Selection of suitable reference genes for normalization of RT-qPCR in three tissues of Northern bobwhite (Colinus virginianus) infected with eyeworm (Oxyspirura petrowi).

BACKGROUND: The Northern bobwhite (Colinus virginianus) is an economically important, and popular game bird in North America. Northern bobwhites have experiencing declines of > 3.5% annually in recent decades due to several factors. The eyeworm Oxyspirura petrowi is a nematode parasite frequently found in the eyes of bobwhites. Although reported frequently in wild bobwhites, there is no research to understand the host-parasite mechanism. Hence, it is important to investigate mechanisms of eyeworm invasion and immune modulation in bobwhite. Cytokine gene expression using RT-PCR is widely used to identify the innate immune response of a host to an infection. METHODOLOGY: In this study, we evaluated ten reference genes (HMBS, RPL19, RPL32, RPS7, RPS8, TATA, SDHA, YWHAZ, GAPDH, and ACTB) for their stability across three tissues (liver, spleen, and caecal tonsils) of control and O. petrowi infected Northern bobwhites. Primer efficiency and reference genes stability were assessed using GeNorm, NormFinder, and BestKeeper. RESULTS: Expression of these reference genes with respect to O. petrowi infection in bobwhites showed RPL32 and HMBS were the most stable genes in the liver, HMBS and SDHA were the most stable genes in the spleen, and HMBS and YWHAZ were equally stable reference genes in the caecal tonsils. CONCLUSION: Based on the geometric mean of all three analyses, our results indicate that the combination of RPL32 and HMBS for the liver, HMBS and SDHA for the spleen, and YWHAZ and HMBS for caecal tonsils might be used as reference genes for normalization in gene expression investigations on Northern bobwhites.

Validation of an enzyme immunoassay for the detection of corticosterone metabolites from northern bobwhite (Colinus virginianus) feces.

Interest in the effects of stressors on wildlife has grown substantially over the past few decades. As this interest has grown, so has the need for minimally invasive and reliable methods for estimating differences in the levels of stress hormones. An enzyme immunoassay using standardized methods was validated for detecting concentrations of corticosterone (cort) metabolites from northern bobwhite fecal samples. Two physiological challenges and one biological challenge were applied to 18 northern bobwhites (nine males and nine females), and the fecal cort metabolite concentrations were compared to baseline levels. The interactions of sex and treatment, treatment and time and sex and time were all significant. Thus, the methods and tools used here were sensitive enough to detect expected changes to the hypothalamo-pituitary-adrenal axis of northern bobwhite.

IMPLICATIONS OF TREATING PARASITIC INFECTION IN NORTHERN BOBWHITE (COLINUS VIRGINIANUS) ON OVERALL HELMINTH LIFE CYCLE.

This study was conducted to determine how reducing the parasite burden in a definitive host may affect the prevalence in intermediate hosts. Here we used the eyeworm Oxyspirura petrowi and cecal worm Aulonocephalus pennula as model species. Northern bobwhite quail (Colinus virginianus) were provided an anthelmintic medicated feed in wild systems because of convincing evidence that these parasites were suppressing their populations. Eyeworm and cecal worm prevalence were measured in Orthopterans, which act as intermediate hosts, using polymerase chain reaction. Individuals were collected from a control site, a site treated for 2 yr, and a site treated for 5 yr. Orthopteran community composition was significantly different among the sites; however, an interaction between subfamily and site was not significant for the eyeworm. There was a significant reduction in eyeworm-infected Orthopterans on the 5-yr site compared with the other 2, suggesting that treatment of a definitive host may indeed affect the prevalence of eyeworms during other life-cycle stages. There was an interaction between the Orthopteran subfamily and the site for the cecal worm, so results were analyzed within each subfamily. A significant reduction in the prevalence of cecal worms was only found in the Cyrtacanthacridinae subfamily on the 5-yr site when compared with the other sites. However, the greatest prevalence in the Gomphocerinae and Oedipodinae subfamilies across all 3 sites was 4.1%. This indicates an unknown degree of cecal worm host specificity. Therefore, conclusions could not be made through the simple assessment of prevalence.

