Coyotes can cause damage to a variety of resources, including livestock, poultry, and crops such as watermelons. They sometimes prey on pets and are a threat to public health and safety when they frequent airport runways and residential areas, and act as carriers of rabies. Usually, the primary concern regarding coyotes is predation on livestock, mainly sheep and lambs. Predation will be the focus of the following discussion.
Since coyotes frequently scavenge on livestock carcasses, the mere presence of coyote tracks or droppings near a carcass is not sufficient evidence that predation has taken place. Other evidence around the site and on the carcass must be carefully examined to aid in determining the cause of death. Signs of a struggle may be evident.
These may include scrapes or drag marks on the ground, broken vegetation, or blood in various places around the site. The quantity of sheep or calf remains left after a kill vary widely depending on how recently the kill was made, the size of the animal killed, the weather, and the number and species of predators that fed on the animal.
One key in determining whether a sheep or calf was killed by a predator is the presence or absence of subcutaneous (just under the skin) hemorrhage at the point of attack. Bites to a dead animal will not produce hemorrhage, but bites to a live animal will. If enough of the sheep carcass remains, carefully skin out the neck and head to observe tooth punctures and hemorrhage around the punctures.
Talon punctures from large birds of prey will also cause hemorrhage, but the location of these is usually at the top of the head, neck, or back. This procedure becomes less indicative of predation as the age of the carcass increases or if the remains are scanty or scattered.
Coyotes, foxes, mountain lions, and bobcats usually feed on a carcass at the flanks or behind the ribs and first consume the liver, heart, lungs, and other viscera. Mountain lions often cover a carcass with debris after feeding on it. Bears generally prefer meat to viscera and often eat first the udder from lactating ewes.
Eagles skin out carcasses on larger animals and leave much of the skeleton intact. With smaller animals such as lambs, eagles may bite off and swallow the ribs. Feathers and “whitewash” (droppings) are usually present where an eagle has fed.
Coyotes may kill more than one animal in a single episode, but often will only feed on one of the animals. Coyotes typically attack sheep at the throat, but young or inexperienced coyotes may attack any part of the body. Coyotes usually kill calves by eating into the anus or abdominal area.
Dogs generally do not kill sheep or calves for food and are relatively indiscriminate in how and where they attack. Sometimes, however, it is difficult to differentiate between dog and coyote kills without also looking at other sign, such as size of tracks (Fig. 2) and spacing and size of canine tooth punctures. Coyote tracks tend to be more oval-shaped and compact than those of common dogs. Nail marks are less prominent and the tracks tend to follow a straight line more closely than those of dogs. The average coyoteâ€™s stride at a trot is 16 to 18 inches (41 to 46 cm), which is typically longer than that of a dog of similar size and weight. Generally, dogs attack and rip the flanks, hind quarters, and head, and may chew ears. The sheep are sometimes still alive but may be severely wounded.
Accurately determining whether or not predation occurred and, if so, by what species, requires a considerable amount of knowledge and experience. Evidence must be gathered, pieced together, and then evaluated in light of the predators that are in the area, the time of day, the season of the year, and numerous other factors. Sometimes even experts are unable to confirm the cause of death, and it may be necessary to rely on circumstantial information. For more information on this subject, refer to the section Procedures for Evaluating Predation on Livestock and Wildlife, in this book.