Quail Species Research Articles

Appendix A: Strategic Plan for Quail Management and Research in the United States: Introduction and Background

I assessed the current, broad-scale status of populations, research, and management for 6 species of quail in the U.S., and used this information as an introduction, background, and justification for a national strategic planning effort for quail management and research. Long-term (1960-89) trends determined from Christmas Bird Count data indicate that California quail (Callipepla californica), northern bobwhite (Colinus virginianus), and scaled quail (Callipepla squamata) populations have undergone (P < 0.05) declines. Geographic distribution of mountain quail (Oreortyx pictus) has contracted dramatically in the northeastern portion of this quail's range. Neither Gambel's (C. gambelii) nor Montezuma quail (Cyrtonyx montezumae) showed evidence of long-term increases or decreases. Wildlife professionals have apparently paid scant attention to quail in the U.S. during the past 10 years. A recent survey of Wildlife Review indicated <0.2% of the publications pertained to quail. During 1990, < 1.0% of Federal Aid in Wildlife Restoration funds were allocated to quail-related projects. Habitat management by the private sector is apparently having little broad-scale impact on bobwhite populations. Contemporary quail management efforts in the U.S. are clearly in the doldrums and in dire need of leadership from professionals with a creative vision for solving problems caused by changing land-use practices. These factors point to a critical need for a national strategic planning effort to develop a comprehensive, coordinated program for quail management and research. An outline of the structure of the Strategic Planning Workshop that was held at Quail III is provided. Specific management and research problems and associated strategies for solving them are available in Issues and Strategies, which follows (page 181).

Montezuma Quail Management in Arizona: Addressing Needs of a Consistent, Dedicated Public With a Variable, Inconsistent Resource

Montezuma quail (Cyrtonyx montezumae) are unique among species of quail in habitat, diet, and behavior; these distinctions combined with an exotic appearance, and distribution in warmer climates in the United States have made them a popular game bird among a dedicated cadre of upland bird hunters. Montezuma quail are not, however, unique in population fluctuations which are largely affected by climatic factors. The history of harvest management for Montezuma quail in Arizona has generally been one of increasing season lengths and bag limits since the first 2-day hunt in 1960. There have, however, been several instances when season dates and bag limits have been changed, largely in response to public demand from individuals and groups that believed efforts to reduce harvest would protect populations and reduce fluctuation of bird numbers. Research directed specifically at the influence of harvest on Montezuma quail populations has found quail numbers fluctuate independent of potential harvest levels. Density-dependent survival, compensatory mortality, and self-regulating hunter numbers are often invoked to explain fluctuation of quail numbers independent of harvest regulations. We reviewed current literature relative to these issues and investigated Montezuma quail harvest characteristics to inform management options. Hunter numbers, based on hunter questionnaire data collected between 1987 and 2009, had greater influence (r2 1⁄4 0.616) on Montezuma quail harvest than either birds/day (r2 1⁄4 0.474), or days/hunter (r2 1⁄4 0.229) suggesting restricting hunter numbers would affect harvest more than reducing bag limits or season length. The average Montezuma quail hunters in Arizona harvested , 2 birds/day, , 6 birds/season, and hunted , 4 days/season. Dedicated hunters typical of those seeking harvest restrictions are not ‘average’ hunters and often have inflated views of the impact of hunting on annual fluctuations in bird numbers. Efforts to control harvest commensurate with perceived bird populations would be ineffective at maintaining reliable bird numbers and would be inconsistent with the current state of knowledge relative to effects of hunting on Montezuma quail numbers. Alternative management options including increasing public information and education efforts may be more effective at satisfying the needs of the dedicated community of Montezuma quail enthusiasts.

