The theory of habitat selection predicts that organisms should use habitat that maximizes their fitness. The cooperatively breeding Rufous Treecreeper, Climacteris rufa, exhibits non-random habitat use at a number of spatial scales. By assessing correlative relationships between nest-site use and nest success, and territory use and reproductive success and survival, it was determined whether non-random use of habitat yields fitness benefits. It was also determined whether breeding group size contributed significantly to fitness once differences in territory quality had been considered. Structural characteristics of nest sites that were positively correlated with the probability of a site being used had no relationship with nest success. This result probably reflects the relatively unrestricted access to an abundance of suitable nest sites in the study area. Habitat traits that predicted territory use by treecreepers were positively correlated with a number of fitness measures. They were also positively correlated with breeding group size and provisioning rate to nestlings, which in turn were correlated with fitness. However, group size was not significantly related to any measure of fitness, except primary male survival, once territory quality had been considered. The quality of territories occupied by Rufous Treecreepers appeared to be a significant factor for breeding group fitness.