Colinus Virginianus Research Articles

Effect of Prescribed Fire and Mechanical Treatments on Northern Bobwhite Occupancy in Mesic Pine Flatwoods

We examined whether roller-chopping, mowing, and prescribed fire used to restore groundcover in pine flatwoods habitats affected northern bobwhite (Colinus virginianus; hereafter, bobwhite) occupancy. We surveyed bobwhites using repeated point counts (n = 3), April–June each year, to determine response to prescribed fire and mechanical treatments on Osceola National Forest (Osceola, 78 plots) and St. Sebastian River Preserve State Park (Sebastian, 11 plots) in Florida, USA, 2013–2019. We measured groundcover each year at randomly placed transects within 200-m radius point-count plots. To assess the importance of management covariates, we fit single season occupancy models to predict occupancy (ψ) and detection (p). Detection probability was 0.12 (standard error [SE] = 0.05) and 0.35 (SE = 0.05) on Osceola and Sebastian, respectively. Modeled occupancy on both sites was best predicted by presence of roller-chopping, years since fire, and year. Predicted occupancy was highest on plots with 1 year since fire (Osceola, 0.22 [SE = 0.10]; Sebastian, 0.67 [SE = 0.18]). Predicted occupancy was higher on roller-chopped plots (Osceola, 0.33 [SE = 0.15]; Sebastian, 0.85 [SE = 0.15]) than on mowed (Osceola, 0.08 [SE = 0.03]) or untreated plots (Osceola, 0.07 [SE = 0.03]; Sebastian, 0.38 [SE = 0.34]). Roller-chopping and fire reduced density of palmetto (Seranoa spp.)-shrub vegetation and increased grasses and forbs. To increase bobwhite occupancy and improve habitat suitability of degraded mesic pine flatwoods, we recommend roller-chopping and a 2-year fire frequency.

Effect of Food Distribution on Northern Bobwhite Resource Selection

Supplemental feeding is a common management tactic used to increase survival and reproduction of northern bobwhite (Colinus virginianus; hereafter, bobwhite). Different supplemental feeding methods alter the distribution of resources across a landscape in unique ways and may influence the space use and resource selection of target species differently. Predators may concentrate their movements near fed sites, and different distributions of supplemental feed may encourage bobwhite to concentrate their movements closer to feed than other areas, thereby altering the potential for predator-prey interactions near feed. We used radio-tracked locations and movements in areas with stationary feeders (“feeder fed”) and nonsupplementally fed (“unfed”; study 1, year 1) or nonstationary “broadcast fed” (study 2, year 2) areas to compare resource selection within a Bayesian framework. Second- and third-order resource selection functions indicated bobwhite were more likely to occur in proximity to feeders and feedlines when available, but bobwhite resource selection was more strongly affected by feeders. These results demonstrate that different distributions of food resources can affect prey resource selection, potentially altering the probability of overlap between nontarget predator and target prey species. Managers of bobwhite populations should broadcast feed instead of using feeders to avoid concentrations of bobwhites, which may lead to reduced survival.

Habitat Works: How Partnerships and Habitat Improvement have Restored Quail Populations in the 2C Quail Focus Area

The Missouri Department of Conservation (MDC) began establishing Quail Focus Areas (QFAs) on private lands in 2004. The goal of QFAs was to bring groups of landowners together to manage bobwhite habitat on a larger scale in a targeted landscape. Through a variety of state, federal, and other partnership programs, habitat improvement efforts have resulted in large increases in northern bobwhite (Colinus virginianus; hereafter, bobwhite) numbers in the 2C QFA. In spring 2013, MDC staff and Quail Forever biologists began monitoring bobwhite and songbirds in a portion of the 2C QFA in Carroll County, Missouri, USA and in a control area (without habitat management for bobwhite). This effort is part of the Coordinated Implementation Plan developed by the National Bobwhite Technical Committee as a part of the National Bobwhite Conservation Initiative. The goal of the monitoring plan is to document whether quail habitat management can achieve sustainable bobwhite populations within 5–10 years. We selected a 2,100-ha portion of the 2C QFA where habitat management for quail has been conducted through efforts by landowners, MDC staff, and Quail Forever volunteers. Point-transect surveys were conducted at 48 250-m radius points in spring for bobwhite and songbirds and at 12 500-m radius points in fall for bobwhite coveys. Quail densities ranged from 0.18 quail/ha (95% credible interval [CrI] = 0.09–0.32) to 0.41 quail/ha (95% CrI = 0.30–0.57) in the focus area and from 0.04 quail/ha (95% CrI = 0.01–0.11) to 0.12 quail/ha (95% CrI = 0.06–0.20) in the control area from 2013–2019. We have also documented increases in grassland songbirds through monitoring efforts. Results show that dedicated management efforts were successful in increasing bobwhite density in the focus area.