Causes and Consequences of Mixed-Species Coveys of California and Gambel’s Quail and Their Hybrids

California (Callipepla californica) and Gambel’s quail (C. gambelii) hybridize where their distributions overlap. Outside of the area of overlap, pairs are known to form within the covey. I observed two mixed-species coveys within the hybrid zone and examined if pairing occurred within the coveys. I compared hatching success and survival of chicks between resident within-covey pairs to immigrant pairs. Isolated coveys could become inbred, given that choice of conspecific mate may be constrained by small population size. I measured relatedness between quail for each individual that paired within the covey, and tested whether it was more or less related to its mate than to other individuals in the covey of the same and opposite sex. The hybrid zone between C. californica and C. gambelii appears to be bounded by ecological forces rather than genetic incompatibility. Clinal allelic and plumage trait differences between C. californica and C. gambelii map closely into the ecotonal area of hybridization. Quail species have fluid geographical distributions but extraordinarily plastic mating systems. This dynamic may help explain why quail have a higher incidence of hybridization than most other bird species.

The Forgotten Quail Decline: The Plight of Scaled Quail in Texas

Several quail species are experiencing range-wide declines in the United States. The northern bobwhite (Colinus virginianus) has garnered the most attention, both from a research and conservation perspective. The bobwhite decline in Texas, has resulted in considerable time and effort being devoted to research and management on the species due to its status as a highly popular and economically important game bird. This attention has been beneficial to bobwhite conservation and management but, an unfortunate consequence of this focus has been neglect of the scaled quail (Callipepla squamata) that has been declining at even a more alarming rate. Scaled quail, according to Breeding Bird Survey (BBS) data, have declined at a rate of 5.1% per year in the Tamaulipan Biotic Province (southern Texas), the greatest of any region surveyed in its geographic range. Anecdotal reports of landowners have long noted the gradual disappearance of scaled quail and concomitant replacement with northern bobwhite throughout southern Texas, beginning since about the 1990s. Analysis of BBS data provides evidence for this replacement. Percent of quail detections in the core of the scaled quail range in the Tamaulipan Biotic Province were 80:20 (scaled quail: bobwhite) during the 1960s but currently represent about 5:95. In addition, the range of scaled quail has been contracting, moving progressively west with time. The species is no longer detected on the easternmost BBS routes in southern Texas.

A Brief History of Insecticides and Quail

Humans have employed chemical methods of pest control since the earliest days of agriculture and these substances have affected native wildlife, including quail and other gamebirds (Galliformes), to varying degrees. Several quail species have experienced steep population declines over the past several decades and insecticides may be a contributing factor. Quail are also known to use agricultural habitat for nesting and foraging purposes and are therefore likely to encounter elevated levels of insecticidal chemicals in the soil, vegetation, and insect biomass in that environment. The first commercially available insecticides appeared in the early 1900s with the introduction of arsenic-based compounds (arsenicals). Chemical engineering during World War II resulted in arsenicals being replaced with synthetically produced insecticides such as organochlorine, carbamate, and organophosphate compounds over several decades. Many of these substances have been shown to increase mortality rate, alter behavior, and produce severe reproductive complications in quail, both in the lab and the field. Today, the world’s most popular insecticides, neonicotinoids, are being reevaluated for environmental safety following reports that they may be affecting nontarget wildlife. This review examines the types of insecticides that have been used in the United States, how quail could be exposed to these substances, and how they may have contributed to declining quail populations.

Changes in Habitat Use of Montezuma Quail in Response to Tree Canopy Reduction in the Capitan Mountains of New Mexico

Montezuma quail (Cyrtonyx montezumae) are unique among quail with respect to clutch size, diet, covey dynamics, and habitat use. With the exception of a few notable early studies, there is relatively little information on the ecology of Montezuma quail. Pervious research has indicated that one of the primary habitats utilized by Montezuma quail is pinyon–juniper (Pinus spp.–Juniperus spp.) woodlands. Throughout many areas of the southwestern United States, pinyon–juniper woodlands are often targeted for thinning projects. Many studies have been conducted on the amount of canopy cover needed by other quail species. However, data on characteristics of their preferred habitat in many of the mountains they inhabit is limited in the literature and no data are currently published on their response to thinning projects. Therefore, studies are warranted to fill in these missing data, which will increase our knowledge about the habitat requirements of Montezuma quail and allow us to make informed decisions about thinning projects in areas occupied by Montezuma quail. The goal of this research was to evaluate Montezuma quail responses to common silvicultural practices, specifically pinyon–juniper thinning in the Capitan Mountains of New Mexico. Results of our project indicated that Montezuma quail selected for sites that had been thinned to reduce canopy cover to a 30–40% mosaic. Selection for this habitat was much higher than selection for the surrounding area, which consisted of ≥70% canopy cover (Manly–Chesson Selectivity Index = 1.68). Overall, this study yields vital information for managers considering implanting thinning projects in Montezuma quail habitat.

