DOI: 10.5061/dryad.12jm63xzf
title: Data for: Differential landscape use by forest owls two years after a mixed-severity wildfire

description: Owls are important avian predators in forested systems, but little is
 known about landscape use by most forest-adapted owl species in
 environments impacted by mixed-severity wildfire. To better understand
 species-specific patterns of post-wildfire landscape use within an owl
 guild we used passive acoustic monitoring using autonomous recording
 units. The technology is effective for multi-species surveys, especially
 if some species are rare, nocturnal, or difficult to detect by traditional
 means. In 2017 we surveyed the interior and adjacent unburned areas of a
 10,700 ha mixed-severity wildfire that burned in 2015 in southwest Oregon.
 We used occupancy modeling to identify patterns of landscape use by five
 species of forest owls: barred owls (Strix varia), great horned owls (Bubo
 virginianus), western screech-owls (Megascops kennicottii), northern
 pygmy-owls (Glaucidium californicum), and northern saw-whet owls (Aegolius
 acadicus). Our results showed a positive relationship between increasing
 fire severity and probability of use by western screech-owls and a similar
 but somewhat weaker relationship for northern pygmy-owls. Barred owls were
 rarely detected in severely burned areas and their use decreased with
 increased fire severity. We observed generally low landscape use for great
 horned owls, which decreased with increased fire severity and at higher
 elevations. Thus, four out of the five species appeared to use recently
 burned forests at different levels, with only northern saw-whet owls
 showing near-complete avoidance of the burned area. These findings
 increase our understanding of the basic ecology of each species and
 highlight the varied use of burned areas within this community. These
 previously undocumented patterns of landscape use in burned landscapes
 should provide insights to managers and policymakers in the Pacific
 Northwest as climate shifts, and fires may increase in size, frequency,
 and severity.
description: This dataset contains five encounter histories and associated
 environmental covariates for analysis in an occupancy modeling framework.
 Encounter histories for five forest owl species were generated using
 passive acoustic monitoring data summarized to a weekly scale. In the
 binary encounter histories, labeled as such, N/A indicates weeks in which
 stations were not surveyed, zeros represent weeks in which stations were
 surveyed but the species was not detected, and ones indicate weeks in
 which stations were surveyed and the species was detected. Weekly count
 data are also provided; in this case, rather than a one to indicate a
 species was detected during a week, we include the number of vocalizations
 detected within that week. Environmental covariates are
 untransformed values from field measurements or remote sensed data. Site
 covariates are those that do not vary through the season (e.g. fire
 severity), while survey covariates vary within season (e.g. weekly
 temperature) and can be used to model within-season heterogeneity in
 detection probability. Surveys began March 31, 2017.
description: ReadMe file is included with descriptions of missing values and
 definitions of all variables.