Evaluation of the Chronic Reproductive Toxicity of a Fluorine-Free Firefighting Foam and a Short-Chain Fluorinated Foam to Northern Bobwhite Quail (Colinus virginianus).

The development of fluorine-free firefighting foams has been proposed as a way to reduce the adverse environmental consequences of foams containing per- and poly-fluoroalkyl substances. While there are likely fewer environmental and ecological concerns with these new fluorine-free foams in terms of persistence and bioaccumulation, it is prudent to evaluate the ecotoxicity of these fluorine-free foam products given the absence of data. Oral chronic drinking water exposure studies on adult pairs of northern bobwhite quail (Colinus virginianus) were conducted with a short-chain fluorinated and a fluorine-free foam: Buckeye Platinum Plus C6 and National Foam Avio Green KHC, respectively, at three exposure concentrations (0.01%, 0.1%, and 0.25%). Adults were monitored for survival, growth, and reproductive output; and chicks were monitored for survival and growth. Growth parameters in adult quail were not affected by exposure to the Buckeye or Avio foam. However, liver lipid content was higher in adult males exposed to the Buckeye foam or the Avio foam at the highest exposure concentrations. Chicks were heavier and had higher growth rates after adult exposure to Avio at the highest exposure level (0.25%) and to Buckeye at the two lowest exposure levels but not at the highest exposure level. The two adverse reproductive effects observed from avian exposure to Buckeye were an increased percentage of cracked eggs and earlier arrested embryonic development. Similarly, chronic exposure to Avio also induced earlier arrested embryonic development. These results show that the fluorine-free foams tested did cause toxicity to bobwhite quail, but whether they pose a risk at contaminated sites requires further laboratory and field study and additional exposure data. Environ Toxicol Chem 2024;43:211-221. © 2023 SETAC.

Four Different Surgical Approaches to Vasectomies in Male Texas Bobwhite Quail (Colinus virginianus texanus) and Northern Bobwhite Quail (Colinus virginianus).

Vasectomies render a male sterile and have been used for various management purposes, including conservation efforts. This report evaluated 4 different surgical approaches (external approach, internal approach with dissection, internal approach with cautery, and internal approach caudally) to perform 177 vasectomies in Texas bobwhite (Colinus virginianus texanus; n = 171) and northern bobwhite quail (Colinus virginianus; n = 6) in a field setting. Birds were not randomized into groups for the different approaches. Survival was recorded in 83% (147/177) of the birds. The most common cause of death was hemorrhage from the common iliac vein due to damage during the surgical procedure. Other causes for death included transection of the ureter, parasitism, euthanasia, and undetermined causes. The approach that had the highest survival rate (89.8%, 132/147) was the internal approach with cautery, and based on these results the authors recommend this approach for vasectomies in Texas and northern bobwhite quail.

EXPLORING A PLANT-DIVERSITY HYPOTHESIS TO EXPLAIN HELMINTH PREVALENCE IN NORTHERN BOBWHITE (COLINUS VIRGINIANUS) IN TEXAS, USA.

Helminths, in particular eyeworms (Oxyspirura petrowi) and cecal worms (Aulonocephalus pennula), may be a factor influencing northern bobwhite (Colinus virginianus) populations in Texas. Previous research has shown a discrepancy in helminth infections between the Rolling Plains and Rio Grande Plains of Texas, US, potentially caused by differences in intermediate host distribution and abundance. We explored an alternative hypothesis centered on plant diversity, given that many plants possess phytochemicals with anthelmintic properties. 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 and intensity. We conducted a literature review of plant diversity, anthelmintic plants, and bobwhite diet in Texas to explore this hypothesis. We also quantified the relationship between helminth prevalence in bobwhites and latitude. We documented trends for higher plant species richness, greater number of anthelmintic plants, and more diverse bobwhite diet in the Rio Grande Plains compared to the Rolling Plains. In addition, we documented a trend for increasing helminth prevalence with latitude for eyeworms but not cecal worms. Our study provides circumstantial evidence supporting the plant-diversity hypothesis and warrants experimental testing.

