Most studies of urban/suburban coyotes have found that coyotes in these areas relied predominantly on natural food sources rather than human generated food such as trash, domestic animals, pet food, and domestic fruit (Gerht and Riley 2010; Morey et al. 2007). The most common food items were leporids (rabbits) and rodents and occasionally deer or fruit. However, coyotes in more urbanized areas, did consume more human generated food than their rural counterparts (2% to 35%: Gerht and Riley 2010). Of particular concern to owners’ of lost or outdoor-access cats is how frequently coyotes eat cats. Based on observations of coyotes in Tuscan, Arizona, Grubbs and Krausman (2009) reported the alarming find that cats constituted 42% of coyote diets. However, the majority of studies of urban coyotes have found that cats occurred in only 1%- 2% or less of coyote diets (Gerht 2006; Gerht and Riley 2010; Morey et al. 2007). In a few studies, cat remains were found in larger frequencies. Morey et al. (2007) found that 6.7% of scats contained cat in the site with the most urban development. Quinn’s (1997) study in western Washington found a higher percentage of cat remains in coyote scat with an average of 7.8%. In the residential study area, cat was the most abundant mammalian food item at 13.1% though fruit was considerably more common for all items (42.6%). However, Quinn (1997) only recorded the “dominant” prey item for each scat, which would lead to greater representation for those items (i.e. if a scat contained mostly cat hair and only one mouse, he only recorded the cat remains for that scat). In the highest incidence of coyote predation on cats, Crooks and Soule (1999) found that 21% of 219 coyote scats contained cat remains. This study took place in southern California were attacks on cats may be the highest in the US.
The difference between Grubbs and Krausman’s (2009) study and the other research studies is that their estimates were based on a small number of observations (45) of coyotes consuming prey or fruit while the majority of food habits studies assess coyote diets by analyzing scat (feces). Scat analysis is most commonly reported as percent occurrence, which can be measured with one of several methods. The most common methods (a) measure percent occurrence as the number of occurrences of a diet item/ total number of occurrences of all diet items or (b) measure occurrence as the number of scats with an item/ total number of scats analyzed. In the case of (b), the percentages will often not add up to 100% because some scats contain more than one diet item. For example, if the percent occurrence of rodents was 30%, then either (a) 30% of the total items consumed by coyotes were rodents or (b) 30% of all scats analyzed contained rodent remains.
Although scat analysis is a convenient way to study dietary habits, it does have some well known errors. Percent occurrence is biased by the size of the prey consumed such that larger prey items are overrepresented. For example, if a coyote eats a mouse, the entire mouse will be present in one scat, but when a coyote eats a deer, the same deer may be present in several scats resulting in a higher percent occurrence for deer even though the same number of mice and deer were consumed. It is also not possible to determine whether prey items consumed were killed by the predator or scavenged from an already dead animal. Lastly, if coyotes are killing cats but not consuming them (as might occur in interspecific competition), then scat analysis would under-represent the number of cats being killed. However, Grubbs and Krausman (2009) found that coyotes consumed cats in 18 out of 19 observed kills, and the coyote only left the one cat uneaten because it was disturbed by a person. Given my personal experience studying coyotes in Yellowstone National Park, I also find it hard to believe that coyotes would not consume any animal that they killed or found dead. In contrast, wolves would frequently kill coyotes but not consume them.
For more information on coyote predation on cats, check out these articles “Observations of Coyote Predation on Cats” and “More Observations on Coyote – Cat Interactions: what can we learn?” I have also created a file that contains this discussion and the diet analysis research tables from several studies.
If you find yourself strongly disagreeing with this article, then you may live in an area where coyotes do indeed eat more cats. If you are concerned that your cat may have been killed by a coyote, then you should read this article: “Understanding Coyote Behavior in Urban/Suburban Areas and Assessing Risk to Cats.”
Crooks, K.R. and M.E. Soule. 1999. Mesopredator release and avifaunal extinctions in a fragmented system. Nature 400: 563-566.
Grubbs, Shannon E. and Paul R. Krausman. 2009. Observations of Coyote – Cat Interactions. Journal of Wildlife Management 73(5): 683-685.
Morey, Paul S. , Eric M. Gese, and Stanley Gehrt. 2007. Spatial and Temporal Variation in the Diet of Coyotes in the Chicago Metropolitan Area. American Midland Naturalist 158: 147-161.
Gehrt, Stanley and Seth P.D. Riley. 2010. “Coyotes (Canis latrans)” in Urban Carnivores: Ecology, Conflict, and Conservation. Gehrt, Stanley, D., Seth P.D. Riley, and Brian L. Cypher, editors. The John Hopkins University Press.
Gehrt, Stanley D. 2006. Urban Coyote Ecology and Management. Ohio State University Extension Bulletin 929. 32 pp.
Quinn, Timothy. 1997. Coyote Food Habits in Three Urban Habitat Types of Western Washington. Northwest Science 71(1): 1-5.