Adaptive Management and Quail Conservation on Rangelands in the American West

Adaptive management has been and is being practiced with the goal of sustaining populations of wild quails on large areas of rangelands in the American West. Because the current land use practices throughout most of the eastern two-thirds of the United States largely do not promote early-successional vegetation communities, rangelands contain the largest remaining blocks of contiguous (unfragmented) habitat for the northern bobwhite (Colinus virginianus) and the other 5 species of quails found in the western states. Many wildlife professionals on both private and public rangelands are practicing a diverse array of quail habitat and population management actions that could be considered a form of adaptive management—an iterative process used to make decisions in the context of uncertainty. Though this “learning by doing” approach is not always formally labeled adaptive management, these wildlife professionals intuitively recognize the value of the process in sustaining populations of wild quails. We support our assertions about adaptive management with 4 case study examples of adaptive management projects that promote quail conservation—including quail hunting—on both private and public rangelands in the American West. By discussing these scenarios within an adaptive management framework, we hope to highlight current and future opportunities for adaptive management in quail conservation on rangelands and to discuss where adaptive management may be improved or no longer be appropriate.

The Efficacy of Video Cameras to Account for Northern Bobwhites Flushed, but Undetected During Aerial Surveys

Over the past 20 years, conventional distance sampling from a helicopter platform has been used to estimate northern bobwhite (Colinus virginianus; hereafter, bobwhite) density over large areas of rangeland vegetation. However, it has been speculated that aerial surveys can complicate the ability to meet the distance sampling assumption of detecting 100% of the target objects on the transect line due to the restricted observer view from the helicopter. We attempted to use video cameras to determine whether missed detections occurred and whether digital methods could improve the precision of bobwhite density estimates. Our objectives were to 1) determine whether video cameras are a viable option to detect if coveys are flushing behind the helicopter and missed by observers, 2) determine whether coveys are flushing underneath the helicopter and missed by observers, and 3) explore the use of video cameras in a mark-recapture distance sampling (MRDS) framework. We recorded video while traversing line-transects with a helicopter during 4 distance-sampling surveys across 2 ranches in South Texas, USA. For objective 1, we reviewed footage from cameras with a backward-facing view and detected only 1 pair of bobwhites (0.001% of 889 coveys detected) that flushed on video footage recorded during the surveys but were unnoticed by observers. These results indicated that when coveys flushed, they rarely flushed behind the helicopter, and the helicopter flew at what seemed to be the proper speed and altitude to detect late flushes. For objective 2, we reviewed footage from a helicopter-mounted camera that was recorded within a swath underneath the helicopter’s center. We recorded 22 flushes within the swath, none of which was missed by the observers in the helicopter; as a result, we could not complete an MRDS analysis in Program Distance. This study improved confidence in fulfilling the assumptions of distance sampling and resulting density estimates but was limited to flushing birds only.

Northern Bobwhite Demographics and Resource Selection Are Explained by Prescribed Fire with Grazing and Woody Cover in Southwest Missouri

