Bobwhite Abundance Research Articles

Northern bobwhite (Colinus virginianus) population response to anthelminthic treatment in the Rolling Plains ecoregion of Texas, 2014–2016

Northern bobwhite quail (Colinus virginianus) are an economically significant gamebird that has experienced continued general decline in the Rolling Plains ecoregion of Texas. Habitat loss and changing environmental conditions have been cited as major contributors to this decline, with factors such as parasites being considered inconsequential. To better assess the impacts of parasite infections on bobwhite populations in the Rolling Plains, bobwhite abundance was monitored in response to anthelminthic treatment. With the prevalence of Oxyspirura petrowi and Aulonocephalus pennula infections in quail from Mitchell County, Texas confirmed by previous studies, the anthelminthic agent Fenbendazole was introduced as a means of parasite control in 2014–2015. Bobwhite abundance was determined through a series of call counts which provided an index of bobwhite populations and were conducted throughout the course of the study. In 2016, call counts revealed a significant increase of bobwhite in the area subject to Fenbendazole treatment, while untreated areas showed no changes in abundance. Fall populations of bobwhite in the treated zone approached 300% of those in untreated areas, these findings suggest that parasites may have a more significant impact on quail populations in the Rolling Plains than previously suspected. With the importance of bobwhite as a game bird in the Rolling Plains, the potential impacts of parasites must be taken into consideration as a factor contributing to bobwhite declines. Further research into the long-term effects these parasites have on quail populations in the ecoregion may aid landowners in developing affordable and effective conservation strategies.

The effects of habitat, weather, and raptors on northern bobwhite abundance at multiple spatial scales

AbstractRangelands in the southwestern United States represent a current stronghold for northern bobwhite (Colinus virginianus); however, bobwhite populations in rangelands exhibit extreme inter‐annual variability in abundance in relation to fluctuating weather patterns. Recent declining bobwhite population trends within this region have led to the supposition that landscape‐scale processes, such as habitat loss and fragmentation and predation from increased raptor abundance, may be acting in conjunction with weather to reduce bobwhite populations. Our objective was to determine the relative effects of these factors on bobwhite populations in the rangeland environments of Texas and Oklahoma, USA. We obtained publicly available datasets for bobwhite counts (Breeding Bird Survey, state‐agency roadside counts), weather (PRISM), land cover (National Land Cover Database), and raptors (Christmas Bird Counts) for 3 5‐year periods (1990–1994, 1999–2003, 2009–2013). Data were collected at route and landscape scales based on routes within the Rio Grande Plains region of Texas and the Central Mixed Grass Prairie region of Texas and Oklahoma. We used generalized linear mixed models with a backward selection approach to determine top models for each dataset based on scale and ecoregion. Covariate relationships with bobwhite abundance followed expected patterns, with positive relationships with habitat, precipitation, and minimum temperatures and negative relationships with maximum temperatures and raptor abundance. Weather variables were the factors most consistently selected within both regions, while minimum winter temperature was overall the top variable. These relationships occurred within a landscape still containing relatively vast amounts of unfragmented bobwhite habitat (>60% rangeland; >15 million ha). Management within these regions should be focused on retaining habitat at a broad scale, while managing for suitable cover at a local scale to help mitigate weather effects.

Evaluation of seasonal site-level demography and management for northern bobwhite using integrated population models

