carnivore population only a small proportion of the individuals are responsible for most livestock predation, for example males whose wide‐ranging movements lead to high encounter rates with livestock (e.g.…”

Monitoring a New England Cottontail Reintroduction with Noninvasive Genetic Sampling

“…Apparent survival was highest in the first year of the reintroduction, a trend which has also been noted in reintroductions of pygmy rabbits ( Brachylagus idahoensis ; DeMay et al 2017) and riparian brush rabbits ( S. bachmani riparius ; Hamilton et al 2010). The trend of decreased survival following the initial release could be due to an increased predator response (O'Donoghue et al 1997, Sinclair et al 1998, Stoddart et al 2001), stochastic environmental and demographic processes (Crawford et al 2010, Price et al 2010), or competition with established rabbits (Hamilton et al 2010). Competition could have been a factor in this reintroduction because territoriality and aggressive conspecific interactions among males have been documented in both New England cottontails (Tefft and Chapman 1987) and eastern cottontails (McKinney 1970, Brenner and Flemming 1979).…”