Understanding the effects of landscape management on northern bobwhite (Colinus virginianus; hereafter, bobwhite) population growth requires information about seasonal- and stage-specific demographic parameters linked across the annual cycle. We review results to date from 3 years (2016–2018) of an intensive field study evaluating drivers of bobwhite population dynamics and resource selection during the breeding and non-breeding season in southwest Missouri, USA using data from adult and juvenile bobwhite fitted with radio-transmitters. Land cover of our study sites ranged from large blocks of native grasslands maintained with prescribed fire and grazing to more traditional management resulting in small patches of grasslands interspersed with food plots, disked idle areas, and woody cover. During the breeding season, relative probability of selection by broods increased in relation to proportion of native grass managed by grazing and burning and proportion of cropland. Brood survival was also greatest on native grasslands burned and grazed within the past 2 growing seasons. During the fall and winter, relative probability of selection by adults increased as woody edge density increased. Fall and winter survival increased as distance from trees increased and decreased as distance to shrubs increased. Our integrated population model indicated that the number of young hatched per female and adult breeding season survival were greatest on sites with the most native grassland managed by prescribed fire with grazing. However, non-breeding season survival was greater on sites with more agriculture or food plots and woody cover. Abundance declined across all sites from 2016 to 2019. Our work suggests that native grasslands managed by prescribed fire with grazing can provide quail habitat superior to traditional management that strived for a mixture of agriculture, woody cover, and grassland. The combination of conservation grazing and fire in native grasslands interspersed with shrubs may provide the greatest chance for bobwhite populations to persist in southwest Missouri and similar landscapes.

Spatial and Temporal Analyses of Bobwhite Hunting Dynamics

A variety of factors influence the harvest of northern bobwhites (Colinus virginianus) and where that harvest occurs on a landscape. Many of these factors can be quantified and manipulated to distribute harvest pressure across time and space to meet desired spring densities. We collected spatial hunting metrics using global positioning system units on trucks and hunting dogs, along with detailed hunting logs from 211 quail hunts during the 2018–2019, 2019–2020, and 2020–2021 statewide hunting seasons in Jim Hogg County, Texas, USA. We found that hunting parties effectively covered 23.8 ± 0.3 hectares per hour, with hunts lasting 3.5 ± 0.1 hours in the morning and 1.7 ± 0.1 hours in the evening. Hunts were less productive during the early season (November–mid-December), with 13% fewer encounters per hour and 31% lower harvest per encounter. We expected daily harvest to increase with hunt velocities, but found no significant relationship with the velocity of either pointing dogs or vehicles. However, as we predicted, total hunting pressure (hunts per 50-meter × 50-meter area) decreased by 12% (range = 7–17) for every 5% increase in brush density and every 10-meter increase in the distance to the nearest access road. Our findings can assist landowners and managers in the distribution of harvest and hunting pressure across properties and hunting seasons.

Exploring a Plant-Diversity Hypothesis to Explain Helminth Prevalence in Northern Bobwhite in Texas

Helminths, in particular eyeworms (Oxyspirura petrowi), may be a factor influencing northern bobwhite (Colinus virginianus; hereafter, bobwhite) populations in Texas, USA. Mean eyeworm prevalence in Texas appears to be greater in the Rolling Plains (55.1%) than the Rio Grande Plains (16.4%), a pattern generally attributed to possible differences in the occurrence of insects, the intermediate hosts of eyeworms. We explored an alternative hypothesis centered on plant diversity. Many plants possess phytochemicals with anthelmintic properties. Because wild animals suffering from parasitic infestations are capable of self-medicating via diet selection, organisms foraging in diverse communities may be expected to possess lower parasite levels. We predicted that plant diversity would be greater and bobwhite diet more diverse in the Rio Grande Plains than the Rolling Plains, which in turn would potentially expose bobwhites to more plants with anthelmintic properties and therefore result in lower parasite prevalence. We conducted a literature review of plant diversity, anthelmintic plants, and bobwhite diet in Texas to explore this hypothesis. Our results indicated that 1) plant diversity was higher (24–96%), 2) the number of anthelmintic plants greater (33%), and 3) bobwhite diet more diverse (120%) in the Rio Grande Plains compared to the Rolling Plains. We documented a mean (± standard error) eyeworm prevalence of 16.4 ± 7.27% in the Rio Grande Plains (n = 4 sites) and 55.05 ± 2.93% in the Rolling Plains (n = 20 sites). The mean cecal-worm prevalence was documented at 74.8 ± 18.21% in the Rio Grande Plains (n = 5 sites) and 79.79 ± 2.12% in the Rolling Plains (n = 19 sites). Regarding plant diversity, the Rio Grande Plains contained more potential anthelmintic plants (n = 96 species) than the Rolling Plains (n = 72 species). In cross-referencing these plants with the bobwhite diet, we found that 23 plants with possible anthelmintic properties had been documented in the bobwhite diet in the Rio Grande Plains, whereas only 17 such plants were documented in the bobwhite diet in the Rolling Plains. Our study provides circumstantial evidence for the plant-diversity hypothesis and warrants experimental testing.

