Quote:Steve Allen, who used to be the furbearer biologist at the North Dakota Game & Fish Dept., did a study of the relationship between coyotes and fox. I couldn't find a link to it so if someone does find it, please paste it in this thread.
Quote:OBSERVED INTERACTIONS BETWEEN COYOTES AND RED FOXES ALAN B. SARGEANT AND STEPHEN H. ALLEN U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, Jamestown, ND 58402 North Dakota Game and Fish Department, Bismarck, ND 58501 Coyotes (Canis latrans) are believed to influence the distribution and abundance of red foxes (Vulpes vulpes) (Sargeant, 1982). Examples of inverse relations in abundance of the two species are numerous (Dekker, 1983; Goldman, 1930; Johnson and Sargeant, 1977; Linhart and Robinson, 1972; Sargeant, 1982; Schmidt, 1986). Populations of both species are composed primarily of territorial family groups. In allopatric popu- lations, territories tend to be contiguous and nonoverlapping (Andelt, 1985; Sargeant, 1972). In sympatric populations, red fox territories straddle the periphery or are located largely outside of coyote territories (Major and Sherburne, 1987; Sargeant et al., 1987; Voigt and Earle, 1983). Avoidance of coyotes by foxes is believed to be the principal cause of spatial separation (Sargeant et al., 1987). Few published accounts of interactions between coyotes and red foxes are available. Both species tend be nocturnal and secretive; interspecific encounters rarely are seen. For example, Major and Sherburne (1987), Sargeant et al. (1987), and Voigt and Earle (1983) observed no interspecific encounters during extensive radiotracking of sympatric coyotes and red foxes. Sargeant et al. (1987) found that coyotes and red foxes from families with overlapping territories avoided interspecific encounters. However, Goldman (1930), Voigt and Earle (1983), and Young and Jackson (1951:93) reported that coyotes sometimes kill red foxes, especially in traps. Dekker (1983) observed several instances of coyotes chasing red foxes, and Major and Sherburne (1987) reported coyotes killed one-four red foxes in a previous study. Dekker (1983) also observed adult foxes barking at coyotes near fox-rearing dens; Voigt and Earle (1983) reported an instance of coyotes and red foxes rearing pups about 1 km apart. In this paper we report additional accounts of interactions between coyotes and red foxes that aid in understanding relations between these species. We solicited accounts of coyote-red fox interactions from university and natural-resource-agency personnel in several states and provinces of the midcontinent region and from other individuals in the region known or recommended to us. We requested accounts of coyotes killing red foxes and vice versa, coyotes chasing red foxes and vice versa, coyotes visiting rearing dens of red foxes when pups were present and vice versa, coyotes and red foxes simultaneously rearing pups in nearby dens, and coyotes and red foxes near each other without evidence of antagonism. We received 42 accounts of coyote-red fox interactions from 28 people (includes two accounts made us). Except for one observation made in California in 1965, they were from the midcontinent region, mostly North Dakota, and were made during 1970-1985. Most (71%) accounts described aggression by coyotes toward red foxes. Eight accounts described free- ranging foxes known or presumed to have been killed by coyotes. In a September interaction, two coyotes were observed traveling together along a hay meadow when a fox took flight. The coyotes chased and quickly killed the fox. Later that day the observer found and examined another freshly killed fox in the same area; the fox had been bitten severely, presumably by coyotes. In a January interaction, tracks in snow showed two coyotes had chased and killed a fox but left it intact. In an April interaction, tracks in snow showed two coyotes pursued a fox (lactating female) into a shallow pond where it was caught, pulled to shore, and killed. The four other interactions each involved single, freshly killed male foxes found during September-February. Three of these were examined and each had multiple severe bites on various parts of the body. Seventeen accounts described trapped (leg-hold) or snared foxes killed by coyotes. Many of these foxes were described as mauled, ripped apart, or fed upon. Five accounts described single coyotes chasing single foxes. Two chases were in spring; dates of others were not provided. One chase was interrupted when the coyote (adult female) was shot. We received one account of a fight between a coyote and a fox. It occurred in January and was observed for about 10 min before being interrupted. The coyote repeatedly attempted to catch the fox by biting in the flanks but the fox escaped by jumping high and running. Examination of snow at the site of the fight revealed coyote and fox fur, and a trail of blood left by the fox. We received three accounts involving a total of eight fox pups found dead at or near six rearing dens foxes; all were believed to have been killed by coyotes. We found four of the