Population Response of Three Quail Species to Habitat Restoration in South Texas

Maintaining and increasing usable space is paramount for maintaining and increasing wild quail. Aside from weather and other factors that can temporarily reduce densities, range-wide, no factor has as much influence on quail populations as the amount of habitat present across the landscape. In the field of quail management, ‘‘bad news’’ is the norm, as many articles begin by explaining how a select species has declined. Here we provide good news and use 4 empirical examples of population increases for 3 quail species following creation of usable space and restoration of patch connectivity. From 2008–2014, a suite of independent projects aimed at increasing usable space for quail was initiated across South Texas. These projects included 3 focused on northern bobwhites (Colinus virginianus), 1 focused on scaled quail (Callipepla squamata), and 1 landowner-executed project focused on Montezuma quail (Cyrtonyx montezumae). Through the correction of attributes limiting habitat, bobwhite numbers increased 22–378% across 2 studies. On one particular study site, native grassland restoration resulted in the colonization of bobwhites from adjacent areas to 1 bobwhite/1.2 ha from nearly 0. For scaled quail in South Texas, reducing buffelgrass standing crop via grazing from about 2,240 kg/ha to 1,008 kg/ha resulted in the recolonization of a previously unoccupied habitat patch to a density of 1 scaled quail/6 ha. Finally, clearing monotypic stands of the invasive native plant, ash juniper (Juniperus ashei) in the Edwards Plateau of Texas, resulted in the reestablishment of native grasses and forbs and thus recolonization by Montezuma quail from nearby areas. Although habitat restoration and management can be a painstaking and lengthy process, addressing limiting factors to quail occupancy is the only known way to increase wild quail populations. We hope that highlighting these particular studies will provide inspiration to those interested in restoring and increasing quail across the US.

Use of Portable Infrared Cameras to Facilitate Detection and Capture Success of Montezuma Quail

Survey and trapping methods for Montezuma quail (Cyrtonyx montezumae) require means not traditionally used for other quail species (e.g., northern bobwhite, Colinus virginianus). Trapping Montezuma quail is most effective using pointing dogs at night when coveys can be located and captured by net during roosting. However, reduced visibility at night, cryptic coloration of plumage, and behavioral adaptive stillness reduce detection rates and increase accidental flushing of birds while searching for roost locations. Forward-looking infrared (FLIR) cameras have been used to aid in detection of cryptic wildlife, including avifauna roosting sites. We conducted 25 survey and night-trapping sessions for Montezuma quail in southeast Arizona using a combination of trained pointing dogs and a portable FLIR camera. Detection of coveys on a roost was less successful when ambient climate conditions were freezing (below 3.88 8C), when residual heat signatures from surrounding soils and rocks were greater than 18.33 8C, or when density of grass cover exceeded 40% and the distance to covey was . 2.5 m. The small thermal signatures of quail were often obstructed by vegetative cover or confused with residual thermal signatures reflected by inanimate objects (e.g., rocks, bare ground). Successful detection of coveys combining the use of dogs and FLIR before trapping was 6.06%. Trapping success and detection of coveys with FLIR was improved when used with radiotelemetry and coveys which included radio-marked individuals. Proper tuning of FLIR camera sensitivity to a limited thermal bandwidth, or isotherm range, may effectively narrow covey locations approximated by a pointing dog. The FLIR camera was of limited benefit when actively trapping coveys with dogs and a team of 2–3 people, but may be beneficial for non-invasive monitoring and estimating covey size of marked birds on roosts in landscapes with reduced vegetative cover.