MOLECULAR IDENTIFICATION OF INSECT INTERMEDIATE HOSTS WITH POTENTIAL PARASITE TRANSMISSION TO THE DEFINITIVE HOST NORTHERN BOBWHITE (COLINUS VIRGINIANUS).

Grassland birds have been declining substantially for the past several years. Habitat loss, degradation, and fragmentation as well as climate change are all thought to be the main drivers of the decline. However, as the declines continue to accelerate, it is becoming imperative to examine other factors that may contribute to population fluctuations. The nematodes Oxyspirura petrowi, Aulonocephalus pennula, and Physaloptera sp. are commonly found infecting northern bobwhite (Colinus virginianus), a game species of economic importance, and all 3 nematodes use insects as an intermediate host. Here we used polymerase chain reaction techniques to determine the occurrence of the 3 nematodes in 7 insect orders to uncover epidemiological patterns of the greatest potential for transmission to northern bobwhite. Insects were collected from March through September using sweep nets and pitfall traps. An R × C chi-squared test with Monte Carlo simulation was used to determine differences in the occurrence of the parasites across taxa and time. The results of the statistical analysis showed the nematodes are predominantly found in the order Orthoptera, and A. pennula and Physaloptera sp. showed epidemiological patterns in insects. However, no such pattern was observed with O. petrowi. An explanation for the lack of epidemiological pattern in O. petrowi is proposed and the diversity of known insect hosts of the 3 nematodes is increased.

Storage time and temperature of filter paper strips affect anti-West Nile virus antibody detection in 2 galliform species.

The effects of filter paper strip (FPS) storage time and temperature on antibody detection are poorly understood despite widespread use in wildlife research. We collected sera and FPSs from 23 wild turkeys (Meleagris gallopavo) and 20 northern bobwhites (Colinus virginianus) experimentally infected with West Nile virus (WNV) to compare FPS storage methods with WNV plaque reduction neutralization test (PRNT) sensitivity. FPS storage methods included: immediate elution after drying, and storage at -20°C for 3 mo, -20°C for 6 mo, room temperature (RT) for 3 mo, and RT for 6 mo prior to elution. FPS eluates and sera were co-titrated to determine endpoint antibody titers, which were compared between FPS sera eluted immediately and sera, and among FPS eluates that underwent different storage conditions. Antibody titers were ~4-fold less in FPS sera eluted immediately versus sera, and dropped more frequently below PRNT detection threshold in northern bobwhites, which had ~10-fold lower serum antibody titers than wild turkeys. Antibody titers were lower in FPS samples stored at RT and for 6 mo. WNV serologic surveys may result in falsely low seroprevalence estimates if FPSs are stored at RT for ≥ 3 mo before elution.

Development of a mechanistic model for analyzing avian reproduction data for pesticide risk assessment.

Mechanistic effect models are increasingly recommended as tools for refining evaluations of risk from exposure to pesticides. In the context of bird and mammal risk assessments, DEB-TKTD models have been recommended for characterizing sublethal effects at lower tiers. However, there are currently no such models. Currently, chronic, multi-generational studies are performed to characterize potential effects of pesticides on avian reproduction, but it is has not been established to what extent results from these studies can inform effect models. Here, a standard Dynamic Energy Budget (DEB) model was extended to account for the avian toxicity endpoints observed in regulatory studies. We linked this new implementation to a toxicological module to capture observed pesticide effects on reproduction via a decreased efficiency of egg production. We analysed ten reproduction studies with five different pesticides conducted with the mallard (Anas platyrhynchos) and the northern bobwhite (Colinus virginianus). The new model implementation accurately distinguished between effects on egg production from direct mechanism of toxicity and from food avoidance. Due to the specific nature of regulatory studies, model applicability for risk refinement is currently limited. We provide suggestions for next steps in model development.

Validation of an LC-MS/MS method for assessment of fenbendazole sulfone drug residue in northern bobwhite liver.

