nature of food resources (Camenzind, 1978; Bowen, 1981; Bekoff & Wells, 1986; Gese, Rongstad, & Mytton, 1988a; see also Gese, Rongstad, & Mytton, 1988b). Pack members share in territorial defence and some serve as helpers for rearing young and for defending territories outside the breeding season. At least in northern climates, packs typically form when there is sufficient food in late autumn and winter to allow young-of-the-year to form strong social bonds with older pack members; this results in some young-of-the-year remaining with their parents and older siblings. Diet and Hunting Behaviour Coyotes enjoy a catholic diet including plant and animal matter (including reptiles; Hernndez, Delibes & Hiraldo, 1944) and inanimate objects. Although coyotes are opportunistic predators, they can also be very selective hunters in certain situations (e.g. Hernndez & Delibes, 1944). Diet varies greatly both seasonally and geographically, as do the methods by which prey are acquired. Coyotes are active predators relying primarily on vision whilst hunting, and they have been observed to fish and climb trees in pursuit of food. They are also successful scavengers. The success of hunting attempts varies with age, prey type, grass height, and snow depth. A study by Bekoff & Wells (1986) showed that adults and juveniles were about equally successful when they hunted small rodents (about 20-25% of the time). Adults and juveniles also enjoyed their highest success rate when they hunted gophers and were least successful when they hunted voles. Coyotes were also more successful when they hunted small rodents in