Demographic and Density Response of Northern Bobwhites to Pyric Herbivory of Non-Native Grasslands

Usable space for northern bobwhites (Colinus virginianus) has declined significantly over the past 3 decades in Texas because non-native grasses have replaced native vegetation. We hypothesized that burning patches in pastures dominated by buffelgrass (Pennisetum ciliare) and Old World bluestems (Bothriochloa spp. and Dichanthium spp.) followed by livestock grazing would increase limiting habitat attributes, thereby increasing usable space and bobwhite demographic parameters and population densities. Our study was conducted during 2009–2011 in LaSalle County, Texas on a ranch dominated by non-native grasses. Our experimental design was composed of 2 blocks with two 240-ha pastures, one control (graze only), and one treatment (patch-burn and graze) in each. We estimated grass standing crop in grazing exclosures (June–September) and habitat attributes along transects (October) 2009–2011. Bobwhites were captured and monitored via radiotelemetry 2–3 times/wk during March–November. Means of vegetation metrics important to bobwhites such as bare ground, traversibility, and forb and subshrub cover were similar between control and treatment units in post-treatment years. However, grass standing crop tended to be lower in treatment (June and August 2010 and September 2011—110.5 ± 26.2 g/m²) compared with control units (June and August 2010 and September 2011—145.5 ± 58.6 g/m²). Plant species richness was also greater (21%) in treatment (4.6 ± 0.4/0.1 m²) compared with control units (3.8 ± 0.4/0.1 m²) during the last year of the study (P ≥ 0.057). Patch heterogeneity was increased in treatment units. There was an increase in bobwhite densities in treatment units, although demographic metrics remained similar between treatment and controls. Patch burning and grazing is a viable tool for managing monotypic non-native grasslands for bobwhites in semiarid environments.     

Breeding Bird Use of Production Stands of Native Grasses—a Working Lands Conservation Approach

Grassland birds have experienced protracted population declines, primarily due to loss and degradation of native grasslands. Restoration of native grasses may benefit grassland birds, but such restoration within the eastern United States has been limited. Production uses of native grasses (e.g., hay, pasture, biofuel feedstock) provide market-based incentives that could lead to more extensive use of these grasses than existing conservation-focused practices, potentially influencing breeding birds. Therefore, we compared breeding bird (n = 9 target species) relative abundance among 4 types of native warm-season grass (NWSG) agricultural production fields: forage (hay and pasture; n = 22 and 7, respectively), seed (n = 21), biofuel (n = 15), and a control (idle fields in conservation programs or practices; n = 37) in Kentucky and Tennessee, 2009–2010. We detected 2 145 birds, with field sparrow (Spizella pusilla, 43%) and red-winged blackbird (Agelaius phoeniceus, 27%) encountered most often. Relative abundance did not differ between production types and controls except for field sparrow (lower on seed production fields) and northern bobwhite (Colinus virginianus, lower on hay production fields). Species richness equaled or exceeded that of control fields for all production categories. We documented negative relationships between relative abundance and landscape-scale forest cover for four species (field sparrow, grasshopper sparrow [Ammodramus savannarum], eastern meadowlark [Sturnella magna], and red-winged blackbird) and positive relationships with amount of pasture and hay cover for four species (northern bobwhite, grasshopper sparrow, eastern meadowlark, and red-winged blackbird), reinforcing the importance of nonforested environments for these species. We conclude that production stands could be a viable approach for increasing NWSG available for breeding birds and, when established in the appropriate landscape context, can provide benefits similar to those provided by conservation programs.     

Common Broomweed Growth Characteristics in Cleared and Woody Landscapes

Common broomweed (Amphiachyris dracunculoides [DC] Nutt. Ex Rydb.) is an annual forb that occurs throughout the southern Great Plains, USA. During years of abundant growth, broomweed is problematic because it can reduce grass production and interfere with livestock foraging. In contrast, the canopy structure of broomweed may provide habitat cover for wildlife, including the northern bobwhite quail (Colinus virginianus Linnaeus). During an extreme outbreak of broomweed in north Texas in 2007, we observed apparent differences in broomweed individual plant growth characteristics in mesquite (Prosopis glandulosa Torr.) woodland areas versus areas that had recently been cleared of mesquite. Our objective was to document differences at the individual plant and population levels. Individual plant mass, canopy diameter, and basal stem diameter were much greater in the cleared treatment than the mesquite woodland. In contrast, plant height was greater in the woodland than in the cleared treatment. Population variables of stand-level production, percentage canopy cover, plant density, and visual obstruction were not different between treatments. Total perennial grass production was greater in the cleared than the woodland treatment, because of the negative effect of mesquite on grass production. Variations in broomweed growth characteristics may have implications regarding livestock foraging and wildlife habitat.     

