DOI: 10.5061/dryad.6430mr0
title: Data from: Predation risk landscape modifies flying and red squirrel nest site occupancy independently of habitat amount

description: 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.
description: Nest-box occupancy data
 for flying squirrelsData describes occupancy
 (1=precence, 0=absence) of flying squirrels in nest boxes. BCODE= name of
 nest box. ID = a unique combination of box name and census year. Ural owl
 and goshawk columns describe modelled predation risk from these predators
 at the nest box site, see article for methods. h1...h27 refer to different
 land use classes and their combinations as in Table 1 of the research
 article. _200m and _1km means area (square meters) of that habitat within
 200 meters and 1km from nest box, respectively. s (for example h17_200ms)
 refers to standarized amount of that habitat, see
 methods.FlyingSquirrelDataDryad.xlsxNest box occupancy data for red squirrelsData describes nest box occupancy of red squirrels. 1= presence, 0=absence. BCODE= name of the box. ID= unique combination of box name and census year. Goshawk and Ural owl columns describe modelled predation risk from these predators at the nest box site, see methods in research article. h1...h27 refer to land use classes as in Table 1 of the article. _300 and _2500 m refer to the area of each land use class within 300 meters and 2.5 kilometers from the nest box in square meters. Ending 's' (h8_300ms) refers to the standardized area. TimePeriod describes the slightly different detection probability before and since 2006.RedSquirrelDataDryad.xlsxSpruce cone crop dataData describes estimates of Norway spruce cone crop (unit: cones per tree, calculated from trees in research forests) in three different areas, Ullava, Oravainen and Maalahti, surrounding the red squirrel study area in Kauhava, Finland.ConesNearStudyAreaDryad.xlsx