Animals use physiological and behavioral adaptations to maintain constant body temperatures when environmental temperatures are outside of their thermoneutral zone. We define the temperature suitability bounds as the range of temperatures above and below which animals avoid locations because of unfavorable thermal conditions. Temperatures outside the temperature suitability bounds may trigger behavioral responses such as movement to cooler locations. We tested the hypothesis that temperature during late April to August influences resource selection using chestnut‐bellied scaled quail (Callipepla squamata castanogastris) as our study species. We estimated temperature suitability bounds for scaled quail and tested the prediction that ground surface temperature is a better predictor of habitat space use than black globe temperature. We compared models containing ground surface temperature and woody vegetation structure variables to test the hypothesis that including woody vegetation variables improves prediction of relative probability of use. We trapped scaled quail at five different locations in southern Texas. We located quail fitted with necklace‐style transmitters three times/week during 2013–2014. We measured ground surface and black globe temperatures at locations used by scaled quail and at random locations. We estimated percent canopy cover of cacti, subshrubs, and woody plants using 20 × 50 cm Daubenmire frames at each used and random location. We also estimated height and vertical obstruction of woody vegetation. Temperature suitability bounds of scaled were 24–43°C for the ground surface and 23–39°C for black globes. Ground surface temperature was a better predictor of relative probability of use than black globe temperature. Ground surface temperature during the warmest time of day (early afternoon, 13:30–17:29) decreased with increasing vertical obstruction after accounting for the influence of other structural variables. The best model for predicting relative probability of use by scaled quail during the warmest time of day included ground surface temperature and vertical obstruction. Use of microsites where vegetation structure is conducive to cooler temperatures is an important driver of resource selection by scaled quail during the warmest time of day in southern Texas, but availability of thermal refugia appears to be limited.

Non‐native grasses are frequently sown in the southwestern United States for livestock forage and erosion control. These grasses often spread from areas where they are planted and replace native grasses and forbs. We tested the hypothesis that chestnut‐bellied scaled quail (Callipepla squamata castanogastris) avoid locations dominated by non‐native grasses. We trapped scaled quail at 5 different sites in southern Texas, USA, and located quail fitted with necklace‐style transmitters 3 times/week during 2013–2014. We manually delineated plant communities using aerial maps and on‐the‐ground knowledge of the study sites. We examined second‐order (home‐range scale) selection by comparing proportion of the areas of plant communities within 62 scaled quail home ranges (used) paired with random home ranges (available). We examined third‐order (within‐home‐range scale) selection by comparing the composition of bird location (used) and random (available) points based on proportion of points within plant communities. For both home‐range scale and within‐home‐range scale analyses, we used non‐parametric multivariate analysis of variance with 9,999 random permutations. We examined fourth‐order (organism‐centered) selection by measuring vegetation variables at used and available locations and then estimating the relative probability of use of vegetation variables and by estimating continuous selection functions for variables that were influential in determining relative probability of use. Buffelgrass (Pennisetum ciliare) and Old World bluestems (Bothriochloa spp., Dichanthium annulatum and other Dichanthium spp.) comprised 99% (95% CI = 98–100%, n = 143 sites where non‐native plants occurred) of the non‐native grasses in our study areas. Scaled quail avoided non‐native and riparian plant communities at the home‐range and within‐home‐range scales of selection. At the organism‐centered scale of selection, odds of use by scaled quail decreased 28% for every 10% increase in non‐native grass cover and increased 12% for every 10% increase in shrub canopy cover. Scaled quail avoided locations with >10% canopy cover of non‐native grasses. Based on avoidance at 3 scales of selection, dominance of buffelgrass and Old World bluestems degrades habitat for scaled quail. Spread and sowing of non‐native grasses and brush clearing may be partly responsible for declines in scaled quail populations. © 2019 The Wildlife Society.