Microclimate Versus Predation Risk in Roost and Covert Selection by Bobwhites

Hiller, Tim L.; Guthery, Fred S.

doi:10.2193/0022-541x(2005)069<0140:mvprir>2.0.co;2

Cited by 26 publications

(40 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because understanding roosting coverts was not an initial objective for this study, we did not collect random locations within the landscape to compare to the nocturnal locations at which we found bobwhites. However, our findings are consistent with the findings of similar conditions at bobwhite roosting sites by Klimstra and Ziccardi () and Hiller and Guthery () where bobwhites were observed to roost in sparsely vegetated areas. Tillman () studied nocturnal roosting and anti‐predation behavior of gray partridges ( Perdix perdix ) and reasoned that choosing exposed roosting locations was a form of predator avoidance behavior that highlighted the importance of unobstructed clear flight paths for escape if approached by a predator.…”

Section: Discussionsupporting

confidence: 93%

Northern bobwhite predator avoidance behavior in response to varying types of threat

Perkins¹,

Boal

Rollins

et al. 2014

Jour. Wild. Mgmt.

View full text Add to dashboard Cite

The flight behavior and cover use of northern bobwhite (Colinus virginianus) have been examined in several studies, but the current data lack quantitative measures of how bobwhites respond to natural threats. We examined aspects of bobwhite behavior in response to 4 threat categories: researcher, hunter, raptor, and mammal. We found that bobwhite flight distance is best predicted by threat type and covey size, and bobwhite flight speed is best predicted by threat type. Bobwhites flushed by the hunter threat and the raptor threat selected for significantly taller obstruction at landing sites than was randomly available, with average heights of 6.2 cm taller (P = 0.034), and 38.1 cm taller (P < 0.001), respectively. Raptor‐flushed bobwhites also selected for significantly denser shrub cover (42.2%, P < 0.001) and a lower angle of obstruction (70.4°, P < 0.001) at landing points than was randomly available. In the process of data collection, we also observed bobwhite roost locations have lower visual height obstruction (7.3 cm, P = 0.03), lower shrub intercept (10.1%, P = 0.02), and greater angles of obstruction (18.5°, P = 0.005) than bobwhite diurnal locations; this may facilitate escape from nocturnal mammalian predators. Our results suggest that bobwhite escape strategies and cover use vary among threat types. These results support current management recommendations of creating a patchwork of vegetation covers for bobwhites but also suggest how a more complete understanding of bobwhite behavior would improve management and conservation efforts. © 2014 The Wildlife Society.

show abstract

Section: Discussionsupporting

confidence: 93%

Northern bobwhite predator avoidance behavior in response to varying types of threat

Perkins¹,

Boal

Rollins

et al. 2014

Jour. Wild. Mgmt.

View full text Add to dashboard Cite

show abstract

“…However, it is difficult to disentangle the use of woody cover during midday for thermal cover from avoidance of avian predators (Guthery et al. , Hiller and Guthery ). It is possible that cover for predator avoidance and cover for thermal refugia act in synchrony and management should focus on sufficient cover for both (Guthery et al.…”

Section: Discussionmentioning

confidence: 99%

“…Ground surface temperature has been largely ignored in bobwhite research (Guthery et al. , Hiller and Guthery , Carroll et al. ).…”

Section: Introductionmentioning

confidence: 99%

Ground surface vs. black globe temperature in northern bobwhite resource selection