The Northern Bobwhite (Colinus virginianus) is an economically important game bird within the Rolling Plains Ecoregion. Within this region, bobwhite is experiencing extreme cyclic population fluctuations which are resulting in a net decline in total population. It is suspected that within this region two helminth parasites, an eyeworm (Oxyspirura petrowi) and a cecal worm (Aulonocephalus pennula), are contributing to this phenomenon. However, this has been difficult to study as the primary mode of investigation would be the deployment of anthelmintic treatment. Unfortunately, no registered treatments for wild bobwhite currently exist. Thus, utilizing an anthelmintictreatment for wild bobwhite would require registration of that treatment with the U.S. Food and Drug Administration (FDA). As bobwhite are game birds that are hunted, they are considered food-producing animals to the FDA, and as such require the assessment for the withdrawal of the drug residues to be assessed for human food safety. In this study, we optimized and validated a bioanalytical method for the quantification of fenbendazole sulfone in bobwhite following the U.S. FDA Center for Veterinary Medicine Guidance for Industry #208 [VICH GL 49 (R)] for assessment of fenbendazole sulfone drug residue in Northern bobwhite liver. The official method for quantifying fenbendazole sulfone in domestic chicken (Gallus gallus) was adapted for use in bobwhite. The validated method quantitation range is 2.5-30 ng/mL for fenbendazole with an average recovery of 89.9% in bobwhite liver.

Climate alters the movement ecology of a non-migratory bird.

Global climate change is causing increased climate extremes threatening biodiversity and altering ecosystems. Climate is comprised of many variables including air temperature, barometric pressure, solar radiation, wind, relative humidity, and precipitation that interact with each other. As movement connects various aspects of an animal's life, understanding how climate influences movement at a fine-temporal scale will be critical to the long-term conservation of species impacted by climate change. The sedentary nature of non-migratory species could increase some species risk of extirpation caused by climate change. We used Northern Bobwhite (Colinus virginianus; hereafter bobwhite) as a model to better understand the relationship between climate and the movement ecology of a non-migratory species at a fine-temporal scale. We collected movement data on bobwhite from across western Oklahoma during 2019-2020 and paired these data with meteorological data. We analyzed movement in three different ways (probability of movement, hourly distance moved, and sinuosity) using two calculated movement metrics: hourly movement (displacement between two consecutive fixes an hour apart) and sinuosity (a form of tortuosity that determines the amount of curvature of a random search path). We used generalized linear-mixed models to analyze probability of movement and hourly distance moved, and used linear-mixed models to analyze sinuosity. The interaction between air temperature and solar radiation affected probability of movement and hourly distance moved. Bobwhite movement increased as air temperature increased beyond 10°C during low solar radiation. During medium and high solar radiation, bobwhite moved farther as air temperature increased until 25-30°C when hourly distance moved plateaued. Bobwhite sinuosity increased as solar radiation increased. Our results show that specific climate variables alter the fine-scale movement of a non-migratory species. Understanding the link between climate and movement is important to determining how climate change may impact a species' space use and fitness now and in the future.

A Helminth Survey of Northern Bobwhite Quail (Colinus virginianus) and Passerines in the Rolling Plains Ecoregion of Texas.

The Northern bobwhite quail (Colinus virginianus) is a popular game bird that has been experiencing a well-documented decline throughout Texas since the 1960s. While much of this decline has been attributed to habitat loss and fragmentation, recent studies have identified other factors that may also contribute to decreasing quail populations. Parasites, in particular, have become increasingly recognized as possible stressors of quail, and some species, particularly the eyeworm (Oxyspirura petrowi) and cecal worm (Aulonocephalus pennula) are highly prevalent in Texas quails. Eyeworm infection has also been documented in some passerines, suggesting helminth infection may be shared between bird species. However, the lack of comprehensive helminth surveys has rendered the extent of shared infection between quail and passerines in the ecoregion unclear. Thus, helminth surveys were conducted on bobwhite, scaled quail (Callipepla squamata), Northern mockingbirds (Mimus polyglottos), curve-billed thrashers (Toxistoma curvirostre), and Northern cardinals (Cardinalis cardinalis) to contribute data to existing parasitological gaps for birds in the Rolling Plains ecoregion of Texas. Birds were trapped across 3 counties in the Texas Rolling Plains from March to October 2019. Necropsies were conducted on 54 individuals (36 quail and 18 passerines), and extracted helminths were microscopically identified. Nematode, cestode, and acanthocephalan helminths representing at least 10 helminth species were found. Specifically, A. pennula and O. petrowi had the highest prevalence, and O. petrowi was documented in all of the study species. This research adds to the body of knowledge regarding parasitic infections in quail and passerines of the Rolling Plains ecoregion and highlights the potential consequences of shared infection of eyeworms among these bird species.

