Bobwhite Quail Ecology & Management

Contributed Oral Presentations

Contributed paper sessions will be available on-demand for the duration of the conference, then again at the conclusion of the conference.


Meso-Predator Abundance in Relation to Bobwhite Mortality Density and Nest Sites
Brandon Consalus; Heather Mathewson; John Palarski
Northern bobwhite (Colinus virginianus; hereafter bobwhite) is an upland nesting galliform most commonly found in the southern regions of the United States. Recent estimates suggest that bobwhite populations are declining at 4% per annum. A large contributor to bobwhite mortality is predation. In Texas, meso-predators such as raccoon (Procyon lotor), virginia oppossum (Didelphis virginiana), nine banded armadillo (Dasypus novemcinctus), bobcat (Lynx rufus), gray fox (Urocyon cinereoargenteus), and coyote (Canis latrans), are the most prevalent nest predators of bobwhites, while raccoon (Procyon lotor), bobcat (Lynx rufus), gray fox (Urocyon cinereoargenteus), and coyote (Canis latrans) are the most prevalent adult predators. Our objectives are to 1) asses meso-predator abundance on a 1011 ha site in the Cross Timbers ecoregion of Texas where 167 bobwhites were recently reintroduced, and 2) evaluate change in meso-predator land use throughout the bobwhite breeding season. We used camera traps spaced evenly across the study area to detect whether meso-predators changed their movement patterns to favor areas of increased bobwhite presence and nest locations. As the bobwhite breeding season progressed throughout 2019 and 2020, we recorded the number of meso-predator sightings at each camera location, GPS coordinates of bobwhite mortalities, and GPS coordinates of both successful and unsuccessful nest sites. Using Arc Map 10.6.1 we created a kernel density map of bobwhite mortalities and a map illustrating successful and unsuccessful nest attempts. In each map, we included points that illustrated predator abundance at each camera location. Findings from this study will illuminate how meso-predator abundance changes in response to an influx of wild bobwhite.
Detection Probability of Northern Bobwhite Coveys Using a Small Unmanned Aerial System-Mounted Thermal Camera
Megan E. Martin; Raymond Iglay; Kristine O. Evans; Lori A. Hearon; Jesse I. Morrison; Mark D. McConnell
Northern bobwhites (Colinus virginianus) require intensive monitoring to evaluate management efforts and determine harvest rates. However, traditional monitoring techniques (i.e., covey-call surveys) are labor-intensive and imprecise. Small unmanned aerial systems (sUAS) mounted with thermal cameras have demonstrated promise for monitoring multiple avian species and could provide a less intensive and more effective approach to monitoring bobwhite coveys, assuming coveys produce a recognizable heat signature. To assess sUAS monitoring, we evaluated the influence of bobwhite covey size and vegetation type on detectability of coveys by a sUAS mounted with a thermal camera. We placed steel mesh cages with variable group sizes (3, 6, 12 individuals) of pen-raised bobwhite in three vegetation types (grass, shrub, forest) among pre-determined locations on a private farm in Clay County, Mississippi. We equally replicated group sizes and vegetation types and created a flight path based on a 30-meter radius around each pre-determined bird location (3 replicates, 27 locations total). Beginning at civil twilight, we flew a sUAS-mounted thermal camera along the flight path at 30 m altitude, taking pictures approximately every 5 s. To assess detection, we distributed photos to 20 volunteers and asked them to assign a binary value for detection (1, 0) regarding covey presence. We measured vegetation at each bird location and used logistic regression to evaluate differences in detectability. Results indicate that detectability was extremely low (<20%) and not influenced by vegetation type. However, detectability was greatest in 12-bird coveys. Our results indicate that our combination of sUAS and thermal camera technology is not a viable surveying method for bobwhite coveys. However, as this technology improves, we recommend future research focus on evaluating the efficacy of this novel methodology through assessing the influence of weather conditions, camera specifications, flight speed, and altitude, as well as assessing machine learning for processing photos.
