Thesis

Winter survival and resource selection of GPS equipped northern bobwhite in the Rolling Plains of Texas

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Abstract

Assessment of northern bobwhite (Colinus virginianus) habitat management practices is often expensive and labor intensive, as is the tracking of bobwhites to measure resource use and reaction to management or experimental treatment. Traditional solutions to both these problems (e.g., aerial and satellite imagery and Very High Frequency tracking tags [VHF]) each have issues including lengthy return times, coarse scale, high labor inputs, and possible observer bias. Northern bobwhite researchers have recently begun to use solar powered Global Positioning System tags (GPS) to acquire fine scale northern bobwhite location data. I first compared differences in daily survival probabilities between northern bobwhite wearing typical VHF tags and GPS tags in the Rolling Plains of Texas from 2017 – 2019. I estimated apparent survival for northern bobwhites (n = 112) during the non-breeding season, 1 October – 31 March. When possible, I paired northern bobwhites of similar mass in the same coveys with both transmitter types and used radio telemetry to determine fates of radio-tagged northern bobwhites. I developed 3 a priori models using the nest survival model in Program MARK to estimate daily survival probabilities (DSP) for both transmitter pairings as well as to explore the relationship between survival and quail mass. Northern bobwhites fitted with GPS backpacks had 0.03 lower daily survival probabilities compared to VHF necklace-equipped northern bobwhites with non-overlapping 95% confidence intervals (GPS DSP = 0.95; SE = 0.008; VHF DSP = 0.98; SE = 0.003). Next, I evaluated the efficacy of using an Unmanned Aerial Vehicle (UAV) paired with GPS tag data to assess northern bobwhite habitat. I used an UAV to collect high resolution georeferenced imagery of the home ranges of a subset of my study animals (n = 20). These images were developed into a Land Use Land Cover map to quantify the cover found in the home ranges of those northern bobwhite and to estimate their resource selection based on the data collected from the GPS tags. I was able to classify northern bobwhite cover into typical canopy classes (bare, shrub, grass; mean overall accuracy = 91.47% ± 2.57; mean Kappa = 0.88 ± 0.03). I observed no significant 2nd or 3rd order habitat selection during the first winter. In the second winter I observed selection for shrubs (Wi = 1.1 ± 0.64) and against grasses (Wi = 0.59 ± 0.21). My results suggest caution is warranted in selection of new sensor and harness pairings, and that while solar GPS tags may not affect movement-based questions, their use may bias survival related questions. Additionally, UAVs may fit a needed role in timely data collection, but their use should be matched with the appropriate spatial and temporal scale needed to answer the specific research question.

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The Rolling Plains have historically provided some of the best opportunities to hunt northern bobwhite (Colinus virginianus) populations anywhere. Historically, scaled quail (Callipepla squamata) have been common to abundant over much of the Rolling Plains, but the populations decreased dramatically in the late 1980s and have been slow to reclaim their historic range. Copyright © 2007 by Leonard Alfred Brennan Manufactured in the United States of America All rights reserved.
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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. © 2015 The Wildlife Society.
Article
To better understand the reproductive mechanisms that enable northern bobwhite (Colinus virginianus) to recover from high annual mortality, we studied the reproductive strategies, success, and mating systems of 321 radio-marked bobwhite in northern Missouri during 1990-92. Seventy-four female and 43 male bobwhite incubated 159 nests. Females exhibited apparent monogamy during 60% of nesting attempts and apparent polyandry during 40%. Over the entire nesting season, 71% of females were polyandrous. Of those birds alive 15 April (n = 112 F, n = 148 M), 40.2% of females and 13.5% of males successfully hatched ≥1 nest. Seventy-four percent of females (n = 42) and 26% of males (n = 50) surviving until 1 September successfully hatched ≥1 nest. Nesting females that survived the nesting period incubated a mean of 1.8 nests (SE = 0.13), and males incubated 1.0 nests (SE = 0.04). Of those birds that failed on an initial nesting attempt, 57.9% of females (n = 38) and 2 of 23 males incubated ≥1 renest. Of those females that were successful on their initial nesting attempt, 25.7% attempted second nests. Female first nests represented 45.9%, female renests 20.1%, female double-clutch attempts 5.7%, and male-incubated nests 28.3% of all nests located. Nest survival was 43.7% (SE = 3.9). The reproductive system of northern bobwhite enables recovery from low annual survival or periodic catastrophic declines and may be an adaptation to fluctuating resources in ephemeral, dynamic habitats.
