Behavior-specific occupancy patterns of Pinyon Jays (Gymnorhinus cyanocephalus) in three Great Basin study areas and significance for pinyon-juniper woodland management

Abstract

AbstractThe Pinyon Jay is a highly-social, year-round inhabitant of pinyon-juniper woodlands in the western United States. Range-wide, Pinyon Jays have declined ~ 3 - 4% per year for at least the last half-century. At the same time, large acreages of pinyon-juniper woodland have been removed or thinned to improve habitat for Greater Sage-Grouse or other game species across much of the Great Basin, which is home to nearly half of the global population of Pinyon Jays. Occupancy patterns and habitat use of Pinyon Jays have not been well characterized across much of the species range, and obtaining this information is necessary for better understanding the causes of ongoing declines and determining useful conservation strategies. Our goal of this study was to identify the characteristics of areas used by Pinyon Jays for several critical life history components and to thereby facilitate the inclusion of Pinyon Jay conservation measures in the design of vegetation management projects. To accomplish this, we studied Pinyon Jays in three widely separated study areas using radio telemetry and direct observation, and measured key attributes of their locations and a separate set of randomly-selected control sites using the U. S. Forest Services Forest Inventory Analysis protocol. Data visualizations, non-metric dimension scaling ordinations, and logistic regressions of the resulting data indicated that Pinyon Jay occupancy was concentrated in a distinct subset of available pinyon-juniper woodland habitat, and further that Pinyon Jays used different habitats, arrayed along elevational and tree-cover gradients, for seed caching, foraging, and nesting. Caching was concentrated in low-elevation, relatively flat areas with low tree cover; foraging occurred at slightly higher elevations with moderate tree cover, and nesting was concentrated in somewhat higher areas with greater tree cover and higher stand density. All three of these Pinyon Jay behavior types were highly concentrated within the lower-elevation band of pinyon-juniper woodland close to the woodland-shrubland ecotone. Because woodland removal projects in the Great Basin are often concentrated in these same areas, it is critical to incorporate conservation measures informed by Pinyon Jay occupancy patterns into existing woodland management paradigms, protocols, and practices.