Relative value of a nest box, sand floor and extra space during the breeding season in adult blue fox males

We measured how much adult blue fox males value access to a nest box and sand floor enrichments while a platform and activity object are available simultaneously. Ten blue fox males were solitary housed in test apparatuses with permanent access to a platform and wooden block (activity object) during the breeding season. The foxes could gain access to either a nest box, a sand floor or to empty space by passing through a weighted one-way door on workloads increasing every 24 h. The foxes’ behaviour was recorded on workloads of 0, 1.5, 3, and 5 kg of extra weight. The foxes were highly active during the study. As the workload increased, the number of visits and the time spent in the cage with the resource decreased. This trend was most evident in the case of the sand floor. However, the workload did not affect the actual time spent interacting with the nest box or sand floor. The foxes utilised the sand floor and nest box more than the permanently available platform and wooden block. The present results suggest that during the breeding season, adult blue fox males are highly motivated to explore the accessible area and they value access to both a sand floor and nest box.