Closing Remarks: Pieces of the Puzzle, Circles in the Stream

Individually and collectively, we continue to add pieces to the quail management and research puzzle. Nevertheless, 2 important questions remain: ‘‘Are these the right pieces?’’ ‘‘Does the picture on the puzzle we are putting together really make sense?’’ Nearly a decade ago, Bob Robel (1993) challenged quail managers and researchers to consider 6 topics, with an assortment of associated questions (Table 1) that he considered were missing from the Quail III program. Since 10 years and 2 National Quail Symposia have now passed, I thought it would be productive to revisit Robel’s remarks, and use them as a basis to organize these closing comments. Most of Robel’s comments and questions emphasized key points of a national strategic planning workshop, which was conducted at Quail III (Brennan 1993), and revisited at Quail IV (Brennan and Carroll 2000). This Quail V wrap-up, for better or worse, provides an opportunity to elaborate on some points made in my ‘‘Progress and Frustration’’ paper, in the context of all North American quails, not just bobwhites (Colinus virginianus). This leads me to my first point, which is to lament the apparent lack of research on and interest in the western species of quail, as shown by these proceedings.

Montezuma Quail Management in Arizona

The Montezuma quail (Cyrtonyx montezumae meamsi) has substantially different habitat requirements than other quails found in the U.S. They inhabit evergreen oak woodlands of mountain ranges in the Southwest and feed primarily on underground bulbs and tubers. Populations respond to summer precipitation because the vegetation which provides food and cover for Montezuma quail flourishes after the summer rains. Moderate to heavy grazing increases availability of Montezuma quail food plants, but resultant lack of cover precludes use of such sites. Montezuma quail avoid areas with greater than 50% forage utilization by ungulates. As with other Arizona quail species, hunting has been shown to have limited or no impact on the population level during the following years. Birds may be depleted in localized areas temporarily, but available habitat is re-occupied when pre-nesting dispersal occurs. Annual pre- and posthunt flush counts were conducted 1988-1996 by the Arizona Game & Fish Department, United States Forest Service, volunteers, and local quail hunters. Average covey size decreased during the hunting season, but the magnitude of the decrease was similar in unhunted populations. Montezuma quail populations fluctuate in response to habitat and weather conditions. A state-wide hunter questionnaire program estimated total harvest trends for Arizona. In addition, wing collection barrels had been placed in heavily hunted areas from 1981 to 1996 to obtain hunter-effort information and sex/age characteristics of the harvest. Data from these wings indicate average percentage of juveniles in the harvest was higher for Montezuma quail (x = 74.4%, range = 55.9-84.9%) than other Arizona quail species, such as Gambel's (x = 65.6%, range = 23-77%). Hunters harvested an average of 2.2 Montezuma quail per day. In 3,107 hunter-days during this period, only 13 (0.4%) resulted in a limit of birds. Three of these limits occurred in 1996 when the bag limit was reduced from 15 to 8 Montezuma quail.

Delineation of Gambel's Quail Habitat in the Trans-Pecos, Texas

Gambel’s quail (Callipepla gambelii) are a common quail species in southwestern states of the United States and the northwestern states of Mexico. In Texas this species occurs in the Trans-Pecos region, are underutilized, and could become an important game bird and source of income for ranchers in the Chihuahuan Desert region of Texas. Salt cedar (Tamarisk spp.), introduced from Asia for ornamental and erosion purposes, is invasive in the western part of the Rio Grande corridor that generally creates monocultures that choke out the native vegetation of the region. Knowing this, the objectives of this study were to: (1) delineate salt cedar and native riparian habitats along the Rio Grande corridor in the Trans-Pecos; (2) evaluate those habitats based on the known distribution of Gambel’s quail in the Trans-Pecos; and (3) estimate the amount of suitable habitat for Gambel’s quail in Trans-Pecos, Texas. Although dominant along the Rio Grande, native riparian vegetation was more prevalent than salt cedar communities when combining primary creeks in all counties. Brewster County was the area with a higher percentage of salt cedar occurrence (21.2%) vs. native riparian vegetation (78.8%). The largest extension of salt cedar occurred in Presidio County with an extension of 6,656.3 ha but this only represented 12.7% of our analyzed area. Hudspeth County had an occurrence of salt cedar of 2,905.2 ha representing 6.8% of the estimated riparian area of the Rio Grande corridor in this county. El Paso County’s total urban area-agricultural fields area is a total of 90,682.9184 ha.