Understanding the effects of landscape management on northern bobwhite (Colinus virginianus) population growth requires information on seasonal- and stage-specific demographic parameters linked across the full annual cycle. We evaluated site-level seasonal dynamics and population growth of bobwhites in southwest Missouri and compared differences between three extensively and two intensively managed sites from 2016 to 2019. Extensively managed sites were continuous tracts of native prairie. Intensively managed sites were composed of smaller native and non-native grassland units interspersed with strip crops, food plots, and woody field borders. We radio-marked adults and broods to estimate survival and productivity, conducted spring whistle counts to estimate abundance and developed a two-season, two-stage, two-sex integrated population model to estimate population dynamics. The number of young hatched per female-incubated nest was greater on the three extensively managed sites compared to the two intensively managed sites. Six-month period survival of adults during the breeding season was also greater on the three extensively managed sites compared to the two intensively managed sites. One hundred-day juvenile breeding season survival varied among sites and was highest on Talbot, compared to juvenile breeding season survival on the other four study sites. Six-month, non-breeding season period survival was lowest on the two smallest extensively managed sites, Stony Point Prairie and Shelton Conservation Area compared to non-breeding season survival on the other three study sites. Annual changes in bobwhite abundance were weakly correlated with female fecundity, though this positive relationship was stronger on extensively managed sites. Intensively managed sites exhibited low mean fecundity and breeding season adult survival relative to those that resulted in a stable population. Populations across sites declined from 2016 to 2019 and estimates of annual population growth rates overlapped across sites. Differences between observed changes in bobwhite abundance and estimates of observed demographic rates at some sites suggest unmeasured processes such as movement or bias associated with data and model assumptions influenced estimated vital rates. Overall, our integrated population model was an effective tool for understanding site-level seasonal dynamics and population growth of bobwhites. Based on comparisons of demography between extensively and intensively managed sites, we suggest increased native grassland cover managed with prescribed fire, low intensity grazing, and high mowing may increase bobwhite nesting success and breeding season adult survival, however, achieving stable or increasing rates of population growth may also require increased juvenile breeding season and non-breeding season survival.

The development of a convolutional neural network for the automatic detection of Northern Bobwhite Colinus virginianus covey calls

AbstractPassive acoustic monitoring using Autonomous Recording Units (ARUs) is becoming a significant research tool for collecting large amounts of ecological data. Northern bobwhite Colinus virginianus is an economically important game bird whose declining populations are of conservation concern, so efforts to monitor bobwhite abundance using ARUs are being intensified. Yet, manual processing of ARU data is time consuming and often expensive, so developing automatic call detection methods is a key step in acoustic monitoring. We present here the first single species convolutional neural network (CNN) developed purely for automatic bobwhite covey call identification and classification. We demonstrate the value of meaningful data augmentation by including non‐target calls and background noise into our training dataset, as well as evaluating alternative CNN score thresholds and model extrapolation performance. We trained our CNN on 6,682 manually labeled covey calls across three groups of sites within the southeastern USA. Precision and AUC from both CNN classification and individual call detection was high (0.80–0.99), and our model showed strong extrapolation ability across site groups. However, extrapolation performance significantly decreased for sites that were more dissimilar to the training data set if our meaningful data augmentation process was omitted. Our CNN detected significantly more covey calls than manual labeling using Raven Pro software, and processing time was greatly reduced: a single one hour wav file can be now analyzed by the CNN in roughly eight seconds. We also demonstrate using a simple case study that extremely high variability in estimates of bobwhite site occupancy and detection are obtained depending on the method of acoustic data processing (manual versus CNN). Our results suggest that our CNN provides robust and time‐saving analysis of bobwhite covey call acoustic data and can be applied to future research and monitoring projects with high confidence in the performance of the model.

Examining a Habitat-Weather Threshold for Northern Bobwhite Populations in the Southwestern United States