Nest Hatch Chronology of Northern Bobwhite and Implications for Management

Managers in Missouri, USA, and in other Midwestern states have long operated under the belief that the peak of nest hatching for northern bobwhite (Colinus virginianus; hereafter, bobwhite) is 15 June. Though it is widely understood that bobwhite nests hatch throughout the summer, many management decisions are made based on the accepted peak. Fully understanding the dynamics behind bobwhite nest timing is critical, as management activities in nesting cover during summer are common. To better understand nest chronology, we used radio-telemetry to monitor nest incubation initiation, hatch date, and renesting rate on 6 conservation areas in southwestern Missouri from 2014 to 2018. Nest hatch date varied by area and year, but only 8.5% of nests hatched on or before 15 June. The 7-day interval during which the most nests hatched was 15–21 June, but we also saw high numbers of nests hatch in early July and mid- to late August. The median hatch date across all 5 years of the study was 17 July. Our results suggest that the entire summer is critical for bobwhite nesting activities, with late summer being just as important as the early summer months. We encourage bobwhite managers and conservation program policymakers across the Midwest to rethink previously held constructs of bobwhite nest timing. We also recommend that summer disturbances to nesting cover be kept to a minimum when the goal is to maximize bobwhite reproductive output.

Exploring the Relationships between South Texas Northern Bobwhite Populations and Cecal Worms via System Dynamics

Community ecology historically focused on plants and free-living organisms; however, problems such as defining habitat boundaries and obtaining adequate sample sizes arise when evaluating such communities. The unique nature of host-helminth systems allows parasite community ecologists to avoid these problems when testing ecological hypotheses. Unlike free-living communities that have artificially constructed boundaries, parasite communities have well-defined unambiguous boundaries within host individuals. Due to the inherently complex and dynamic nature of ecological systems, traditional experimental methods often require expensive, long-term trials beyond investigators’ time and resource budgets. Conversely, a system dynamics approach facilitates learning about such systems via simulation of ecosystem processes integrated with historical data (both quantitative and qualitative). Relatively few studies focus on parasites in South Texas, USA, although research on avian host-parasite systems has shown that parasites can potentially regulate host populations. The northern bobwhite (Colinus virginianus; hereafter, bobwhite) is a game species of ecological, economic, cultural, and recreational importance in Texas that has been experiencing a long-term, widespread decline. To holistically examine the bobwhite-helminth system in South Texas, we created a system dynamics model capturing the feedback relationships between a South Texas bobwhite population, a grasshopper (family Acrididae) population, and the corresponding cecal worm (Aulonocephalus pennula) populations on a hypothetical 1,000-acre ranch in South Texas. The model structure, constructed in Vensim® PLE 7.2 software (Ventana Systems, Inc.), integrates the hypothesized biotic and abiotic drivers (precipitation, parasite load, insect abundance, and quail density) unique to the host-helminth system over 7 years (2012–2019). Our specific objectives were to 1) develop a working baseline model to replicate the synergistic population dynamics among bobwhite, grasshopper, and cecal worm populations and then 2) test hypotheses about each population’s boom-and-bust cycles resulting from environmental stressors (e.g., drought). Applications of the model can provide landowners and natural resource managers with a better understanding of the complex dynamics occurring among bobwhite, grasshopper, and cecal worm populations in South Texas.

