Coyotes are considered opportunisitic omnivores and will eat just about anything. As the seasons and the availability of foods change, so does the coyote’s diet. During the summer, coyotes feed upon berries and insects. Small mammals are an important prey of choice during the fall and into the winter. As winter becomes harder and small mammal populations decline, coyotes turn toward their largest prey – white-tailed deer.
It is not uncommon to come upon deer carcasses in the winter which have been cleaned within an inch of their life by coyotes, illustrating their preference for this ungulate. However, the majority of deer carcasses consumed by coyotes are not killed by them, but are discovered as carrion or road kills. Coyotes infrequently kill healthy adult deer. Occasionally, working in packs, they will chase them down. Scat dissection shows that in late spring, coyotes prey on fawns.
A study of coyote predatory behavior in New York state several years ago found that during the winter, only 8% of adult deer carcasses visited by coyotes had been killed conclusively by coyotes. The remaining 92% were scavenged by coyotes after being killed by vehicles and other injuries. The adult deer that were killed by coyotes had severe pre-existing injuries and were likely to die from other causes in the absence of coyote predation.