In semiarid portions of the northern bobwhite (Colinus virginianus; hereafter, bobwhite) geographic distribution, weather is a strong driver of interannual abundance. However, the strength of this relationship may depend on habitat amount. Given this habitat–weather dependence, there is likely to be a threshold value for habitat that determines how strongly a bobwhite population responds to weather. Our objective was to evaluate the relationship between habitat amount and the relative influence of weather on bobwhite abundance in Texas and Oklahoma, USA and determine a potential land-cover threshold value. We collected bobwhite abundance and land-cover data from the Breeding Bird Survey and National Land Cover Database, respectively, for 2 time periods which corresponded to historical lows (2012–2013) and highs (2015–2016) of bobwhite abundance within this region. We reclassified land cover into grassland, shrubland, pastureland, cropland, forest, and urban cover, and combined grassland and shrubland categories to represent bobwhite habitat. We used weighted linear regression to model the difference between mean bobwhite abundance between each time period as a function of habitat amount, hypothesizing a positive, linear relationship given the theorized greater influence of weather on populations within higher habitat amounts. To evaluate a potential habitat threshold, we modeled mean bobwhite abundance, for each time period, and all individual land-cover variables using a generalized additive model with a negative binomial distribution. We detected a positive, linear relationship between habitat amount and the difference between high and low bobwhite populations (r2 = 0.30), per our hypothesis. Models of land-cover variables differed between low- and high-abundance time periods. The time period of lower abundance (2012–2013) model included all land-cover variables except cropland and showed significant positive, linear relationships with grass and hay cover, and negative, linear relationships with forest and urban cover. Shrubland cover was the only nonlinear term, increasing to approximately 50–60% cover, then decreasing sharply with increasing cover. Deviance explained for this model was 41.2%. For the period of high abundance (2015–2016) the model explained approximately 25% of the deviance and was reduced to only negative, linear relationships with forest and urban cover. Our results provide some evidence toward the habitat–weather threshold hypothesis. Additionally, while no land-cover values showed a threshold-like relationship with bobwhite abundance, we did document differences in variable selection for each time period. Stressors on bobwhite habitat seem to have a more dramatic impact on bobwhite populations than available habitat, especially in periods of higher abundance, whereas periods of lower

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.

Are northern bobwhites an umbrella species for open‐land birds in Ohio?

AbstractBirds that inhabit open lands such as grasslands and shrublands are rapidly declining across North America. A common practice for multi‐species management is to focus on umbrella species whose habitat requirements overlap with several other species. We evaluated whether the northern bobwhite (Colinus virginianus; bobwhite) could serve as an umbrella species for open‐land birds in Ohio, USA. We related landscape metrics to abundance patterns and assessed whether bobwhite occupancy positively predicts presence of open‐land birds. We combined bird survey data from the second Ohio Breeding Bird Atlas (2006–2011) with land cover data from the 2011 National Land Cover Database (Homer et al. 2015) to construct single‐season N‐mixture models to identify landscape metrics that influence bobwhite abundance. Bobwhite abundance was positively predicted by forest cohesion, percent agriculture, percent barren, and percent grassland. Of the 34 focal species, bobwhites were a significant positive predictor for 12, and a significant negative predictor for 10. The model with only bobwhite occupancy probability as a predictor was the best supported model for only willow flycatcher (Empidonax traillii). These results suggest that bobwhite land cover type requirements are too specialized to meet the needs of broader species guilds, instead affording protection for a narrower range of individual species that share specific habitat requirements with bobwhites. Management for bobwhites may still be able to promote co‐occurrence for declining species across multiple guilds by identifying locations where focused management can create more suitable conditions for species with positive co‐occurrence.

Optimizing conservation in species-specific agricultural landscapes.

Recovery of grassland birds in agricultural landscapes is a global imperative. Agricultural landscapes are complex, and the value of resource patches may vary substantially among species. The spatial extent at which landscape features affect populations (i.e., scale of effect) may also differ among species. There is a need for regional-scale conservation planning that considers landscape-scale and species-specific responses of grassland birds to environmental change. We developed a spatially explicit approach to optimizing grassland conservation in the context of species-specific landscapes and prioritization of species recovery and applied it to a conservation program in Kentucky (USA). We used a hierarchical distance-sampling model with an embedded scale of effect predictor to estimate the relationship between landscape structure and abundance of eastern meadowlarks (Sturnella magna), field sparrows (Spizella pusilla), and northern bobwhites (Colinus virginianus). We used a novel spatially explicit optimization procedure rooted in multi-attribute utility theory to design alternative conservation strategies (e.g., prioritize only northern bobwhite recovery or assign equal weight to each species' recovery). Eastern meadowlarks and field sparrows were more likely to respond to landscape-scale resource patch adjacencies than landscape-scale patch densities. Northern bobwhite responded to both landscape-scale resource patch adjacencies and densities and responded strongly to increased grassland density. Effects of landscape features on local abundance decreased as distance increased and had negligible influence at 0.8 km for eastern meadowlarks (0.7-1.2 km 95% Bayesian credibility intervals [BCI]), 2.5 km for field sparrows (1.5-5.8 km 95% BCI), and 8.4 km for bobwhite (6.4-26 km 95% BCI). Northern bobwhites were predicted to benefit greatly from future grassland conservation regardless of conservation priorities, but eastern meadowlark and field sparrow were not. Our results suggest similar species can respond differently to broad-scale conservation practices because of species-specific, distance-dependent relationships with landscape structure. Our framework is quantitative, conceptually simple, customizable, and predictive and can be used to optimize conservation in heterogeneous ecosystems while considering landscape-scale processes and explicit prioritization of species recovery.