Health status of northern bobwhite quail (Colinus virginianus) in eastern Kansas

The health status of wild northern bobwhite quail (Colinus virginianus) from Lyon County, Kansas, was evaluated by conducting comprehensive health assessments on 25 birds. Gross lesions indicative of avian pox, ulcerative enteritis, and quail bronchitis were not present. Serologic tests for antibodies to Salmonella pullorum, Salmonella gallinarum, Pasteurella multocida, Mycoplasma gallisepticum, Mycoplasma synoviae, and avian adenoviruses were all negative. Intestinal coccidia (Eimeria spp.) were found in 36% of the birds. Only three species of helminth parasites were found: Dispharynx nasuta in two birds, Cyrnea colini in one bird, and larval Physaloptera sp. in four birds. Arthropod parasites (ticks, lice, mites, and/or chiggers) were present on 96% of the birds examined. Compared with wild bobwhite populations in the southeastern United States, the diversity, prevalence, and intensities of microbial and parasitic agents were low.     

Chukar Watering Patterns and Water Site Selection

We evaluated chukar (Alectoris chukar) watering patterns as well as habitat variables influencing water site selection in western Utah. Motion-sensing cameras and chukar dropping counts were primary techniques to evaluate watering patterns. We took vegetative and other habitat measurements at each water source (n = 43) to discriminate use from nonuse sites using logistic regression. Chukars watered during daylight hours with a modal hour from 1200 hours to 1300 hours daylight savings time. Annual patterns suggest limited use of water sources from November to May with first observed visits occurring in June and last observed visits in October. Shrub canopy cover was the only variable to discriminate between site types (P &spilt; 0.01). Cross validation showed a predictive success rate of 84%. Significant differences were found between use and nonuse sites in terms of security cover (P &spilt; 0.01), but not total cover (P &spigt; 0.05). Chukars seem to have a loose shrub canopy threshold near 11% that is likely due to predation risk. Water sources meeting this threshold received use, whereas those not meeting this threshold did not. Increasing shrub canopy cover above 11% did not translate into increased water source use. Managers might want to consider annual patterns when setting hunt season timing and structure as well as judging sites for new water developments based on shrub canopy cover. More generally, these results suggest a behavioral constraint on the use of water sources as a function of predation risk—we should expect other species to demonstrate similar behavioral constraints. These constraints must be considered in any effort to determine benefits or impacts of water developments.     

Density-Dependent Ecohydrological Effects of Piñon–Juniper Woody Canopy Cover on Soil Microclimate and Potential Soil Evaporation

Many rangeland processes are driven by microclimate and associated ecohydrological dynamics. Most rangelands occur in drylands where evapotranspiration normally dominates the water budget. In these water-limited environments plants can influence abiotic and biotic processes by modifying microclimate factors such as soil temperature and potential soil evaporation. Previous studies have assessed spatial variation in microclimate and associated ecohydrological attributes within an ecosystem (e.g., under vs. between woody canopies) or across ecosystems (e.g., with differing amounts of woody canopy cover), but generally lacking are assessments accounting systematically for both, particularly for evergreen woody plants. Building on recently quantified trends in near-ground solar radiation associated with a piñon–juniper gradient spanning 5% to 65% woody canopy cover, we evaluated trends in soil temperature and associated estimates of potential soil evaporation as a function of amount of woody canopy cover for sites overall and for associated canopy vs. intercanopy locations. Quantified soil temperature trends decreased linearly with increasing woody canopy cover for intercanopy as well as canopy patches, indicating the coalescing influence of individual canopies on their neighboring areas. Notably, intercanopy locations within high-density (65%) woody canopy cover could be as much as ～10°C cooler than intercanopy locations within low-density (5%) cover. Corresponding potential soil evaporation rates in intercanopies within high-density woody canopy cover was less than half that for intercanopies within low density. Our results highlight ecohydrological consequences of density-dependent shading by evergreen woody plants on soil temperature and potential soil evaporation and enable managers to rapidly estimate and compare approximate site microclimates after assessing amounts of woody canopy cover. Such predictions of microclimate have general utility for improving management of rangelands because they are a fundamental driver of many key processes, whether related to understory forage and herbaceous species or to wildlife habitat quality for game or nongame species.     