Evaluating the Harvest Rate Recommendation for Northern Bobwhites in South Texas

The current harvest rate recommendation for northern bobwhites (Colinus virginianus; hereafter, bobwhite) in South Texas, USA is 20% of the autumn population, including crippling loss. This recommendation is based on population simulations of empirical data. We completed the first field evaluation of the 20% harvest recommendation by comparing prehunting and posthunting bobwhite density estimates on a hunted and nonhunted site in South Texas during the 2018–2019, 2019–2020, and 2020–2021 statewide bobwhite hunting seasons in Jim Hogg County, Texas. We conducted line-transect distance sampling surveys on 4 occasions per year (early November, mid-December, late January, early March) from a helicopter platform and prescribed the 20% annual bobwhite harvest from the November density estimate. According to our bobwhite density estimates, we found that bobwhite mortality (e.g., population decline) varied seasonally between hunted ( = 54% ± 3%) and nonhunted sites ( = 46% ± 5%). Our spring density estimates on both sites (i.e., hunted vs. nonhunted) were similar through the first 2 years but diverged in 2020–2021, with bobwhite densities that were 129% higher on the nonhunted site. Comparing our annual spring density results to the means reported from population models (i.e., 100-year simulations) used to create the 20% harvest recommendation, we found that the mean spring density of the model simulations was higher than our mean field estimates on both our hunted (+59%) and nonhunted sites (+77%). We recommend a conservative approach to prescribing a bobwhite harvest in South Texas, such as using the lower 95% confidence interval of a bobwhite abundance estimate for calculating harvest prescriptions, due to variability within density estimates and bobwhite survival in semiarid ranges.

Relationships between Meteorological and other Variables and Bobwhite Spring Call Counts

Accurate assessment of quail population trends is critical to the success of future conservation efforts. Financial considerations and time constraints often limit population trend estimates to indices, the most common of which are spring call counts and autumn covey counts. While all indices have limitations and caveats, spring call count data specifically possess variability that makes them ill-suited for detecting fine-scale trends. However, because spring call counts record calling males and are relatively easy to conduct, they are assumed to represent an index of breeding potential and produce the most data per unit cost. Here, we examine their variability, comparing the number of male northern bobwhites (Colinus virginianus; hereafter, bobwhite) calling and weather measurements recorded during >4,000 spring call counts conducted May–July 2014–2017. The number of male bobwhites recorded per call count decreased >2 hours after sunrise, as ambient temperatures increased, but increased with relative humidity. An increase in ambient noise was associated with recording fewer male bobwhites. There was no correlation with either wind speed/hour for 3 of 4 years, or with the Palmer Drought Severity Index. Comparing these results with other spring call counts in the literature highlights inconsistency in spring call count timing, and discrepancies between call count protocols and weather conditions that affect detection probability. We suggest incorporating these results into future call counts to more accurately assess bobwhite population trends.

Detection Rates of Northern Bobwhite Coveys Using a Small Unmanned Aerial System-Mounted Thermal Camera

The northern bobwhite (Colinus virginianus; hereafter, bobwhite) requires intensive monitoring to evaluate management efforts and determine harvest rates. However, traditional monitoring techniques (e.g., covey-call surveys) are labor-intensive and imprecise. Small unmanned aerial systems (sUASs) 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 (3, 6, and 12) and cover type (grass, shrub, and forest) on covey detectability by a sUAS equipped with a thermal camera. We hypothesized that forest would have the lowest covey detection due to trees obstructing detection of the thermal signature and that larger covey size would improve covey detection due to the formation of larger, more visibly distinct thermal signatures. We placed groups of known-size, pen-reared bobwhites in steel mesh cages (3, 6, and 12 individuals/cage) in 3 vegetation types (grass, shrub, and forest) among predetermined locations on a private farm in Clay County, Mississippi, USA (3 replicates, 27 total cages). At civil twilight on 5 March 2020, the sUAS flew a systematic route over the cage area at 30 m above ground level, capturing thermal infrared photographs every 5 seconds. To assess detection, we distributed 57 photographs to 31 volunteers and asked them to assign a binary value for detection (1, 0) regarding covey presence in each photograph. Overall true positive rate was 0.551 but improved with increasing covey size. By vegetation type, simulated coveys in grass had the lowest true positive rate by photograph (0.403), followed by forest (0.562) and shrub (0.605). Results indicate that sUASs and thermal camera technology could be a viable method for surveying intact bobwhite coveys, especially if detection of smaller groups and those in denser vegetation improves. As this technology advances, we recommend that 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.