A multispecies approach to manage effects of land cover and weather on upland game birds.

Loss and degradation of grasslands in the Great Plains region have resulted in major declines in abundance of grassland bird species. To ensure future viability of grassland bird populations, it is crucial to evaluate specific effects of environmental factors among species to determine drivers of population decline and develop effective conservation strategies. We used threshold models to quantify the effects of land cover and weather changes in "lesser prairie‐chicken" and "greater prairie‐chicken" (Tympanuchus pallidicinctus and T. cupido, respectively), northern bobwhites (Colinus virginianus), and ring‐necked pheasants (Phasianus colchicus). We demonstrated a novel approach for estimating landscape conditions needed to optimize abundance across multiple species at a variety of spatial scales. Abundance of all four species was highest following wet summers and dry winters. Prairie chicken and ring‐necked pheasant abundance was highest following cool winters, while northern bobwhite abundance was highest following warm winters. Greater prairie chicken and northern bobwhite abundance was also highest following cooler summers. Optimal abundance of each species occurred in landscapes that represented a grassland and cropland mosaic, though prairie chicken abundance was optimized in landscapes with more grassland and less edge habitat than northern bobwhites and ring‐necked pheasants. Because these effects differed among species, managing for an optimal landscape for multiple species may not be the optimal scenario for any one species.

Predation Management and Spatial Structure Moderate Extirpation Risk and Harvest of Northern Bobwhite

ABSTRACTDensity 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. We built a novel population simulation model for the northern bobwhite (Colinus virginianus; bobwhite) that included implicit spatial structure (ingress and egress of individuals), density dependence, and harvest. We used 42 years of data (1970–2012) from a relatively stable population to create and validate the simulation model. We then used this simulation model to predict the effect of meso‐mammal trap and removal, a management action that increases bobwhite fecundity, on population abundance, cumulative harvest through 50 years, and extirpation risk. We conducted a population sensitivity analysis to understand the implications of meso‐mammal trap and removal to populations with varying vital rates. Incorporating ingress and egress of individuals and density dependence improved the understanding of bobwhite population dynamics and reduced the uncertainty about the efficacy of predator management across a range of environmental conditions. Increased number of immigration sources decreased extirpation risk and increased bobwhite abundance. A key outcome of our modeling process was that density‐dependent processes did not fully compensate for harvest. Cumulative harvest through 50 years increased with increasing harvest rate but started to decline when harvest rate was >0.35 for populations with meso‐mammal removal and 0.25–0.30 for populations without meso‐mammal removal. Meso‐mammal removal increased the harvest capacity of populations and produced greater harvest opportunity over time. Meso‐mammal removal also buffered populations from extirpation risk resulting from too few immigration sources. Practitioners often ignore the contribution of immigration and emigration to local demographics or assume density‐independent vital rates; however, recent literature reviews and our study indicate that these processes are important to the understanding of animal ecology and management. In the interest of the conservation of species that are hunted and at risk of extirpation in some geographies, predator management may increase hunter success and be a tool to reduce extirpation risk, although the degree of effectiveness likely varies geographically. This manuscript could serve as a framework for predicting the effects of management on bobwhite at the population level. © 2020 The Wildlife Society.