Assessment of the helminth fauna in northern bobwhites (Colinus virginianus) occurring within South Texas.

Populations of northern bobwhites (Colinus virginianus; hereafter bobwhite) have been declining across their geographic range in North America, prompting consideration of the role parasites may play. We conducted this study to learn about the helminth fauna in South Texas, a region that supports a sustainable bobwhite population. Helminths were examined from 356 bobwhites collected during the 2014-2015 (n = 124) and 2015-2016 (n = 232) hunting seasons, when increasing trends in precipitation were observed in comparison with the previous two years. Ten helminth species were found, consisting of 14,127 individuals. Of these, all are heteroxenous parasites and three are pathogenic (Dispharynx nasuta, Tetrameres pattersoni and Oxyspirura petrowi). Aulonocephalus pennula numerically dominated the component community (81% prevalence, 99% of the total helminths found), whereas each of the remaining species occurred rarely (≤9% prevalence) and contributed few individuals (≤0.4%) to the helminth community. Prevalence and abundance of A. pennula were not influenced by host age, sex or body mass, but abundance was higher during the 2014-2015 than the 2015-2016 hunting season. Our findings indicate that the helminth community in bobwhites from South Texas can vary during long-term, highly variable precipitation conditions and these communities are more similar to those found in the Rolling Plains of Texas than those found in the eastern part of the bobwhite's geographic range in the US.

Experimental West Nile Virus Infection in Northern Bobwhite Quail (Colinus virginianus).

West Nile virus (WNV) has been implicated in regional declines of numerous North American bird species, although its potential impact upon many species, including some game birds, remains unknown. Specifically, information about susceptibility to infection and infection outcome are crucial to assessing health risks. Northern bobwhite quail (Colinus virginianus) are a popular and common game bird across much of the United States, as well as in captive breeding programs and as backyard birds. Two age groups of bobwhites were subcutaneously inoculated with WNV and euthanatized on 15 days postinoculation (DPI). Three of 10 inoculated 5-wk-old and 4/10 inoculated 15-wk-old birds developed detectable viremia titers during 1-5 DPI, with low peak titers (101.7-103.0 plaque-forming units [PFU]/ml). Three of 10 inoculated 5-wk-old and 1/10 inoculated 15-wk-old birds shed low viral titers (peak 100.7-101.8 PFU/swab) either orally or cloacally or both for limited periods from 2 to 6 DPI. All inoculated birds (n = 20) remained apparently healthy and seroconverted by 15 DPI. No infectious virus was detected in select tissues: heart, kidney, brain, skeletal muscle, spleen (15-wk-old group only), and feathers from any of the bobwhites. No sham-inoculated, contact control birds (n = 8) became viremic or had virus isolated from tissues or swabs. The most consistent microscopic lesion was minimal to mild, lymphoplasmacytic myocarditis (6/10 in 5-wk-olds; 5/10 in 15-wk-olds). Immunohistochemical labeling was most often in macrophages in spleen and bone marrow, likely reflective of clearance of infection. There were no statistically significant differences in the peak viremia and shedding titers between age groups and no differences in the development of WNV-associated lesions between the two age groups. These results suggest that WNV is unlikely to pose a health risk to bobwhites and that bobwhites likely are an incompetent reservoir host species in WNV transmission.