Article
We recorded recovery rates for 300 adult female ring-necked pheasants (Phasianus colchicus) and 150 juveniles (82 M, 68 F) marked with 2 different dummy radio tags or leg bands. Birds with backpack tags in all age and sex categories disappeared more quickly and were recovered by shooting or trapping less often than birds with necklace tags or with leg bands (P < 0.05 for juv and ad F). Survival was not affected by weight of necklaces (15 or 25 g) or by the color of the backpacks (white or brown). Necklace radio tags, at 2-3% of body weight, are more suitable than backpacks for studies of pheasant survival.
Article
We conducted a pen study to determine the effects of radio tags on northern bobwhite (Colinus virginianus) body composition and survival. Two groups of 50 birds were fitted with radio tags using two attachment styles (backpack or bib); a third group of 50 birds with no radio tags served as controls. During 12 wk, we monitored weekly live body mass and lipid mass and noted whether tags were attached properly. After 12 wk, the birds were sacrificed and total body lipids, lean mass and water mass were determined. Body and lipid mass did not vary among groups before we attached tags. After 12 wk, tagged birds had significantly lower body weights and less lipid mass than controls. Birds with bibs had significantly lower survival rates than birds with backpacks. Most of the tagged birds (54%) experienced problems with their harnesses. Neither harness design was clearly superior because both designs had a high incidence of problems. Loss of lipids can reduce survival by reducing energy reserves and lower nesting success by reducing clutch size or delaying onset of ovulation. Harness problems may increase vulnerability of tagged birds to predation. Thus, estimates of survival and nesting effort obtained with radio-tagged quail may be biased. Alternative attachment designs should be evaluated, and alternatives to radio tags that are less stressful to the birds (e.g., whistle counts) should be favored when possible.
Article
During 1987 and 1988, we tested the hypotheses that radio transmitter size (14 vs. 18-22 g) and signal strength (1-stage vs. 2-stage) had no effect on estimates of survival, movement, or home range of 54 female greater prairie-chickens (Tympanuchus cupido). Birds (n = 33) wearing heavier 2-stage solar transmitters, with twice the reflective surface, had lower (P = 0.08) estimated annual survival than birds (n = 21) wearing the lighter transmitter. In 2 of 3 seasons, estimates of daily movements, within-day movements, and seasonal ranges were larger (P < 0.09) for birds equipped with the more powerful 2-stage transmitters. Differences in estimated movements and home range did not represent true differences because long distance movements were more likely to be detected for birds wearing 2-stage units than for those equipped with 1-stage transmitters.
Article
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A leading text for undergraduate- and graduate-level courses, this book introduces widely used forms of remote sensing imagery and their applications in plant sciences, hydrology, earth sciences, and land use analysis. The text provides comprehensive coverage of principal topics and serves as a framework for organizing the vast amount of remote sensing information available on the Web. Featuring case studies and review questions, the book's 4 sections and 21 chapters are carefully designed as independent units that instructors can select from as needed for their courses. Illustrations include 29 color plates and over 400 black-and-white figures. New to This Edition Reflects significant technological and methodological advances. Chapter on aerial photography now emphasizes digital rather than analog systems. Updated discussions of accuracy assessment, multitemporal change detection, and digital preprocessing. Links to recommended online videos and tutorials.