Nesting Ecology of Northern Bobwhite on a Working Farm

ABSTRACTCreating early successional vegetation on working farms can increase northern bobwhite (Colinus virginianus; hereafter, bobwhite) abundance with little reduction in crop production, but specific effects of field border establishment on bobwhite nesting ecology are not well understood. We monitored bobwhite nesting on a 1,740‐ha working farm with 19% of property managed for early successional vegetation in southeastern North Carolina, USA. We monitored 133 radio‐marked bobwhites from 1 April to 30 September in 2014 and 2015. We modelled nest‐site selection by comparing paired nest and random reference sites and modeled effects of habitat covariates on daily nest survival. Forb, shrub, and native warm‐season grass cover were greater at nest sites than reference sites with forb cover the strongest predictor of nest‐site selection. Bobwhite nested at a greater density in areas managed for fallow vegetation (1 nest/3 ha) than in planted warm‐season grasses and forbs (1 nest/5 ha). The daily nest survival rate over 2 years was 0.964 (SE = 0.007), and was not significantly influenced by any modeled covariate. Naïve nest success (nest successes/total nests) was 46.9%. The importance of forbs as nesting cover indicates bobwhite abundance in areas dominated by row‐crop agriculture may be limited by low nest initiation from a lack of herbaceous nesting cover. Hence, the creation of fallow herbaceous vegetation on working farms should be prioritized to increase bobwhite reproduction within agricultural landscapes. Furthermore, planting warm‐season grasses is not necessary because volunteer forbs and grasses provide as good or better nesting cover and can be less costly to establish. © 2020 The Wildlife Society.

Ecological Discord and the Importance of Scale in Scientific Inquiry

ABSTRACTScale is widely recognized today as an important concept in ecology because the scale of investigation determines the patterns and processes that can be observed. Ecological investigations can produce different outcomes depending on the scale at which observations are made, and ecological disagreements have occurred simply because investigators addressed the same question using different scales. Here I draw on quail research to illustrate the importance of scale in ecological studies and how lack of scale consideration can lead to discord. I use northern bobwhite (Colinus virginianus) as the focal species and discuss 2 areas of investigation (woody‐cover requirements and influence of rainfall) that are characterized by confusion and disagreement but where consideration of scale brings clarity. In the process, I discover 2 formerly unrecognized patterns: northern bobwhite use of woody cover is inversely related with spatial extent of observation, and the influence of rainfall on northern bobwhite abundance decreases with decreasing spatial extent. In both cases, consideration of scale clarifies muddled knowledge and creates a unified framework for management. Future ecological investigations should formulate research questions within a scale framework, provide an explicit statement of scale in methods, and interpret findings within a scale context to help advance wildlife science and management. © 2020 The Wildlife Society.

Multi‐attribute preferences for northern bobwhite habitat restoration among Texas landowners

ABSTRACTNorthern bobwhite (Colinus virginianus) abundance has declined range‐wide over the long term due to factors such as habitat loss and deterioration. Private land management is critical to bobwhite conservation because most bobwhites occur on private lands, but little research has been conducted regarding how private land managers and landowners make decisions about whether and how to restore northern bobwhite habitat. To begin addressing this deficit, we used a choice‐based conjoint approach to determine how Texas, USA, landowners and land managers (surveyed in November 2017) weigh the importance of northern bobwhite hunting opportunities, costs, and labor when making habitat restoration decisions. We also used a latent class analysis to break respondents into segments based on their valuations of these attributes. The results of our latent class analysis indicate that managers and landowners can be grouped into several segments, and most segments do not place a high value on bobwhite hunting opportunities, but instead are more interested in minimizing out‐of‐pocket costs and labor input. Bobwhite habitat restoration programs yielding cost shares ≥50%, labor inputs at ≤30 days/year, and likely coveys flushed per hunting day >4 broadly appealed to landowners; however, ensuring low labor costs was most important, particularly for pragmatic landowners. This indicates that policies minimizing labor inputs and maximizing cost shares may be preferred over increasing hunting opportunities. Finally, we discuss the management preferences and practices of the segment most interested in maximizing bobwhite hunting opportunities and potential outreach strategies for segments of opportunistic and pragmatic landowners who may be persuaded to manage for bobwhite habitat if they perceived this management as economically viable. © 2019 The Authors. Wildlife Society Bulletin Published by Wiley Periodicals, Inc.

