EXPLORING TERRITORY QUALITY IN THE NORTH-AMERICAN RED SQUIRREL THROUGH REMOVAL EXPERIMENTS

If territory quality affects the fitness of its holder, then relativel y unsuccessful individuals should relocate if given the opportunity to appropriate a higher quality territory. Relocation by these animals, however, may be prevented by habitat saturation, poor competitive abil ity, or the costs of relocating. We conducted two removal studies that created numerous territory vacancies in a population of the North Ame rican red squirrel (Tamiasciurus hudsonicus), thus providing favourabl e conditions for relocation. In both experiments, we tested whether no nbreeding females were more likely to relocate than breeding females, presumably because they (the nonbreeders) occupied relatively poor-qua lity territories. In our first experiment we permanently removed most of the squirrels from a study site and monitored the relative proporti ons of the remaining nonbreeding and breeding females that relocated. In our second experiment we monitored the response of squirrels to vac ant territories that had been previously held by nonbreeding and breed ing females, as well as by males. We also monitored the behaviour of s quirrels that did not hold territories (dispersing offspring), as thes e individuals would not experience the same costs of relocation as adu lts. Our experiments showed that neither category of female was likely to relocate, regardless of the type of territory available. Both resi dents and dispersing offspring displayed no biases towards vacant terr itories that previously belonged to nonbreeding or breeding females or to males. Relocation does not appear to be a strategy for a female in this system to increase her reproductive opportunities. This suggests that either territory quality is inconsequential or the costs of relo cation are prohibitive. Dispersing offspring also may be unable to sel ect certain territories because of the premium placed on acquiring a t erritory, regardless of its quality.