Response of neighboring coyotes (Canis latrans) to social disruption in an adjacent pack

Territoriality is an important mechanism by which social carnivores limit or exclude potential competitors from males, food, and space. The response of neighboring conspecifics to social disruption in an adjacent social unit has been rarely documented, owing to the difficulty of observing secretive or noctumal carnivores. We observed 54 coyotes (Canis latrans) from five resident packs, plus five transient animals, for 2507 h from January 1991 to June 1993 in the Lamar River Valley, Yellowstone National Park, Wyoming. We documented the spatial response of three neighboring coyote packs to the social disruption in an adjacent fourth pack caused by the death of the alpha male and subsequent temporary abandonment of the territory by the alpha female. One of the three packs shifted its space-use pattern into part of the adjacent pack's territory and maintained occupancy of the newly acquired area even when the alpha female returned with a new mate. Neither food shortage nor prey availability was a contributing factor. The absence of the alpha pair maintaining territorial boundaries allowed the adjacent pack to take over part of the unoccupied area.