Correlates of Habitat Fragmentation and Northern Bobwhite Abundance in the Gulf Prairie Landscape Conservation Cooperative

AbstractThe northern bobwhite Colinus virginianus has experienced range-wide declines over the past several decades, primarily due to habitat loss and habitat fragmentation. As northern bobwhite populations continue to decline, there is a need for studies that address the impact of habitat changes on population persistence at multiple spatial scales. Our goal was to assess changes in habitat and land use related to northern bobwhite declines across multiple spatial scales in Texas, Oklahoma, and Louisiana. We determined northern bobwhite trends for 1972–2012 using Breeding Bird Survey data. At the regional scale, we compared northern bobwhite population trends with road density (2000, 2012), human population (1970–2010), and land use (1974–2012). At the county and local scales, we compared class-level landscape metrics between counties with stable and declining northern bobwhite abundances using Student's t-tests. Northern bobwhite populations decreased from 45.95 ± 1.01 birds/route in 1970 to 11.55 ± 0.64 birds/route in 2012. Road density and human population increased by 3,331.32 ± 66.28 m/km2 and 42,873 ± 8,687 people/county, respectively. Percent pasture and rangeland was relatively stable, as was percent woodland. Alternatively, the percentage of other land (houses, roads, wasteland) increased. At the county scale, Texas and Oklahoma counties with declining northern bobwhite populations had higher road densities, larger patches of pasture, smaller patches of woodland, and larger patches of cropland compared with stable populations. At the local scale, Texas and Oklahoma counties with declining northern bobwhite populations had less woody cover in smaller patches, and fewer but larger patches of herbaceous and bare ground, compared with populations with stable abundance. Therefore, managers can provide woody cover and reduce cropland effects at the local scale to support stable quail populations; however, the large-scale drivers of northern bobwhite decline, which are human population growth and resulting habitat loss, will be an important aspect of northern bobwhite conservation and management in the future.

Elevated parasite burdens as a potential mechanism affecting northern bobwhite (Colinus virginianus) population dynamics in the Rolling Plains of West Texas.

Northern bobwhite quail (Colinus virginianus) are a highly sought-after game bird in the Rolling Plains of West Texas. Unfortunately, bobwhite populations in this area are subject to dramatic fluctuations and have been steadily decreasing over the past several decades. While many factors have been investigated as potential mechanisms of cyclic and declining bobwhite numbers, the effect of parasites on bobwhite populations has historically been undervalued. Between December 2017 and February 2018, we received 21 hunter-shot bobwhite from Garza and Mitchell counties in Texas and found peak caecal worm (Aulonocephalus pennula) and eyeworm (Oxyspirura petrowi) burdens averaging 599 and 44, respectively. These represent the highest average parasite loads we have documented in bobwhite from the Rolling Plains thus far and are coincident with widespread reports of declining bobwhite abundance. These elevated infections also followed a high point in bobwhite populations in the Rolling Plains, and our observations of infection dynamics during this time reflect other instances of potential parasite-induced host mortality. While the sample discussed in this communication is small, our findings highlight the need for additional research into how parasites may affect bobwhite population fluctuations in this region.

Potential impact of neonicotinoid use on Northern bobwhite (Colinus virginianus) in Texas: A historical analysis.