Infección experimental por el virus del Nilo occidental en codornices de Virginia (Colinus virginianus). El virus del Nilo Occidental (con las siglas en inglés) se ha visto implicado en la disminución regional de numerosas especies de aves en América del Norte, aunque se desconoce su impacto potencial sobre muchas especies, incluidas algunas aves de caza. Específicamente, la información sobre la susceptibilidad a la infección y el resultado de la infección es crucial para evaluar los riesgos para la salud. La codorniz de Virginia (Colinus virginianus) es un ave de caza popular y común en gran parte de los Estados Unidos, así como en programas de cría en cautiverio y como aves de traspatio. Dos grupos de codornices de diferentes edades fueron inoculadas por vía subcutánea con el virus del Nilo Occidental y fueron sacrificadas 15 días después de la inoculación (DPI). Tres de diez aves inoculadas de cinco semanas y cuatro de diez aves inoculadas de 15 semanas desarrollaron títulos de viremia detectables durante uno a cinco días después de la inoculación, con bajos títulos durante la cima de la curva (101.7­103.0 unidades formadoras de placa [PFU]/ml). Tres de diez aves inoculadas de cinco semanas de edad y una de diez aves inoculadas a las 15 semanas de edad mostraron títulos virales bajos (pico 100.7­101.8 PFU/hisopo) ya sea por vía oral, cloacal o ambas durante períodos limitados de dos a seis días después de la inoculación. Todas las aves inoculadas (n = 20) permanecieron aparentemente sanas y mostraron seroconversión a los 15 días después de la inoculación. No se detectó ningún virus infeccioso en tejidos seleccionados: corazón, riñón, cerebro, músculo esquelético, bazo (solo en el grupo de 15 semanas de edad) y plumas de cualquiera de las codornices. Ninguna ave no inoculada o de control por contacto (n = 8) se volvió virémica o mostró aislamiento viral de los tejidos o hisopos. La lesión microscópica más consistente fue miocarditis linfoplasmocítica de mínima a leve (6/10 en aves de cinco semanas; 5/10 en aves de 15 semanas). La tinción inmunohistoquímica se observó con mayor frecuencia en macrófagos del bazo y la médula ósea, lo que probablemente refleja la eliminación de la infección. No hubo diferencias estadísticamente significativas en el pico de viremia y los títulos de eliminación entre los grupos de edad y no hubo diferencias en el desarrollo de lesiones asociadas con el virus del Nilo Occidental entre los dos grupos de edad. Estos resultados sugieren que es poco probable que el virus del Nilo Occidental represente un riesgo para la salud de las codornices de Virginia y que estas aves probablemente sean una especie hospedadora reservorio incompetente en la transmisión del virus del Nilo Occidental.

Complete Blood Cell Count and White Blood Cell Counting Method Comparison in 49-day-old Bobwhite Quail (Colinus virginianus).

The northern bobwhite quail (Colinus virginianus) is a game bird experiencing decline throughout much of its range. There are limited species-specific and age-specific hematologic data for bobwhite quail. Complete blood cell counts in eighteen 49-day-old captive-raised quail of unverified sex were used to contribute data to reference intervals for the species as juvenile animals. Values for packed cell volumes, total solids, red and white blood cell counts, and white cell differential calculations were recorded for each animal. Bobwhite quail of this age were found to be primarily lymphocytic, but considerable variability was observed. White blood cell counts were obtained by estimates from blood smears and Phloxine B stain. White blood cell counts performed with ×1000 magnification did not compare well with other white blood cell methods, including Phloxine B stain.

Validation of a noninvasive technique to quantify stress in northern bobwhite (Colinus virginianus).

Examination of the endocrine system through non-invasive fecal sampling may improve population management more than using demographic indicators alone. By addressing the physiological mechanisms that are influencing fitness, management actions can be proactively developed to alleviate stressors. Proactive determination of vulnerable populations is critical for species of concern, such as the Northern Bobwhite (Colinus virginianus), which have suffered decades of population decline. We validated an assay to noninvasively measure the adrenocortical response of captive reared bobwhite through fecal corticosterone metabolites (FCM). All individuals received three sequential 48-hour treatments in which samples were collected every 4 hours, including a reference period, an adrenocorticotropic hormone (ACTH) challenge and a biological stressor (exposure to a hunting dog). Reference FCM values had a mean concentration of 16.75 pg/mg (95% CrI: 13.68, 19.91) with adrenocortical activity increasing by 73% for the duration of the ACTH challenge (29.00 pg/mg; CrI: 25.01, 33.78). FCM concentrations remained similar to that of the reference levels during the biological stressor (16.56 pg/mg; CrI: 13.33, 19.92). Our study validates the use of feces to detect changes in FCM levels in our subject species but also demonstrates the complexity of FCM and the importance of both physiological and biological validation prior to field implementation.