et al. 2018

View full text Add to dashboard Cite

Understanding thermal ecology of endotherms is becoming increasingly important with predicted increases in temperature associated with climate change. Patterns of resource selection may depend in part on temperature thresholds outside which animals avoid warmer or cooler temperatures. During summer, northern bobwhites (Colinus virginianus; hereafter bobwhite) in semiarid areas often exist at the limits of their thermal tolerance. We sought to determine (1) selection bounds for black globe and ground surface temperatures, (2) whether ground surface temperature is a better predictor of the thermal environment used by bobwhites than black globe temperature, and (3) how time of the day influences thermal resource use. We radio‐marked 40 bobwhites and located them two to three times a week from April to September in 2014–2016. At each location, we measured ground surface and black globe temperatures at the bird location and at a location 20 m away in a random direction. We calculated continuous selection functions to estimate bounds of thermal characteristics suitable for bobwhites. We used generalized linear models to determine times of day bobwhites select cooler microclimates. Finally, we used case‐controlled logistic regression models to generate thermal resource selection functions. We compared models that included ground surface temperature, black globe temperature, and an index created from both variables with principal component analysis and selected the best model based on Akaike's information criterion adjusted for sample size (AICc) and log‐evidence ratios. Upper and lower selection bounds for black globe temperature and ground surface temperature were 24.5–42.5°C and 23.0–39.5°C, respectively. A principal component of black globe combined with ground surface temperature was a better predictor of bobwhite resource selection than either black globe temperature or ground surface temperature alone. In early afternoon (13:01–17:30 hours) during August, bobwhite locations had 13°C cooler black globe temperatures and 18°C cooler ground surface temperatures than random locations. Availability of thermally usable coverts (woody plant thickets) may be a limiting factor for bobwhites in the study area based on the findings that mean ground surface and black globe temperatures at used locations were close to the upper bounds for use in late summer during the middle of the day.

show abstract

“…We also centered a 0.5 m 2 quadrat (modified from Daubenmire, ) over the estimated bird location or random location to estimate percent bare ground, litter, grass, forb, and woody cover. Vegetation height at each sampling point was classified into categories of <1 m, ≥1‐ <2 m, and ≥2 m given that bobwhites have been shown to utilize varying vegetation heights throughout the day at adult (Hiller & Guthery, ) and brood locations (Carroll, Davis, Elmore, Fuhlendorf, & Thacker, ). To better inform the potential management of thermal space and because thermal refuge selection by birds can be species specific (Martin et al., ), we also we recorded the dominant species at each location (e.g., hybrid shinnery oak, sand plum, etc.…”

Section: Methodsmentioning

confidence: 99%

Using a historic drought and high‐heat event to validate thermal exposure predictions for ground‐dwelling birds

Carroll

Davis

Elmore

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

Deviations from typical environmental conditions can provide insight into how organisms may respond to future weather extremes predicted by climate modeling. During an episodic and multimonth heat wave event (i.e., ambient temperature up to 43.4°C), we studied the thermal ecology of a ground‐dwelling bird species in Western Oklahoma, USA. Specifically, we measured black bulb temperature (T bb) and vegetation parameters at northern bobwhite (Colinus virginianus; hereafter bobwhite) adult and brood locations as well as at stratified random points in the study area. On the hottest days (i.e., ≥39°C), adults and broods obtained thermal refuge using tall woody cover that remained on average up to 16.51°C cooler than random sites on the landscape which reached >57°C. We also found that refuge sites used by bobwhites moderated thermal conditions by more than twofold compared to stratified random sites on the landscape but that T bb commonly exceeded thermal stress thresholds for bobwhites (39°C) for several hours of the day within thermal refuges. The serendipitous high heat conditions captured in our study represent extreme heat for our study region as well as thermal stress for our study species, and subsequently allowed us to assess ground‐dwelling bird responses to temperatures that are predicted to become more common in the future. Our findings confirm the critical importance of tall woody cover for moderating temperatures and functioning as important islands of thermal refuge for ground‐dwelling birds, especially during extreme heat. However, the potential for extreme heat loads within thermal refuges that we observed (albeit much less extreme than the landscape) indicates that the functionality of tall woody cover to mitigate heat extremes may be increasingly limited in the future, thereby reinforcing predictions that climate change represents a clear and present danger for these species.

show abstract

Microclimate Versus Predation Risk in Roost and Covert Selection by Bobwhites

Cited by 26 publications

References 18 publications

Northern bobwhite predator avoidance behavior in response to varying types of threat

Northern bobwhite predator avoidance behavior in response to varying types of threat

Ground surface vs. black globe temperature in northern bobwhite resource selection

Using a historic drought and high‐heat event to validate thermal exposure predictions for ground‐dwelling birds

Contact Info

Product

Resources

About