Home Range and Space Use of Northern Bobwhite Under Two Different Management Models in Southwestern Missouri

Northern bobwhite (Colinus virginianus; hereafter, bobwhite) management in Missouri, USA has traditionally been focused on providing an interspersion of grass, crop, old field, and woody cover juxtaposed to disked idle areas and food plots to maintain bobwhite populations. This traditional model is implemented with the goal of providing all essential habitat components within 40-acre blocks throughout a larger area used by a population. While this model can produce usable bobwhite space in agriculture-dominated landscapes, it may not be the most effective or efficient approach to producing and maintaining bobwhite in grassland-dominated landscapes. In southwestern Missouri native tallgrass prairie conservation areas are managed primarily with historical ecological processes, such as fire and grazing, to produce the desired patchy habitat mosaic. Additionally, it has been on these native tallgrass prairie conservation areas that managers have seen the most stable and productive bobwhite populations. Over a 5-year period (2014–2018) we quantified movements of northern bobwhite on 3 traditionally managed areas (n = 185) and on 3 managed native tallgrass prairie conservation areas (n = 211) to determine whether home range sizes and space use differed between these two management models. We used the 6-month (Apr–Sep) breeding period to determine core area, home range, mean movement rate, and maximum distance moved. Overall (pooled) home ranges of bobwhite did not differ significantly between traditional and grassland managed areas; however, there were significant yearly differences between management models and study areas. Males generally had larger home range sizes and had higher movement rates than females. For the 5 years of the study few birds made long-distance movements (>1.6 km; 3%), and all remained relatively close to capture locations in winter (Feb–Mar). For both traditional and grassland managed areas, bobwhite selected for areas that had disturbance (fire and grazing) in the last 2 years and for the native grassland vegetation type. These findings suggest that areas managed under the grassland management model provide preferred habitat for bobwhite and could result in significant improvement in habitat quality for tallgrass prairie wildlife.

Landowner Cooperative Key to Success in the Bee Ridge Quail Focus Area

The Missouri Department of Conservation (MDC) began establishing Quail Focus Areas (QFAs) on private lands in 2004. The goal of QFAs is to increase and expand quail habitat management efforts around a core area. Because most (93%) of the landscape of Missouri, USA is in private ownership, habitat improvement programs on private lands have greater potential to impact quail populations than on public lands alone. A motivated group of landowners led the charge to begin habitat improvement efforts in the Bee Ridge QFA. This group was instrumental in starting earlier monitoring efforts to determine whether habitat improvements were leading to increased northern bobwhite (Colinus virginianus; hereafter, bobwhite) numbers. In fall 2017, MDC staff began monitoring bobwhite and songbirds in a portion of the Bee Ridge QFA in Knox County, Missouri and in a control area (without habitat management for bobwhite). This effort is part of the Coordinated Implementation Plan developed by the National Bobwhite Technical Committee as a part of the National Bobwhite Conservation Initiative. The goal of the monitoring plan is to document whether quail habitat management can achieve sustainable bobwhite populations within 5–10 years. We selected a 2,225-ha portion of the Bee Ridge QFA where habitat management for quail has been conducted through efforts by landowners and MDC staff. Point transect surveys are conducted at 46 250-m radius points in spring for bobwhite and songbirds and at 12 500-m radius points in fall for bobwhite coveys. Bobwhite densities ranged from 0.23 bobwhite/ha (95% credible interval [CrI] = 0.14–0.35) to 0.27 bobwhite/ha (95% CrI = 0.15–0.43) in the focus area and 0.03 bobwhite/ha (95% CrI = 0.01–0.08) to 0.06 bobwhite/ha (95% CrI = 0.01–0.15) in the control area from 2013 through 2019. Landowners working together to implement recommended habitat management practices resulted in greater quail and songbird numbers in the focus area, compared to the control area.

Measuring Multiple Demographic Rates in Two Populations of Northern Bobwhite

Demographic rates of northern bobwhite (Colinus virginianus; hereafter, bobwhite) may vary spatially and temporally, and understanding the significance of these individual rates to population performance is critically important to bobwhite management. We present descriptive evidence from 2 populations that were simultaneously monitored from 2015–2020 that suggests different demographic rates can be more important to population performance than other demographic rates within the same region. Our objective was to understand the relative importance of various demographic rates to population performance in separate and seemingly stable populations. We monitored bobwhite seasonal survival and reproductive demographics on 2,475 bobwhites via radio-telemetry and estimated fall density using fall covey counts. Both sites maintained high densities (i.e., ≥3.45 birds/hectare) and remained relatively stable throughout the study period. On one site in the Red Hills region near Monticello, Florida, USA, bobwhite experienced comparatively low seasonal survival, but higher reproduction, including more frequent multiple-brood production. One hundred and twenty-nine kilometers away on a study site near Albany, Georgia, USA, bobwhite demonstrated consistently higher survival and lower reproductive output, including less multiple-brooding compared to the Red Hills population. This suggests, at a minimum, that compensatory or density-dependent reproduction may be occurring in these populations and regional population dynamics can vary locally even among stable populations.