pups, all on the same day, three dens located within 3 km of each other in an area believed to have been The dens continued being used by remaining live fox pups. The four dead of two not badly decomposed revealed bite marks on the head or throat. One account described defensive behavior by an adult fox toward an adult were seen approaching a fox-rearing den that had six pups above ground. Three the others remained above ground. The adult fox remained about 30 m behind circled it, and "howled hoarsely and loudly." The coyote walked stiffly with or chased the fox. When the coyote was about 50 m from the den it turned which it had come, this time with the fox ahead of it. The fox then ceased We received three accounts of simultaneously occupied coyote- and red-fox-each other. The dens were 0.8, 1.2, and 1.6 km apart; in the latter instance island. Four accounts described interspecific indifference; all occurred during winter. One person reported that while conducting aerial deer (Odocoileus sp.) surveys he often saw coyotes and red foxes, apparently unconcerned with each other, in the same 0.65-km2 unit. One account was of a coyote and red fox observed simultaneously feeding on remains of a butchered cow at an occupied farmstead during extremely cold weather. Another was of a fox observed trotting downwind of a bedded coyote. The fox detected the coyote and circled to within 20 m of it. After a few minutes the fox left; the coyote left in another direction a few minutes later. The fourth account was of a coyote that came within 100 m of two foxes mating. The coyote watched the foxes for several minutes then left. These accounts and those cited previously show that coyotes often are overtly antagonistic to red foxes. We obtained no reports of red foxes being antagonistic to coyotes except when attacked by coyotes or when their pups were approached by coyotes. The fact that coyotes are larger than foxes and that two or more coyotes often travel together and may cooperate in killing prey (Andelt, 1985; Young and Jackson, 1951:97) makes red foxes vulnerable to coyote-inflicted mortality. Antagonistic behavior by coyotes toward red foxes occurs throughout the year and may be directed at foxes of all age and sex classes. The aggression can result in death of adult foxes although the frequency of such mortality among free-ranging foxes may be low. Voigt and Earle (1983) reported no coyote-inflicted mortality among 117 red foxes radiotracked in a coyote-inhabited area of Ontario; Major and Sherburne (1987) reported no coyote-inflicted mortality among four red foxes radiotracked in a coyote-inhabited area of Maine. Sargeant et al. (1987) found no coyote-inflicted mortality among 22 red foxes under radio sur- veillance for 2,518 fox-days in a coyote-inhabited area of North Dakota although one tagged (not radio equipped) juvenile fox apparently was killed by coyotes (included in our results). The relatively common occurrence of coyotes killing foxes in traps likely results from inability of trapped foxes to flee or adequately defend themselves. Many trapped foxes reported killed by coyotes possibly were dispersing juveniles caught inside coyote territories. Long-range dispersal of juvenile foxes occurs during fall and winter (Storm et al., 1976), when foxes are trapped for fur, and dispersing foxes travel through coyote territories (Voigt and Earle, 1983). The accounts we received showed that coyotes occasionally kill fox pups at dens but there is no evidence this is a major source of mortality for foxes living among coyotes. Dekker (1983) inferred that red foxes often den in the immediate vicinity of farms to seek refuge from coyotes but reported no instances of coyote- inflicted mortality on fox pups. Sargeant et al. (1987) also found that in sympatric populations red foxes den closer to occupied farms and roads than coyotes. During 1980-1984 we visited 48 fox-rearing dens on a 313- km2 area in northwest North Dakota where coyotes were common; we found no evidence of coyote disturbance to the dens or of coyotes killing fox pups. The arrangement of the coyote and fox dens on that area indicated families of each species were separated spatially in the manner described by Major and Sherburne (1987), Sargeant et al. (1987), and Voigt and Earle (1983); most fox dens were near farms and roads. Although red foxes have reason to fear coyotes, they frequently may be near coyotes without showing apparent concern, and coyotes encountering foxes may not respond aggressively. The observed communal feeding by a coyote and fox, and the reported instances of coyotes and foxes rearing pups near each other, reveal the high degree of interspecific tolerance that can occur. Nevertheless, it is advantageous for foxes to avoid encounters with coyotes because each encounter includes risk of injury or death. This mixture of coyote aggression and indifference toward red foxes may explain gradual changes in fox populations in the wake of changes in coyote populations (Sargeant, 1982) and the presence of some red foxes among coyotes for years (Sargeant et al., 1987).