Evaluating Density-Dependent and Density-Independent Influences on Northern Bobwhite Population Growth Rates
Mark D. McConnell; William E. Palmer; Shane D. Wellendorf; L. Wes Burger, Jr.; James A. Martin
Understanding population processes over long periods of time is a common objective in applied wildlife science. Northern bobwhite (Colinus virginianus; hereafter, bobwhite) populations have been studied for nearly a century, yet uncertainly remains regarding factors that contribute to population regulation. Specifically, the relative influence of density-dependent and density-independent factors on population growth rates is unknown. We used a 42-year capture recapture dataset from Tall Timbers Research Station (TTRS) to investigate the contribution of density-dependent and density-independent factors on population growth (r) of a stable bobwhite population. We used a closed-recapture, Bayesian state-space model to estimate abundance and quantified multiple density-independent covariates associated with local and regional weather variables and habitat quality. We created an a priori list of candidate variables that represent hypotheses of density-dependent and density-independent processes that may affect population growth. We used Gibbs variable selection to estimate the posterior weights for each hypothesis. We observed that the TTRS bobwhite population is regulated by the combined influence of density-dependent and density-independent factors. Specifically, we found strong support for linear density-dependence, weather during the non-breeding season (Oct. 16 – Apr. 14), and habitat quality during the breeding season. Our study provides support for the concomitant influence of density-dependent and density-independent processes on bobwhite population regulation. The presence of density dependence portends compensatory mortality in response to harvest but more research is needed to establish the strength of density dependence across varying geographies. We encourage researchers and mangers to incorporating density-dependent and density-independent effects into predictive models.
Translocation of Northern Bobwhite in Central Texas
John D. Palarski; Heather Mathewson; Brad Kubecka; T. Wayne Schwertner; Dale Rollins
Translocation of northern bobwhite (Colinus virginianus) is a conservation tool to reintroduce and re-stock existing populations across their range. Despite numerous translocation efforts, the effects of source population, particularly subspecies, on demographic parameters in bobwhite is not well understood. Texas has three primary subspecies of wild bobwhite—C. v. taylori (west Texas) and C. v. texanus (south Texas) are the most common. Our objectives were to monitor survival, dispersal, and reproduction of these two translocated subspecies. We translocated 167 (n = 64 C. v. talyori; n = 103 C. v. texanus) and 237 bobwhites (n = 46 C. v. talyori; n = 191 C. v. texanus) to a 1,100-ha site in north central Texas during March 2019 and 2020, respectively. We employed a soft release strategy whereas we sequestered individuals for 1-4 weeks prior to release. We radiomarked 111 (n = 56 C. v. taylori; n = 55 C. v. texanus) and 110 bobwhites (n = 46 C. v. taylori; n = 64 C. v. texanus) during 2019 and 2020, respectively. Cumulative survival for 1 April – 1 Sept 2019 was similar for C. v. texanus (S= 0.046) and C. v. taylori (S= 0.049) individuals. We observed 17 individuals disperse off site (minimum known dispersal = 1.6 km) and we located 9 nests (n = 5 west Texas, n = 4 south Texas) during 2019. Most mortality events (58%) during 2019 occurred in the first 30 days post-release. We will continue to monitor radio-marked individuals during the 2020 breeding season. Findings from this study will inform managers who wish to translocate bobwhite on the effects of source population.
Predation Management and Spatial Structure Moderate Extinction Risk and Harvest of Northern Bobwhite
John M. Yeiser; Alexander L. Jackson; D. Clay Sisson; Theron M. Terhune; James A. Martin
Density dependence, immigration, and emigration can considerably influence wildlife population demographics. Population models used to evaluate common actions like predator management and harvest in the absence of these processes may lead to poor management decisions. Here, we use a harvest system for a common game bird to demonstrate that the incorporation of spatial structure and the associated ingress and egress of individuals improve our understanding of the system and reduce the uncertainty about the efficacy of predator management across a wide range of environmental conditions. Also, we incorporated density dependence as a regulatory process for these populations. Our theoretical models parameterized with empirical vital rates indicated that immigration and emigration are important to the stability of the system. Weak linear density dependence emerged as a likely regulatory process in our system which lead to the partial compensation for harvest. Moreover, in accordance with empirical studies, predator management improved harvest opportunities and reduced the probability of local extinctions. Practitioners often ignore the contribution of immigration and emigration to local demographics; however, recent literature reviews and our study indicate that these processes are critical to our understanding of animal ecology and management. In the interest of the conservation of species that are both hunted and at risk of extirpation in some geographies, predator management may not only increase hunter success, but it may be a tool to reduce the probability of extirpation.
