Declines in northern bobwhite (Colinus virginianus) populations have led landowners in Texas, USA, to develop various management strategies to combat waning abundance. One common management strategy is to provide supplemental feed to bobwhites, despite the paucity of information regarding the effects of supplemental feed on bobwhite space use and survival. We examined survival and home range of bobwhites using the technique of spreading supplemental feed into roadside vegetation in the Texas Rolling Plains. The study sites were divided into 8 (404.6-ha) units randomly designated as treatment (feed provided) or control (feed withheld). Treatment and control units were rotated during the second field season to minimize potential habitat bias. Treatment units received approximately 69.1 kg/km of milo (Sorghum bicolor) twice per month. We captured and radiomarked 197 female bobwhites (82 treatment [48: 2010-2011; 34: 2011-2012], 115 control [64: 2010-2011; 51: 2011-2012]) from autumn 2010 to spring 2012. Females were monitored for location and survival with radiotelemetry 3-4 times/week. Average home-range size was similar on control and treatment units (47.6 ha [8.7 SE] and 46.2 ha [10.3 SE], respectively). We estimated survival rate with the nest survival model in Program MARK. We observed an increase in survival rate on treatment units compared with control units, regardless of year or environmental conditions. Our results suggest that distributing supplemental feed into roadside vegetation positively influences bobwhite survival with no reduction in home range size. Ó 2015 The Wildlife Society.
Serum concentrations of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST) were measured in captive and wild mallards (Anas platyrhynchos) as indicators of muscle damage. Baseline values for both enzymes were determined from six captive male mallards. During winter 1990 to 1991, six diets (including controls) representative of food available in the Mississippi alluvial valley were fed to captive female mallards housed in an outdoor aviary at the White River National Wildlife Refuge, Arkansas County, Arkansas (USA). Controlled handling of penned mallards resulted in elevated serum CK (means = 1,352 IU/liter; SD = 1,212) and AST (means = 101 IU/liter; SD = 95) concentrations consistent with myopathies. These serum enzyme elevations were not affected (P > 0.3) by dietary selenium concentrations in the six diets or by energy malnutrition suffered by birds fed soybeans. Capture of wild mallards with an entanglement type rocket net resulted in serum CK and AST concentrations (means = 12,035 and 330 IU/liter; SD = 8,125 and 171, respectively) that were higher (P < 0.001) than those reported after capture with an enveloping type rocket net. Baseline values, controlled handling values, and entanglement rocket net values for serum CK and AST all differed (P < 0.0001).
We tested the hypothesis that exposure of Northern Bobwhites (Colinus virginianus) to acute temperature stressors impairs their immune-system function and resistance to disease. Birds were randomly assigned to either a thermoneutral (constant 21øC), coldstress (cycled from 3.6 to-20øC over 24 h), or heat-stress (cycled from 30.8 to 39.0øC over 24 h) treatment for four consecutive days. Immunocompetence of each bird was evaluated on day 5 using a panel of assays, including a measure of resistance to a Pasteurella multocida Type 3 challenge. Neither thermal stressor had an influence on spleen mass or measures of cellmediated and humoral immunity. Disease resistance of Northern Bobwhites to P. multocida was not influenced by heat stress but increased following cold stress. Cold stress may have increased the activity of phagocytic leukocytes, which are important in resistance of birds to bacterial pathogens. A concomitant decrease in lymphocyte numbers suggested that resistance to vital pathogens was compromised during cold stress.
Home range is expected to vary with ecological conditions to minimize size while still meeting the biological needs of the individual animal. Understanding the determinants of variation in home range size can be important when trying to manage or control an invasive species. Wild pigs (Sus scrofa) have been introduced throughout the globe and cause notable damage to native ecosystems. We quantified relationships of wild pig home range with environmental conditions across varying spatial and temporal scales to better understand population space use in areas invaded by wild pigs during March 2011 to August 2012 in Kent County, Texas, USA. We used mixed‐effects linear‐regression models to assess how allometric effects of body size and environmental variables (temp, elevation, latitude, and rainfall) could be used to predict home range size at a local scale. We then used general linear models with published data from 31 studies from the species’ global distribution to investigate the efficacy of environmental parameters as home range predictors. On account of either temporal or incomplete variables, home range was not well‐predicted at a local scale. Across their global distribution, the top ranked model included all 4 variables with home range positively associated with temperature, elevation, and latitude, but negatively associated with rainfall. Use of the global model represents a cost‐efficient way to estimate home ranges to control or eradicate wild pig populations. This information can be valuable for management of both established and newly introduced populations for population estimation and trapping density. © 2016 The Wildlife Society.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.