The widespread use of neonicotinoid insecticides in recent years has led to increasing environmental concern, including impacts to avian populations. In Texas and across their range, Northern bobwhite (Colinus virginianus) habitat frequently overlaps cultivated cropland protected by neonicotinoids. To address the effects of neonicotinoid use on bobwhites in Texas, we conducted a historical analysis from 1978–2012 in Texas’ ecological regions using quail count data collected from North American Breeding Bird Survey and Texas Parks and Wildlife Department, and neonicotinoid use data from the U.S. Geological Survey. We considered bobwhite abundance, neonicotinoid use, climate, and land-use variables in our analysis. Neonicotinoid use was significantly (p<0.05) negatively associated with bobwhite abundance in the High Plains, Rolling Plains, Gulf Coast Prairies & Marshes, Edwards Plateau, and South Texas Plains ecological regions in the time periods following neonicotinoid introduction (1994–2003) or after their widespread use (2004–2012). Our analyses suggest that the use of neonicotinoid insecticides may negatively affect bobwhite populations in crop-producing regions of Texas.

Population Responses of the Northern Bobwhite (Colinus virginianus) to Land Use Changes in the Agricultural Landscapes of Ohio, USA

Conversion of natural land cover to agriculture is one of the primary threats to biodiversity worldwide. The Conservation Reserve Program (CRP) and woodlot edge enhancement are two tools used in the United States to provide habitat to wildlife that otherwise have little usable space in intensively agricultural landscapes. CRP provides payments to agricultural producers to replant environmentally sensitive cropland, marginal pasture land, or grassland to conservation practices. The northern bobwhite (Colinus virginianus) is a rapidly declining bird associated with farmland habitat and is often managed for using CRP and woodlot edge enhancement. I studied bobwhites from 2008 to 2010 and 2012–2014 in Brown and Highland Counties, Ohio to document the effects of loss of CRP contracts and addition of woodlot edge enhancement on the rate of change in bobwhite abundance using whistle count surveys. CRP was a strong predictor of bobwhite abundance while woodlot edge enhancement had low predictive power when accounting for loss of CRP. From these results, I tentatively conclude loss of CRP may have significant impacts on this imperiled species, and addition of CRP should be targeted by conservation agencies over woodlot edge enhancement.

An evaluation of northern bobwhite translocation to restore populations

ABSTRACTNorthern bobwhite (Colinus virginianus) populations have been declining in Texas during the last 2 decades. This decline also is occurring in areas with apparently ample habitat such as the Rolling Plains of Texas, USA. The goal of our study was to examine the efficacy of translocating wild‐trapped bobwhites into recently depopulated areas in the eastern Rolling Plains as a method of restoring population size. Our objectives were to document survival (spring‐summer and annual), reproductive efforts, and site fidelity of translocated bobwhites and compare relative abundance of bobwhites between release and control sites to evaluate the efficacy of translocation. We translocated 409 wild bobwhites (n = 186 radio‐marked F) to 2 sites in Shackelford and Stephens counties, Texas, during March 2013 and 2014. Spring‐summer (Mar–Sep) survival ranged between 0.32 and 0.38 (n = 186 bobwhites), and annual survival ranged between 0.19 and 0.23 (n = 186 bobwhites) during 2013–2015. Seventy‐four percent of translocated females that entered the nesting season (i.e., May 1; n = 112 bobwhites) produced a nest, resulting in 125 nests with an apparent nest success of 46.1% and a nesting rate of 1.1 ± 0.1 (SE) nests/female. Site fidelity post‐translocation was moderate to high; 67.7% (n = 44 bobwhites) and 85.1% (n = 40 bobwhites) of translocated bobwhites did not disperse &gt;2 km from their release point during the summers of 2013 and 2014, respectively. Despite this strong demographic performance, relative abundance of bobwhites did not differ between the release and control sites after 2 years as indexed by covey‐call counts (2.7 ± 0.6 vs. 3.0 ± 1.2 coveys/point, respectively; P = 0.71) and helicopter surveys (0.9 ± 0.2 vs. 0.7 ± 0.2 bobwhites/km, respectively; P = 0.64). Thus, translocation of bobwhites failed to increase the bobwhite population beyond that of the control during this study. Future translocation research should aim to increase translocation success by investigating methods for increasing survival during the 1‐month period following translocation (e.g., soft‐release, vitamin E and selenium injections) and for improving site fidelity using conspecific attraction. Future research should incorporate genetic measures to assess genetic contribution of translocated individuals to improve evaluation of translocation success. © 2017 The Wildlife Society.