Histopathology of Quails in Trans-Pecos, Texas
Trey E. Johnson; Ryan O’Shaughnessy; Dale Rollins; Josh G. Cross; Ryan S. Luna
Quail populations in Texas have declined over the past few decades due primarily to habitat loss. A myriad of other factors have been investigated as well. However, the role that parasites may play in this decline has been a recent topic of concern. To help address this, we collected scaled (Callipepla squamata), Gambel’s (Callipepla gambellii), and Mearn’s quail (Cyrtonyx montezumae) from across the Trans-Pecos ecoregion of Texas via hunter-harvest under Texas Parks and Wildlife Department (TPWD) scientific permit number SPR-1118-296. Quail samples were then necropsied to determine the occurrence of eyeworms (Oxyspirura petrowi) and cecal worms (Aulonocephalus pennula). Individual quail organs were submitted to the Texas A&M University Veterinary Medicine Diagnostic Lab (TVMDL) where histopathological analyses were conducted to gain information on parasite-related tissue damage and to document other pathogenic factors. From this, we identified several parasites that had never before been documented in the quails of the Trans-Pecos ecoregion of Texas.
Use of Cover Crops by Ring-Necked Pheasant and Northern Bobwhite in the Corn Belt
Taylor R. Shirley; Adam K. Janke
In agriculturally dominated landscapes, nesting habitat for gallinaceous birds, such as the ring-necked pheasant (Phasianus colchicus) and northern bobwhite (Colinus virginianus), can be a limiting factor in successful reproduction. Historically, small grain fields, pastures, and hay comprised a significant area in the Corn Belt and provided nesting habitat for upland birds. However, with intensification of production systems, small grain plantings and pastures have decreased, contributing to the decline of many grassland birds. Some small grains are being reintroduced to agricultural systems through use of fall-seeded cover crops that seek to improve water quality and soil health and may provide additional benefits to wildlife. The objectives of our study were to determine the use of fall-seeded cover crops by breeding pheasants and bobwhites in the Corn belt, and to evaluate the potential suitability of fall-seeded cover crops as nesting habitat for these species. We used radio telemetry and nest searching to document pheasant and bobwhite use of cover crop fields and adjacent grasslands to understand nesting chronology and nest site selection. We used vegetation surveys to quantify the vegetation composition at nest sites and at random points within each field. We used stationary time-lapse cameras to quantify changes in growth and density of vegetation relative to nesting chronology and brood-rearing. Preliminary findings for radio telemetry and nest searching efforts during 2019 include: 23 nests in CRP, 1 nest in a grassy fence-row, and 1 nest in cover crop. Further analysis is currently in progress to address our objectives, and field data collection efforts will be completed during spring-summer of 2020 and will be the focus of our presentation.
Applying Spatial Capture-Recapture to Estimate Effect of Landscape Structure on Northern Bobwhite Density
Paige Howell; Nathan Wilhite; Rachel Gardner; Jessica Mohlman; Richard Chandler; Ira Parnell; James Martin
Northern bobwhite (Colinus virginianus) are an ecologically and economically valuable species in the United States. Managers invested in maintaining viable populations need accurate estimates of local densities in order to evaluate the efficacy of different management strategies. Here, we present the first application of spatial capture-recapture (SCR) to estimate population density for northern bobwhite, a gallinaceous upland gamebird species. We deployed a fixed array of 395, 262, and 268 funnel traps in 2016, 2017 and 2018, respectively, on the Di-Lane Wildlife Management Area in Waynesboro, Georgia. Our top model for each year included the effect of age and proportion of hardwoods on density, with the highest density of juveniles (0.32 birds/ha, 95% CI = 0.28, 0.37) and adults (0. 10 birds/ha, 95% CI = 0.08, 0.12) estimated in 2016. This result is congruent with the life history of bobwhite (i.e., early reproductive maturity, high productivity and low probability of survival to adulthood) and the timing of our trapping (i.e., in the autumn after the breeding season). The age ratio from these density estimates could potentially be used as a spatially-explicit estimate of productivity without the need to collect nesting and brood success data using telemetry. Our results also indicated that bobwhites avoided hardwood forests; thus, lowering density in those areas. Previous research supports our findings that closed canopy forests negatively affect bobwhite demography. SCR may require additional logistical and financial resources relative to other data collection methods. However, SCR makes modelling spatial variation in density straightforward, and can be used to gather data to simultaneously understand population structure, vital rates, and movement.


Contributed Oral Presentations
Location: Virtual Date: Time: -