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Areas occupied by white-tailed prairie dogs (WTPD; Cynomys leucurus) and Gunnison's prairie dogs (GPD; C. gunnisoni) are not well-known in Colorado (USA) and elsewhere. Suitable methodology for monitoring changes in populations of WTPD and GPD over broad areas also has not been well established. We evaluated occupancy modeling methodology to establish baseline occupancy rates for WTPD and GPD in Colorado. We estimated that WTPD occupied 24.1% (SE = 12.8) of 47,710 0.25-km2 plots and GPD occupied 7.5% (SE = 1.3) of 158,225 0.25-km2 plots in Colorado during 2004 and 2005. Areas reported as colonies in the Colorado Division of Wildlife's database were not good predictors of WTPD and GPD occupancy. Occupancy rates were...
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Data set resulting from monitoring the behavior of snakes (n = 62) that had been feed a standardized large meal with transmitter, proportional to their body mass, to make direct comparisons to a control group of snakes that had not been fed a meal (only the transmitter). Transmitters were equipped with a two-position switch that changes pulse rate when the body position of the animal changes more than 10 degrees from the switch's preset orientation. Changes in pulse rate serve as a proxy measurement for snake activity, under the logic that a relatively stationary/sedentary snake would cause the transmitter to tip less frequently that an actively moving/foraging snake would. The experiment took place in the U.S....
Feral burros (Equus asinus) and horses (E. ferus caballus) inhabiting public land in the western United States are intended to be managed at population levels established to promote a thriving, natural ecological balance. Like many large ungulate populations, management agencies employ aerial surveys to obtain estimates of horse and burro population sizes. Double-observer sightability (MDS) models perform well for estimating feral horse abundances, yet the effectiveness of these models for use in burro populations is less understood and may be different due to the smaller size, stoic behavior, and cryptic pelage of burros. These models help minimize detection bias, yet bias can be further reduced with models that...
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This dataset contains detection-nondetection data for territorial pairs of Golden Eagles at survey sites randomly selected from a grid of equal-sized (13.9 km2) hexagonal sample cells overlaid across the region of interest in Coastal Southern California during 2016 and 2017. We partitioned surveys within seasons based on approximate transition dates for stages in the breeding cycle of golden eagles in the study region: courtship (15 Dec-28 Feb), incubation (1 Mar-30 Apr), nestling (1 May-15 Jun), and the fledging-dependency period (16 June-Jul 30), totaling 4 possible sampling periods per year. This dataset also describes the proportion of land-cover types from four general categories (urban, open grassland, scrub...
These data represent occupancy estimates for western bumble bee across the western continental United States and the spatial variation in detection probabilities that occur during bumble bee surveys. This product contains five raster layers (appearing as separate bands in a multi-band raster). The first two bands represent the predicted occupancy of western bumble bee in 1998 and 2018. We modeled western bumble bee occupancy as a function of: latitude, longitude, elevation, year, and land cover. The last three bands represent the spatial variation in detection probabilities predicted to occur for surveys conducted across the western United States on three dates (May 15, July 15, and September 15). We modeled detection...
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Occupancy models provide a reliable method of estimating species distributions while accounting for imperfect detectability. The cost of accounting for false absences is that detection and nondetection surveys typically require repeated visits to a site or multiple-observer techniques. More efficient methods of collecting data to estimate detection probabilities would allow additional sites to be surveyed for the same amount of effort, which would support more precise estimation of covariate effects to improve inference about underlying ecological processes. Time-to-detection surveys allow the estimation of detection probability based on a single site visit by one observer, and therefore might be an efficient technique...
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This dataset contains count and detection-nondetection data of Barred Owls from 106 historical breeding territories of Northern Spotted Owl territories (i.e. sites) in the Oregon Coast Ranges from 1995 to 2016. Data collected from 1995 to 2014 are partitioned into 2-week periods from 1 March – 31 August each year, totaling 12 possible sampling periods per year. Data collected from 2015 and 2016 are partitioned into 2-month periods from 1 March – 31 August, totaling 3 possible sampling periods each year. This dataset also describes the proportion of total area surveyed per site per sampling period in 2015 and 2016, as well as the proportion of each site with older coniferous forest in each year (1995 – 2016).


    map background search result map search result map Count and detection-nondetection survey data of Barred Owls (Strix varia) in historical breeding territories of Northern Spotted Owls (Strix occidentalis caurina) in the Oregon Coast Ranges, 1995-2016 Time to detection data for Point Reyes pond-breeding amphibians, 2017 Brown Treesnake morphological and behavioral differences following ingestion of large meals, 2015 Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018 Detections of bison from helicopter and aerial thermal infrared imagery in Grand Canyon National Park, 2019-2021 Detections of burros from helicopter aerial surveys in the southwestern US, 2016-2018 Detection/non-detection data on territorial pairs of golden eagles in coastal southern California, 2016-2017 Brown Treesnake morphological and behavioral differences following ingestion of large meals, 2015 Time to detection data for Point Reyes pond-breeding amphibians, 2017 Count and detection-nondetection survey data of Barred Owls (Strix varia) in historical breeding territories of Northern Spotted Owls (Strix occidentalis caurina) in the Oregon Coast Ranges, 1995-2016 Detections of bison from helicopter and aerial thermal infrared imagery in Grand Canyon National Park, 2019-2021 Detection/non-detection data on territorial pairs of golden eagles in coastal southern California, 2016-2017 Detections of burros from helicopter aerial surveys in the southwestern US, 2016-2018 Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018