Article
We compared the uses and definitions of habitat-related terms in 50 articles from 1980 to 1994 to operational definitions we derived from the literature. Only 9 (18%) of the arti- cles we reviewed defined and used habitat-related terms consistently and according to our definitions of the terms. Forty-seven articles used the term "habitat;" however, it was only defined and used consistent with our definition in 5 articles (11%) and was confused with vegetation association or defined incompletely in 42 papers (89%). "Habitat type" was the term most commonly used incorrectly; 16 of 17 times (94%) it was used to indi- cate vegetation association, but habitat and vegetation association are not synonymous. Authors did not provide definitions for habitat use, selection, preference, or availability 23 of 28 times (82%). We concluded that habitat terminology was used vaguely in 82% of the articles we reviewed. This distorts our communication with scientists in other dis- ciplines and alienates the public because we give ambiguous, indefinite, and unstandard- ized answers to ecological questions in public and legal situations. Scientists should de- fine and use habitat terminology operationally, so that the concepts are measurable and accurate. We must take the challenge to standardize terminology seriously, so that we can make meaningful statements to advance science.
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Historical background, fundamental concepts, statistical considerations and a case study emphasize the need for absolute precision in applying remotely sensed data. This book is a complete guide to assessing the accuracy of maps generated from remotely sensed data.
Article
Many rangelands in the southwestern United States provide quality habitat for Northern Bobwhites (Colinus virginianus). These same habitats are frequently managed for livestock production and thus are subjected to various brush management practices that are meant to enhance forage production. Bobwhites rely on woody cover for food, thermal and loafing cover, and protection from avian predators. Implementing brush management practices that reflect bobwhite requirements is important for managing usable space and viable populations. We described the structural vegetative characteristics associated with bobwhite locations and random locations on native rangelands in the upper Rolling Plains of Texas that are dominated by honey mesquite (Prosopis glandulosa) and managed with aerial herbicide and prescribed fire. We also used binary logistic regression to model habitat selection; the initial model was built using 67% of the data (n = 179 used-random paired points) and then validated using the remaining 33% of the data (n = 88 used-random paired points). Locations used by bobwhites had significantly larger mean values of percent brush canopy cover, visual obstruction, and angle of obstruction than did random locations; random locations had a greater mean value of percent bare ground than locations used by bobwhites. The resulting logistic regression model contained only the angle of obstruction; the model had an 80% probability of correctly classifying used and random locations based on the area under the receiver operating curve (ROC). The model maintained a high classification probability when applied to the smaller validation data set, with an area under the ROC of 0.78.
Article
Having become suspicious of telemetry-based survival rates reported for northern bobwhites (Colinus virginianus), we surveyed the published record to determine whether reported survival rates were consistent with empirical expectations of production, for which there exists a vast database. If the production (juvenile/adult) required to stabilize a population at a reported or inferred annual survival rate was ≤7, we deemed the reported survival rate reasonable; otherwise, we deemed it not reasonable. We obtained 58 estimates of survival rates for unique points in space and time; 83% of these were not reasonable (apparently biased low). These results and supporting information strongly suggest (but do not necessarily prove) that radio packages (harness, transmitter, antenna) somehow handicap bobwhites. We recommend that researchers be extremely skeptical of telemetry data, plan telemetry studies such that independent data on population performance are available for comparison with telemetry estimates, and discuss the demographic implications of telemetry estimates. We also suggest that radiotelemetry might not always be appropriate for a given research question and that alternative methods be employed whenever possible.
Article
Radiotelemetry has been widely used in northern bobwhite (Colinus virginianus) research to estimate survival rates and other demographic parameters. Biologists have used this knowledge to study bobwhite ecology, develop management theory, and base management actions. We tested the assumption that radiotransmitters do not bias survival rates of bobwhites by comparing survival rates of banded bobwhites with and without radiotransmitters on Tall Timbers Research Station (TTRS) from 1999 to 2004. We used Burnham's model in Program MARK and model-selection procedures to determine relative importance of year, gender, and radiotagged status on annual survival rates and recovery processes. Three plausible models (relative quasi-likelihood Akaike's Information Criterion [ΔQAICc] < 3) included year dependence in survival and an additive effect of gender but no radiotransmitter effect. Models including a radiotransmitter effect in survival were >8 ΔQAICc from the top models, had low Akaike model weights (wi < 0.007), and low importance weight (S̀wi(radio) = 0.01). We also compared band—recapture survival estimates from the QAICc minimizing model to staggered entry Kaplan—Meier (KM) survival estimates from 2000 to 2003. Annual KM survival estimates of male and female bobwhites were within the 95% confidence interval of band—recapture estimates in 7 of 8 comparisons. We conclude that radiotelemetry is a reliable technique for determining bobwhite survival. Managers should view information from properly conducted telemetry research as reliable and useful for management.