Quail Management: Issues, Concerns, and Solutions for Public and Private Lands - A Southeastern Perspective

Biologists generally assume that habitat loss, fragmentation, and conversion resulting from changes in landuse are primarily responsible for the nearly rangewide declines in northern bobwhite (Colinus virginianus) abundance noted since at least 1990. Few data-based analyses have addressed this relationship at broad spatial scales. We used data on northern bobwhite abundance from the North American Breeding Bird Survey (BBS; 1966–1999) and county-level landuse from the U.S. Census of Agriculture (COA; 1978, 1987, 1997) to evaluate how 9 landuse variables related to northern bobwhite abundance at the rangewide spatial scale. We also explored the relationship between cropland cover and northern bobwhite abundance by state, physiographic region, and using a moving window approach. Although northern bobwhite abundance typically decreased at the rangewide spatial scale, trends in abundance varied considerably spatially, either exhibiting no trend or increasing in many western and northern portions of this species’ range. While both spatial and temporal patterns in landuse were obvious, there were no clear univariate or multivariate relationships among these variables and bobwhite abundance that could be applied universally across this species’ range. The relationship between cropland cover and northern bobwhite abundance based on physiographic regions was more interpretable than that based on political boundaries (states). When data were used to define spatial patterns between cropland cover and northern bobwhite abundance, spatially consistent and temporally persistent patterns were obtained. We suggest that further research using moving windows of various dimensions, including landuse variables in addition to cropland, and adding several more decades of bobwhite and landuse data is an essential aspect of formulating defensible, spatially explicit strategies for northern bobwhite conservation and management.

Rangewide Trends in Landuse and Northern Bobwhite Abundance: An Exploratory Analysis

Biologists generally assume that habitat loss, fragmentation, and conversion resulting from changes in landuse are primarily responsible for the nearly rangewide declines in northern bobwhite (Colinus virginianus) abundance noted since at least 1990. Few data-based analyses have addressed this relationship at broad spatial scales. We used data on northern bobwhite abundance from the North American Breeding Bird Survey (BBS; 1966–1999) and county-level landuse from the U.S. Census of Agriculture (COA; 1978, 1987, 1997) to evaluate how 9 landuse variables related to northern bobwhite abundance at the rangewide spatial scale. We also explored the relationship between cropland cover and northern bobwhite abundance by state, physiographic region, and using a moving window approach. Although northern bobwhite abundance typically decreased at the rangewide spatial scale, trends in abundance varied considerably spatially, either exhibiting no trend or increasing in many western and northern portions of this species’ range. While both spatial and temporal patterns in landuse were obvious, there were no clear univariate or multivariate relationships among these variables and bobwhite abundance that could be applied universally across this species’ range. The relationship between cropland cover and northern bobwhite abundance based on physiographic regions was more interpretable than that based on political boundaries (states). When data were used to define spatial patterns between cropland cover and northern bobwhite abundance, spatially consistent and temporally persistent patterns were obtained. We suggest that further research using moving windows of various dimensions, including landuse variables in addition to cropland, and adding several more decades of bobwhite and landuse data is an essential aspect of formulating defensible, spatially explicit strategies for northern bobwhite conservation and management. Citation: Peterson, M. J., X. B. Wu, and P. Rho. 2002. Rangewide trends in landuse and northern bobwhite abundance: an exploratory analysis. Pages 35–44 in S. J. DeMaso, W. P. Kuvlesky, Jr., F. Hernandez, and M. E. Berger, eds. Quail V: Proceedings of the Fifth National Quail Symposium. Texas Parks and Wildlife Department, Austin, TX.