Management Implications of Estimating Abundance of Quail Inhabiting Forest Environs in Mexico

Estimating abundance of forest quail in Mexico offers unique challenges to wildlife managers. Unlike quail inhabiting grassland, forest quail are often cryptic, live in inaccessible mountainous areas, and unpredictably respond to playback census techniques. During 1996–1999, we estimated abundance of singing quail (Dactylortyx thoracicus) and bearded wood quail (Dendrortyx barbatus) in northeast Mexico. Singing quail were visually counted at El Cielo Biosphere Reserve, Tamaulipas, along 14 transects varying in length from 1,400 to 5,000 m. Because of the cryptic nature of bearded wood quail, visual counts proved unsuccessful in estimating abundance. Therefore, a tape recording of their chorus call was used to determine presence. Vocalizing wood quail were documented at 10 stations on a single 1,000 m transect near Coatepec, Veracruz. Because of the varied habitat types in the area total population estimates were not estimated. Only the numbers present along our transect are reported. Estimates of abundance of singing quail were obtained due to the homogenous habitat. Density estimates from Ejido Lazaro Cardenas for singing quail were 56 quail/45.4 ha (1 quail/0.8 ha). Density estimates for La Cueva were 30 quail/15.9 ha (1 quail/0.53 ha). The management of these quail species presents a substantial challenge for biologists, because of the difficulty in obtaining population estimates. The number of wood quail estimated by each responding individual to the chorus call and possible seasonal elevation shifts of singing quail should be considered when estimates of abundance are used to set harvest regulations.

Impact of Inclement Weather on Overwinter Mortality of Montezuma Quail in Southeast Arizona

Inclement weather such as droughts or hard freezes are known to negatively impact quail species and population viability models exist which have evaluated northern bobwhite (Colinus virginianus) response to summer and winter catastrophes. Previous research suggests inclement weather may be an important factor that contributes to mortality of Montezuma quail (Cyrtonyx montezumae), but few data have been collected to evaluate actual rates of overwinter mortality. We evaluated the overwinter mortality of Montezuma quail in southeast Arizona following an episode of severe winter weather consisting of 27.54 cm of precipitation, which occurred from January to March 2010. Overwinter mortality for radio-marked birds (n 1⁄4 23) was 95.6%. Total abundance using flush counts at a control site estimated an 88% reduction in the population following the episode of above-average precipitation. Post-hunting season flush counts across multiple study sites throughout the Coronado National Forest also support this trend. The 3-year (2007–2009) average (6 SD) (41.67 6 4.73) of birds flushed was ~ 80% higher than number of birds (n 1⁄4 8) flushed in the 2010 post-hunting season.

The Impact of Invasive Exotic Grasses on Quail in the Southwestern United States

Five native quail species inhabit arid and semi-arid ecosystems in the southwestern United States. One species is endangered, one species is declining throughout it’s historic range, another species is declining in portions of its historic range, and the other two species may be beginning to decline in selected portions of their respective ranges. A number of factors have been implicated for these declines, though habitat loss is frequently cited as the most common factor associated with southwestern quail declines. Exotic species invasions in the United States represent a significant economic and biological threat to the United States. Many exotic organisms introduced to the United States are threatening entire ecosystems, replacing native species and even threatening other native species with extinction. Numerous exotic grasses are invading arid and semi-arid ecosystems in the Southwest. Most exotic grasses were intentionally introduced for erosion control and to provide forage for livestock. Cattlemen sometimes favor exotic grasses in spite of their impacts to native biodiversty. The impacts of exotic grasses on vegetative communities are discussed, as well as their potential impacts on the five native quail species that inhabit the southwestern United States. Exotic grass eradication and control are also discussed, as well as introducing exotic grass pest management into existing land management programs. Research designed to determine the impacts of exotic grass invasions on quail and their habitat is recommended.