Article
Radiotelemetry has become an important and frequently used tool in wildlife research. Inferences drawn from radiotelemetry data depend on the assumption that the radiotransmitters are not influencing parameter(s) of interest. An article by Guthery and Lusk (2004) in the Wildlife Society Bulletin questioned the validity of this assumption for estimating survival rates of northern bobwhites (Colinus virginianus) using radiotelemetry data. In this evaluation, we address technical and philosophical flaws in Guthery and Lusk's (2004) critique of northern bobwhite studies utilizing radiotelemetry. They concluded that biologists should be skeptical of radiotelemetry studies and they advised researchers to design studies to address potential biases caused by radiotransmitters using independent data. Although we agree that researchers are responsible for testing key assumptions of their techniques, we believe Guthery and Lusk's (2004) conclusions were not well supported and were based on tenuous assumptions. Guthery and Lusk (2004) calculated the level of productivity (given as a fall age ratio) required to balance a simple population model that contained published estimates of annual survival and assumed an annual finite population growth rate of 1.0. We review their population model and show that the relationship between an annual survival rate and fall age ratio is nonlinear. This nonlinearity can lead to biased estimates of a fall age ratio, especially at lower values of annual survival. We also question the validity of using fall age ratios as an estimator of productivity. Further, we suggest that this assessment of a radiotransmitter effect from a survival rate itself is not appropriate. This rate can be depressed (or elevated) for a variety of reasons not related to the influence of radiotransmitters. In addition, Guthery and Lusk (2004) assumed that daily survival rates (as calculated from both annual and seasonal published estimates) were constant throughout the year; thus, they scaled daily survival rates from seasonal to annual estimates. Further, their meta-analysis was hindered by temporal pseudoreplication and a lack of independence among the observations used in the analysis. We conclude the weight of the evidence presented by Guthery and Lusk (2004) is not as strong as they claim because it fails to meet the test of sufficient causation. While scientists should always be skeptical and critical of assumptions of all methods employed in wildlife research, more rigorous tests are necessary before we discredit a valuable technique without sufficient empirical evidence.
Article
Numerous studies of behavior and ecology of northern bobwhites (Colinus virginianus) have depended on radiotagging and telemetry for data collection. Excluding the presumably short-term effects of trapping, handling, and attaching radiotransmitters, researchers often assume that little bias is associated with estimating survival and behavioral parameters associated with this technique. However, researchers have not adequately examined these effects on organisms being investigated and have thus assumed demographic information obtained from such methods are valid. In light of this conjecture, it is imperative to evaluate methodological assumptions to ensure research is statistically valid and biologically meaningful. Therefore, we used Burnham's model and program MARK to analyze survival estimates of individually banded and radiotagged bobwhites during an 8-year period (1997–2004) consisting of 6,568 individuals (2,527 radiotagged) via combined analysis of mark—recapture, dead recovery (via harvest), and radiotelemetry data to test the effects of radiotransmitters on bobwhite survival. We also compared band—recapture survival estimates to Kaplan—Meier survival estimates, and we examined the effects of various other factors (e.g., temporal, spatial) on bobwhite survival. Based on Akaike's model selection criterion, the best model including the radiotransmitter covariate (Akaike's Information Criterion adjusted for small sample size bias and overdispersion relative value = 0.72) did not explain more of the variation in survival than models without this effect. Thus, we found the effect of radiotransmitters as negligible. Bobwhite survival varied relative to spatial (e.g., site), temporal (e.g., yr and season), and gender effects. Average annual survival for the 8-year period was 22.76% (1.50 SE) for banded-only and 21.72% (1.49 SE) for radiotagged birds. Survival rate varied annually, ranging from 12.42% (7.51 SE) to 37.16% (8.27 SE), and seasonally, ranging from 23.82% (2.71 SE) to 65.06% (3.23 SE); however, between group (banded-only, radiotagged) survival differences were still inconsequential. We conclude that for our study, radiotelemetry provided reliable survival estimates of an intensively managed bobwhite population, where supplemental food was provided, and this information provided useful data to make practical habitat management decisions. We believe that future radiotelemetry studies would benefit as a whole if researchers conducted similar analyses prior to presenting their results from radiotelemetry data, especially for populations that are more food limited.