Cascading Effects of Hunting Disturbance on Northern Bobwhite Behavior, Physiology, and Survival

The northern bobwhite (Colinus virginianus; hereafter, bobwhite) is an important gamebird across the United States and has been in decline for several decades. As a commonly hunted prey species, the bobwhite provides an ideal study species to investigate the use of proactive and reactive antipredator behaviors in response to hunting pressure. We designed an experiment to understand how late-season hunting affects bobwhite demographics using fecal glucocorticoid (fGCM) concentrations, foraging and movement behaviors, survival, and breeding season metrics. Our results show that bobwhite responded to increased interactions with a shotgun through proactive responses. After one encounter with a discharged shotgun, bobwhite began foraging farther from supplemental feed where the risk of encountering a hunting party was the greatest (β = 0.21, 95% Bayesian credible interval [CrI]: 0.06–0.36). Bobwhite responded to increased hunting pressure, particularly late-season hunting pressure, via reactive responses through increased fecal glucocorticoid metabolite (fGCM) concentrations (β = 2.18, 95% CrI: 0.21–4.15), resulting in decreased survivorship in non-harvested individuals (β = -0.42, 95% CrI: -0.77 to -0.07) and decreased fecundity (β = -0.17, 95% CI: -0.31–0.09). These results can help inform hunting season regulations and management decisions aiding in bobwhite recovery.

Highly Variable Autumn Calling Rates of Northern Bobwhite Following Translocation

Fall covey counts are a popular index for monitoring population trends of northern bobwhite (Colinus virginianus; hereafter, bobwhite), but their utility is tenuous under different scenarios. Detecting an individual covey is the product of the probability that the covey’s activity center is located within the sampling frame, the probability the covey is located within the sampling frame during the sampling periods, the probability of the covey vocalizing, and the probability an observer will detect a calling covey. Researchers attempt to maximize detection or account for these potential sources of error using standardized protocol of limiting counts to certain weather conditions, replication, and distance sampling. Variation in calling rates across a range of bobwhite densities could lead to tenuous inference of population abundance from fall covey counts, particularly at low densities. Our objectives were to assess fall calling rates at 2 sites with low bobwhite density during population restoration. Our study sites were located in Erath County, Texas, USA and Leon County, Florida, USA and received translocated bobwhite during 2019 and 2020. We hypothesized calling rates would be influenced by the number of adjacent coveys that called, and thus, would be low for our sites. Although we did not estimate bobwhite density on our study sites, we surmised that their respective populations were /3 ha. Calling rate at the Erath County site was 0 in 2019 (n = 10 counts) and increased to 0.79 (standard error [SE] = 0.07, n = 34 counts) in 2020. Calling rate was assessed only in 2020 at the Leon County site and averaged 0.13 (SE = 0.07, n = 23 counts). Detection rate at count stations was 0 in 2019 and 0.78 (SE = 0.08, n = 27 calling coveys) in 2020 at the Erath County site. In 2020, detection rate at count stations was 0 (n = 3 calling coveys) at the Leon County site. We documented high annual variation in calling rates among low-abundance sites, suggesting researchers should seek to empirically estimate this parameter rather than applying arbitrary correction factors based on previous literature. Low and variable calling rates limit detection and can bias inference.