Population Trends and a Revised Management Plan for Quail in California

California supports a diversity of habitats suitable for mountain quail (Oreortyx pictus), California quail (Callipepla californica), and Gambel’s quail (Callipepla gambelii). These three species require different habitats for foraging, nesting and brood-rearing, and overwinter survival, yet most published information focuses on California quail. Currently the state-wide surveys for quail are limited to the North American Breeding Bird Survey (BBS) and the Audubon Christmas Bird Count. We used BBS data (1970–2013) to create abundance maps for quail throughout California. We developed 5-year averages to account for boom-and-bust cycles, and then established 100 random points for mountain and California quail, and 60 random points for Gambel’s quail. Mountain quail populations have declined from high counts in the late 1970s. California quail populations peaked in the early 1990s, declined in the early 2000s, rebounded and are currently declining again. Gambel’s quail populations peaked in the mid-1990s and in 2004, but have been declining since. Currently we are comparing quail population trends to road density, human population, and land use on a broad-scale. Improving our understanding of California’s quail species requires research and monitoring across multiple spatial scales at which their population dynamics are influenced. At the large-scale (statewide), we are developing fall quail surveys to monitor population trends. Additionally, we are continuing fine-scale (local) counts at water sources and other locations. There is a poor understanding of western quail biology relative to northern bobwhite, therefore our new management plan will focus on prioritized research needs, including the relationship of quail to habitat, home range estimation, methods for population estimation that include detection probabilities, and genetic diversity and population structure.

Impacts of Invasive, Exotic Grasses on Quail of Southwestern Rangelands: A Decade of Progress?

Exotic grass invasions are a serious concern for State and Federal agencies, non-government organizations, and private landowners engaged in quail conservation and management. Quail biologists recognized the potential negative impacts of exotic grass invasion on North American quail populations 2 decades ago. This issue was addressed in a review paper published in the Proceedings of the 5th National Quail Symposium in 2002. That paper reported the state of our knowledge on impacts of exotic grass invasions on 5 quail species inhabiting southwestern rangelands. Our objective is to update the progress of exotic grass-quail research on southwestern rangelands during the past decade by reviewing studies that provide specific results about the impacts of exotic grass invasions on southwestern quail populations. Results of studies that have quantified the impacts of exotic grass on quail habitat use are summarized and discussed along with studies that describe how exotic grasses impact important components of quail habitat such as diversity and abundance native herbaceous plants and arthropods. Management of exotic grasses is also discussed.

Fate and Survival of Radio-marked Montezuma Quail

Montezuma quail (Cyrtonyx montezumae) represent one of the least studied North American quail species, particularly in Texas. This lack of information may be partly due to their secretive nature and difficulty of capturing. We provide the first published report of fate of radio-marked Montezuma quail in Texas. We captured, radio-marked, and released 14 Montezuma quail on Elephant Mountain (n = 9) and Davis Mountain Preserve (n = 5) during 2000-2005. We used 2 methods of attachment for pendant style neck-loop radio transmitters. Body-loop transmitters were affixed to quail captured at the Davis Mountain Preserve whereas both body-loop and neck-loop were used at Elephant Mountain. All radio-marked Montezuma quail died within a relatively short period (1-16 days). Causes of mortality for most Montezuma quail were attributed to raptors (n = 9), mammals (n = 1), and miscellaneous (n = 4). Because this low survival rate would not sustain a natural population, we suspect trapping, handling, and/or radio-marking negatively affected survival. It is possible that transmitters potentially restricted escape movements or interfered with other behavior thereby making Montezuma quail more vulnerable to predation. Traditional techniques used to affix radio transmitters or transmitter design itself need to be refined if Montezuma quail are to be studied using radio telemetry.