Molecular Identification of Oxyspirura Petrowi Intermediate Hosts by Nested PCR Using Internal Transcribed Spacer 1 (ITS1).

Recently, the heteroxenous eyeworm, Oxyspirura petrowi, has gained attention due to its prevalence in the declining game bird, Northern bobwhite (Colinus virginianus), but the intermediate hosts of many nematodes remain unknown. However, identifying the intermediate host of O. petrowi with traditional techniques would be difficult and time-consuming, especially considering there are more than 80 potential orthopteran hosts just in Texas. To screen a large number of samples quickly and effectively, primers for nested PCR (nPCR) were developed using the internal transcribed spacer 1 (ITS1) region. Then the nPCR was used to identify which of the 35 species collected from the Order Orthoptera were potential intermediate hosts of O. petrowi. With this technique, 18 potential intermediate hosts were identified. Later, we collected live specimens of species that tested positive to confirm the presence of larvae, but larvae were not found in the live specimens, nor in the extra tissue of the species that had tested positive for O. petrowi DNA. Despite this, this study demonstrated that nPCR is more sensitive than traditional techniques and can be a valuable tool in determining the intermediate hosts of parasites.

Nonconsumptive effects of hunting on a nontarget game bird.

Human hunting activity and disturbance can significantly impact prey species through both consumptive and nonconsumptive effects. The nonconsumptive effects of rabbit hunting on Northern Bobwhite (Colinus virginianus; hereafter, bobwhite) are currently unknown. Increased perceived risk of predation by bobwhite during rabbit hunting events may elicit antipredator responses among bobwhite that impact fitness via changes in behavior that ultimately impact population growth.We estimated the nonconsumptive effects of rabbit hunting on bobwhite behavior using telemetry across varying rabbit hunting intensities. Movements were analyzed using Bayesian hierarchical modeling with a before-after-control-impact (BACI) design to determine the effect of rabbit hunting on bobwhite.We observed an overall reduction in bobwhite movement in the presence of rabbit hunting, with a 38% (Posterior Overlap = 0.01) increase in bobwhite step length in the absence of rabbit hunting. We also observed bobwhite maintaining closer proximity to hardwood and escape cover under high rabbit hunting intensity, with a 59% (Posterior Overlap = 0.03) increase in distance from hardwood and a 28% (Posterior Overlap = 0.14) increase in distance from escape cover when rabbit hunting was removed. Synthesis and applications. Heightened antipredator behavior through decreased movement may assist with bobwhite predator avoidance. However, decreased movement and increased use of poor habitats may also have negative effects as a result of reduced foraging time or increased susceptibility to other predators. Future research should attempt to quantify the effect of decreased movement on bobwhite fitness through the evaluation of foraging time and survival in order to continue to improve management efforts for the species.

Helminth community and host dynamics in northern bobwhites from the Rolling Plains Ecoregion, U.S.A.

One hundred and sixty-one northern bobwhites (Colinus virginianus; hereafter 'bobwhite') were examined from the Rolling Plains ecoregion of Texas and western Oklahoma from 2011 to 2013. Complete necropsies yielded 13 species, of which two are new host (Gongylonema phasianella) and region (Eucoleus contortus) records and three (Dispharynx nasuta, Tetrameres pattersoni and Oxyspirura petrowi) are known to cause morbidity and mortality. Of the species found, Aulonocephalus pennula commonly occurred, Oxyspirura petrowi was intermediate in prevalence, and the remaining species were rare. Species richness was similar compared to studies from the southeastern U.S., but higher than studies from the same region. In addition, 12 of the 13 species were heteroxenous helminths, supporting the theory that heteroxenous helminths in semi-arid regions are more successful than monoxenous helminths. Prevalence and abundance of A. pennula and O. petrowi were higher in adult bobwhites than in juveniles. Abundance of A. pennula and O. petrowi was higher at southern locations compared to northern locations in the study area. Our study is the first to provide a current assessment of the bobwhite helminth community across the Rolling Plains ecoregion of the U.S.

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.