Lessons Learned from the First 10 Years of the Oaks and Prairies Joint Venture’s Grassland Restoration Incentive Program (GRIP)

The Oaks and Prairies Joint Venture (OPJV) was formed in 2008 as a public-private partnership of agencies and organizations working across jurisdictional boundaries in portions of Texas and Oklahoma, USA. The OPJV’s major focus is reversing declines of bird populations by supporting strategic habitat conservation (biological planning, conservation design, conservation delivery, mission-based monitoring, and assumption-driven research) for northern bobwhite (Colinus virginianus), grasslandobligate species, and their respective habitats. Our objective for this paper is to document and share a decade of lessons learned in developing a partnership-based native grassland conservation program to meet grassland bird conservation targets. We share lessons learned about how to manage partnership-based, large-scale habitat incentive programs to better target project locations and habitat practice types. To establish initial shared purpose, OPJV partners drew from population and habitat objectives in various state, national, and international bird conservation plans, stepped down to ecoregion levels, to establish the OPJV Grassland Bird Conservation Business Plan. The plan has 4 strategies directly contributing to the achievement of OPJV grassland bird biological objectives that are directly supported by OPJV staff or resources (or both). The overall objective for 2015–2025 was 619,978 ha (1,532,000 acres) improved within 40 focal counties, representing 1/3 of all counties in the OPJV. Our main strategy was to provide financial incentives through the OPJV Grassland Restoration Incentive Program (GRIP) to private landowners for conducting beneficial grassland bird habitat management practices. Since inception in 2013, GRIP has treated over 44,515 ha (110,000 acres) on private lands in Texas and Oklahoma, with the goal of maintaining highquality grassland bird habitat on treated hectares for ≥5 years. In 2017, OPJV partners working with USDA Natural Resources Conservation Service, began a 5-year, $6.1 million partnership to provide additional technical and financial assistance to private landowners interested in grassland conservation through the Regional Conservation Partnership Program (RCPP). A project scoring system was designed to strategically encourage individual projects to include prescribed fire—one of the lowest cost practices per hectare—as a recurring practice to maintain program-achieved grassland improvements. Post-inception of the RCPP, the area treated with prescribed fire increased from approximately 809 ha (2,000 acres)/year to 3,237 ha (8,000 acres)/ year, while maintaining average annual hectares of all other beneficial practices. Beginning in 2013, bird point count surveys were conducted annually to monitor northern bobwhite and grassland bird populations, including a subset of points under the National Bobwhite Conservation Initiative (NBCI) Coordinated Implementation Plan. To

Efficacy of a Preemergence Herbicide Following Postemergence Control to Reduce Sericea Lespedeza in Old Fields Managed for Northern Bobwhite

Sericea lespedeza (Lespedeza cuneata; hereafter, sericea) is a nonnative forb that commonly invades sites managed for northern bobwhite (Colinus virginianus; hereafter, bobwhite). Sericea can reduce habitat quality for bobwhite as it outcompetes native plants that provide forage and cover. Bobwhite eat sericea seed, but seed are relatively indigestible and may limit nutrition intake and reduce the fecundity rate. Postemergence herbicides, including glyphosate, triclopyr, and fluroxypyr+triclopyr, control standing sericea, but do not provide preemergence control, which would increase long-term control because sericea annually produces large amounts of hard seed with high dormancy rates. Imazapic is labeled to provide preemergence control, but no study has evaluated preemergence applications of imazapic following postemergence herbicides to control sericea and promote native plants important for bobwhite. Additionally, data evaluating various rates of imazapic to control sericea are lacking. We currently are evaluating the efficacy of glyphosate and fluroxypyr+triclopyr, applied alone post-emergence and in conjunction with 3 preemergence rates of imazapic, to reduce coverage of sericea at 4 sites in Tennessee and Alabama, USA. We split each site into 8 treatment units and control and assigned the following treatments: glyphosate, fluroxypyr+triclopyr, glyphosate with 48, 96, and 144 ml/ha (4, 8, and 12 oz/acre) imazapic, and fluroxypyr+triclopyr with 48, 96, and 144 ml/ha imazapic. We applied 767 ml/ha (2 qt/acre) glyphosate and 192 ml/ha (16 oz/acre) fluroxypyr+triclopyr in August 2018 to control established sericea. We measured coverage of native forbs, native grasses, and sericea during the 2019 and 2020 growing seasons to determine the efficacy of treatments on sericea and the native plant community. Both glyphosate and fluroxypyr+triclopyr reduced sericea coverage 1 and 2 growing seasons following treatment, but we documented no difference in reduction of sericea coverage between postemergence treatments. We will apply imazapic in March 2021 at 3 different rates to determine whether a preemergence application improves sericea control. Our results on the effectiveness of a preemergence application after postemergence applications should provide valuable information to managers trying to control sericea on lands managed for bobwhite.