Evaluating the Efficacy of Brood Flush Counts: A Case Study in Two Quail Species

Abstract. Taking brood flush counts is a common sampling method that has been used for decades to estimate brood and chick survival in many gallinaceous bird species. However, brood survival estimates based upon flush counts may be biased because of low detection probabilities, occurrence of brood amalgamations, brood abandonment, and brooding adult mortality. Given that brood flush counts are still commonly used to estimate brood survival, and in some cases extrapolated to provide an estimate of chick survival, it is important to evaluate biases associated with this method. Therefore, we evaluated the use of brood flush counts to estimate brood survival of 2 gallinaceous birds: Northern Bobwhite (Colinus virginianus) and Scaled Quail (Callipepla squamata). To gain a better understanding of some of the mechanisms that may bias brood survival estimates, we radio-tagged Northern Bobwhite and Scaled Quail chicks (8–12 days old) and juveniles (4–6 weeks old) in 67 broods. We used radio-tagged chicks and juven...

Extreme climatic events constrain space use and survival of a ground-nesting bird.

Two fundamental issues in ecology are understanding what influences the distribution and abundance of organisms through space and time. While it is well established that broad-scale patterns of abiotic and biotic conditions affect organisms' distributions and population fluctuations, discrete events may be important drivers of space use, survival, and persistence. These discrete extreme climatic events can constrain populations and space use at fine scales beyond that which is typically measured in ecological studies. Recently, a growing body of literature has identified thermal stress as a potential mechanism in determining space use and survival. We sought to determine how ambient temperature at fine temporal scales affected survival and space use for a ground-nesting quail species (Colinus virginianus; northern bobwhite). We modeled space use across an ambient temperature gradient (ranging from -20 to 38°C) through a maxent algorithm. We also used Andersen-Gill proportional hazard models to assess the influence of ambient temperature-related variables on survival through time. Estimated available useable space ranged from 18.6% to 57.1% of the landscape depending on ambient temperature. The lowest and highest ambient temperature categories (<-15°C and >35°C, respectively) were associated with the least amount of estimated useable space (18.6% and 24.6%, respectively). Range overlap analysis indicated dissimilarity in areas where Colinus virginianus were restricted during times of thermal extremes (range overlap=0.38). This suggests that habitat under a given condition is not necessarily a habitat under alternative conditions. Further, we found survival was most influenced by weekly minimum ambient temperatures. Our results demonstrate that ecological constraints can occur along a thermal gradient and that understanding the effects of these discrete events and how they change over time may be more important to conservation of organisms than are average and broad-scale conditions as typically measured in ecological studies.

Infection levels of the eyeworm Oxyspirura petrowi and caecal worm Aulonocephalus pennula in the northern bobwhite and scaled quail from the Rolling Plains of Texas.

Northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) have experienced chronic declines within the Rolling Plains ecoregion of Texas. Parasitic infection, which has long been dismissed as a problem in quail, has not been studied thoroughly until recently. A total of 219 northern bobwhite and 101 scaled quail from Mitchell County, Texas were captured and donated from 2014 to 2015, and examined for eyeworm (Oxyspirura petrowi) and caecal worm (Aulonocephalus pennula) infections. In 2014, bobwhites averaged 19.6 ± 1.8 eyeworms and 98.6 ± 8.2 caecal worms, and 23.5 ± 2.1 eyeworms and 129.9 ± 10.7 caecal worms in 2015. Scaled quail averaged 4.8 ± 1.0 eyeworms and 50 ± 6.8 caecal worms in 2014, and 5.7 ± 1.3 eyeworms and 38.1 ± 7.1 caecal worms in 2015. This study expands the knowledge of parasitic infection in quail inhabiting the Rolling Plains of Texas. A significant difference was documented in O. petrowi infection between species but there was no significant difference in A. pennula between quail species. No significant difference was detected in parasite infection between the sexes of both northern bobwhite and scaled quail. This study also documented the highest reported O. petrowi infection in both species of quail. Additional research is needed on the life history and infection dynamics of O. petrowi and A. pennula infections to determine if there are individual- and/or population-level implications due to parasitic infection.