Article
Radio-telemetry is often the method of choice for Studies of species whose behaviour is difficult to observe directly. However, considerable debate has ensued about the best way of deriving home-range estimates. In recent years, kernel estimators have become the most widely used method, together with the oldest and simplest method, the minimum convex polygon (MCP). More recently, it has been Suggested that the local convex hull (LCH) might be more appropriate than kernel methods in cases where an animal&apos;s home range includes a priori inaccessible areas. Yet another method, the Brownian bridge (BB), explicitly uses autocorrelated data to determine movement paths and, ultimately, home ranges or migration routes of animals. Whereas several studies have used Simulation techniques to compare these different methods, few have used data from real animals. We used radio-telemetric data from urban badgers Meles meles to compare two sampling protocols (10-minute vs at least 30-minute inter-fix intervals) and four home-range estimators (MCP, fixed kernels (FK), LCH and BB). We used a multi-response permutation procedure and randomisation tests to compare overall patterns of fixes and degree of overlap of home ranges estimated using data from different sampling protocols, and a general linear model to compare the influence of sampling protocols and home-range estimator on the size of habitat patches. The shape of the estimated home ranges was influenced by sampling protocol in some cases. By contrast, the sizes and proportions of different habitats within home ranges were influenced by estimator type but not by sampling protocol. LCH performed consistently better than FK, and is especially appropriate for patchy study areas containing frequent no-go zones. However, we recommend using LCH in combination with other methods to estimate total range size, because LCH tended to produce smaller estimates than any other method. Results relating to BB are preliminary but suggest that this method is unsuitable for species in which range size is small compared to average travel speed.
Article
New demands on our land resources require more stringent controls and management practices. The administration of these controls requires better and more frequent information concerning land use. Although new tools became available to aid in acquiring and processing the data, a major lack in uniform techniques for identifying the land use was a major problem. Creation of a more standard form of classification of land use, based on the capabilities inherent in the various forms of remote sensors and other data sources was a necessary step.A classification has been created, and published in preliminary form, by the Geological Survey of the United States Department of Interior. It is presented as Geological Survey 671, entitled "A Land Use Classification System for Use With Remote Sensor Data". This paper discusses the origin, development, and controlling influences of that classification system.
Article
By studying animal movements, researchers can gain insight into many of the ecological characteristics and processes important for understanding population-level dynamics. We developed a Brownian bridge movement model (BBMM) for estimating the expected movement path of an animal, using discrete location data obtained at relatively short time intervals. The BBMM is based on the properties of a conditional random walk between successive pairs of locations, dependent on the time between locations, the distance between locations, and the Brownian motion variance that is related to the animal's mobility. We describe two critical developments that enable widespread use of the BBMM, including a derivation of the model when location data are measured with error and a maximum likelihood approach for estimating the Brownian motion variance. After the BBMM is fitted to location data, an estimate of the animal's probability of occurrence can be generated for an area during the time of observation. To illustrate potential applications, we provide three examples: estimating animal home ranges, estimating animal migration routes, and evaluating the influence of fine-scale resource selection on animal movement patterns.
Radiolocation telemetry. Pages 95-103
  • R B Brander
  • W W Cochran
Brander, R. B., and W. W. Cochran. 1969. Radiolocation telemetry. Pages 95-103, in R. H. Giles, editor. Wildlife Management Techniques Manual. The Wildlife Society, Washington, D. C., USA.