Data from: Predation risk landscape modifies flying and red squirrel nest site occupancy independently of habitat amount

Habitat choice often entails trade-offs between food availability and
predation risk. Understanding the distribution of individuals in space
thus requires that both habitat characteristics and predation risk are
considered simultaneously. Here, we studied the nest box use of two
arboreal squirrels who share preferred habitat with their main predators.
Nocturnal Ural owls (Strix uralensis) decreased occurrence of night-active
flying squirrels (Pteromys volans) and diurnal goshawks (Accipiter
gentilis) that of day-active red squirrels (Sciurus vulgaris).
Unexpectedly, the amount of preferred habitat had no effect on nest box
use, but, surprisingly, both squirrel species seemed to benefit from close
proximity to agricultural fields and red squirrels to urban areas. We
found no evidence of trade-off between settling in a high-quality habitat
and avoiding predators. However, the amount of poor-quality young pine
forests was lower in occupied sites where goshawks were present, possibly
indicating habitat specific predation on red squirrels. The results
suggest that erecting nest boxes for Ural owls should be avoided in the
vicinity of flying squirrel territories in order to conserve the near
threatened flying squirrels. Our results also suggest that flying
squirrels do not always need continuous old forests, and hence the
currently insufficient conservation practices could be improved with
reasonable increases in the areas left untouched around their nests. The
results of this study demonstrate the importance of taking into account
both habitat requirements and predation risk as well as their interactive
effects when modeling the occupancy of threatened animal species and
planning their conservation.