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Key habitat for male Strix nebulosa (Great Gray Owls) varies across the diurnal cycle and reflects sex-specific role, data archive

Cite this dataset

Gura, Katherine B. (2024). Key habitat for male Strix nebulosa (Great Gray Owls) varies across the diurnal cycle and reflects sex-specific role, data archive [Dataset]. Dryad. https://doi.org/10.5061/dryad.1g1jwsv50

Abstract

We used GPS tracking and remotely-sensed environmental data to evaluate whether breeding-season habitat selection by adult male Strix nebulosa (Great Gray Owls) (n = 19) varied across diurnal periods (dawn, day, dusk, and night). To address knowledge gaps related to nocturnal habitat, we also evaluated finer-scale, microhabitat selection by male owls at night. Here, we include both the remotely-sensed habitat data and on-the-ground microhabitat data associated with owl locations.  Generally, S. nebulosa are associated with mature forests for nesting and meadows for foraging. Yet, in our study, owls avoided herbaceous wetlands during the day but strongly selected them at dawn, dusk, and at night, indicating context-dependent habitat selection. Moreover, owls avoided dry meadows at all times of the day, suggesting that wet rather than xeric meadows are important for foraging. Owls also preferred nighttime microhabitats that facilitated foraging, such as those with presence of primary prey and open understories dominated by graminoids and forbs. During the daytime, owls preferred higher canopy cover and areas with increased soil moisture, which likely provided suitable roosting habitat. Understanding of habitat preferences across sexes, activity periods, and other contexts can improve the identification and conservation of critical habitat for wildlife.

README: Adult male Strix nebulosa (Great Gray Owl) breeding-season habitat data

https://doi.org/10.5061/dryad.1g1jwsv50

Associated habitat data for used and available locations for GPS-tagged, adult male Strix nebulosa (Great Gray Owls) (n = 19) during the breeding season in northwestern Wyoming between 2018-2021. The data were used to analyze breeding-season habitat selection by adult male S. nebulosa.

Description of the data and file structure

The data include two datasets: remotely-sensed habitat data extracted to the owl locations (Male_GGOW_RemotelySensedHabitat.csv), and on-the-ground microhabitat data collected at a subset of locations used by owls at night (Male_GGOW_Microhabitat.csv).

1) Male_GGOW_RemotelySensedHabitat.csv

This file contains associated habitat data for sites used by adult male Strix nebulosa during the breeding season as well as randomly-selected available sites located within each owl's home range area.  For each location, habitat data were derived from remotely-sensed environmental data and extracted to that location.  The dataset includes an identification for each individual tagged owl ("Individual ID"), date, diurnal period during which the site was used by the owl (dawn, day, dusk, night), and whether the site was used ("1" denotes actual owl location) or simply available to the owl ("0" denotes an available location (within the owl's 95% kernel density estimate for home range).  Associated habitat data for each location includes canopy closure (derived from LandFire 2020), integrated moisture index (a measure of soil moisture) (Evans et al. 2014), land cover classification data (derived from Dewitz and USGS 2021) (land cover was classified or reclassified as: developed, herbaceous, herbaceous wetland, woody wetland; values denote the proportion of area (cells) including and surrounding that location (cell) with the given land cover type), distance to road (kilometers) (derived from USGS road layer for Wyoming), and distance to wetland (kilometers) (based on Dewitz and USGS 2021).

2) Male_GGOW_Microhabitat.csv

This file contains associated microhabitat data for sites used by adult male Strix nebulosa at night during the breeding season as well as available sites.  Data were collected via habitat surveys conducted at the scale of 0.04 hectare fixed radius plots during the breeding season of 2018 and 2019 in northwestern Wyoming.  Dataset columns include an identification for each individual tagged owl ("Individual ID") and whether the site was used (1 denotes actual owl location) or simply available to the owl (0 denotes an available location (within the owl's 95% kernel density estimate for home range). Habitat data include whether or not a habitat edge was present ("Edge"; "1" denotes an edge was present, "0" denotes no edge present), number of canopy stories, distance to habitat edge (meters), distance to meadow (meters), number of coarse woody debris (fallen logs/large fallen tree branches), number of snags (dead standing trees), presence of primary prey sign (Northern Pocket Gopher soil mounds/eskers), trees per acre, basal area, basal area of coniferous species, basal area of deciduous species, average canopy closure, dominant habitat type (values are edge (more than one habitat type present in plot; "EDG"), aspen ("AS"), mixed aspen-conifer ("MAC"), lodgepole pine forest ("LP"), mixed conifers ("MC"), meadow ("MEAD"), sagebrush ("SAG"), sub-alpine fir ("SF"), willow ("WILL"), and wet meadow ("WME")), and dominant understory type (value are grass, forbs, shrubs, saplings; for each column containing an understory type, "1" denotes that understory type present, "0" denotes that understory type was not present).

Sharing/Access information

The data underlying this article are available at the Dryad Digital Repository.

References

Dewitz, J., and U.S. Geological Survey. 2021. National Land Cover Database (NLCD) 2019 Products (ver. 2.0, June 2021): U.S. Geological Survey data release, https://doi.org/10.5066/P9KZCM54.

Evans J.S., J. Oakleaf, S.A. Cushman, and D. Theobald. 2014. An ArcGIS Toolbox for Surface Gradient and Geomorphometric Modeling, version 2.0-0. Accessed: 2022 Sept.

Landfire. Landfire Existing Vegetation Cover layer. 2020a. U.S. Department of Interior, Geological Survey, and U.S. Department of Agriculture. Available: http:landfire.cr.usgs.gov/viewer/ [2022, September 1].

Methods

Associated habitat data for used and available locations for GPS-tagged, adult male Strix nebulosa (Great Gray Owls) (n = 19) during the breeding season in northwestern Wyoming between 2018-2021.  Habitat attributes were derived from remotely-sensed environmental data and exracted to owl locations.  Available locations were generated within 95% Kernel Density Estimate (KDE) areas.  A subset of these data include microhabitat attributes measured via on-the-ground surveys.  These sites were selected via a stratified random sampling design, in which we selected approximately 30 nighttime used locations, but no more than one location used per night per individual. Paired availale sites were selected from within 95% KDE areas.

Funding

Wyoming Game and Fish Department