Grazing History Affects Willow Communities in a Montane Riparian Ecosystem

This study was conducted to compare data from 12 grazed and ungrazed areas and to examine the impacts of grazing treatments on a montane willow community during an 11-year period. Data were collected on willow canopy cover, species diversity, height, and stem density in a montane riparian ecosystem between 1988 and 1999 from 4 grazing treatments: long-term grazing (since the early 1900s), long-term grazing exclusion (exclosures built in the 1950s), recent grazing (sections of exclosures opened in 1988), and recent grazing exclusion (exclosures built in 1988). Willow canopy cover increased significantly for all treatments through time, with the recent grazing exclusion treatment becoming similar to that of the long-term exclusion treatment within 5 years. Species diversity was greatest in the long-term grazed treatment. Willow height averaged over treatments increased from 1988 to 1997 (P = 0.0001), but did not increase significantly after that. Height in the long-term exclosure averaged over time from 1988 to 1997 was 1.5 times greater than in the long-term grazing treatment. Stem density of willows was significantly greater in the recent exclosure than in the long-term exclosure (P = 0.008, 180%) and recent grazing treatments (P = 0.02, 120%). Recent grazing exclusion resulted in the greatest increase in canopy cover, height growth, and stem density during the 11 years of study, indicating that these variables respond positively to removal of livestock grazing. Results suggest that continued long-term grazing exclusion may lead to a closed canopy, lower willow species diversity, reduction in new stem height growth, and reduced stem recruitment. Information on the dynamics of willow growth under different grazing treatments should help resource managers determine appropriate livestock utilization levels in similar riparian areas, and develop management plans for these important ecosystems.     

Culicoides bottimeri as a vector of Haemoproteus lophortyx to quail in California, USA

Arthropod sampling via periodic direct bird examination and regular light trapping was conducted between June 2000 and October 2002 to survey for potential vectors of Haemoproteus lophortyx to nonnative, captive-raised bobwhite quail (Colinus virginianus) in northern California, USA. Examination of individual bobwhite quail (from 5 weeks of age through adult, total n=76) was conducted on several dates during the transmission period (June-October). No ectoparasites, including hippoboscid flies (reported as Haemoproteus vectors to wild quail in early literature), were collected from the birds. Trapping with ultraviolet light suction traps near the quail revealed nine species of biting midges (Culicoides spp.). Of these, 94% were C. bottimeri, which was abundant near the birds, and 65% of collected C. bottimeri were engorged with blood. C. bottimeri adult activity began in late-April, slightly before the onset of disease in the quail. Activity peaked between July and late-September, coincident with maximum reported transmission, and adult activity ceased by early-November. Nonengorged C. bottimeri had a parity rate of 43.6% overall, suggesting excellent survival for biological transmission of a pathogen like H. lophortyx. A controlled study was done injecting a macerated slurry of pooled, nonengorged, wild-caught C. bottimeri into the peritoneum of 1-day-old bobwhite quail hatchlings held in insect-proof containers. Blood smears 13-19 days later confirmed H. lophortyx infection in zero controls but all insect-injected quail. Biting midges, especially C. bottimeri, transmit H. lophortyx to captive quail and probably are the dominant vector to native California quail (Callipepla californica) as well.     

Postfire Recovery of Sagebrush Communities: Assessment Using Spot-5 and Very Large-Scale Aerial Imagery

Much interest lies in long-term recovery rates of sagebrush communities after fire in the western United States, as sagebrush communities comprise millions of hectares of rangelands and are an important wildlife habitat. Little is known about postfire changes in sagebrush canopy cover over time, especially at a landscape scale. We studied postfire recovery of shrub canopy cover in sagebrush-steppe communities with the use of spectral mixture analysis. Our study included 16 different fires that burned between 1937 and 2005 and one unburned site at the US Sheep Experiment Station in eastern Idaho. Spectral mixture analysis was used with September 2006 Systeme Pour l’Observation de la Terre-5 (SPOT-5) satellite imagery to estimate percent shrub canopy cover within pixels. Very large-scale aerial (VLSA) imagery with 24-mm resolution was used for training and validation. SPOT-5 image classification was successful and the spectral mixture analysis estimates of percent shrub canopy cover were highly correlated with the shrub canopy cover estimates in the VLSA imagery (R² = 0.82; P < 0.0001). Additional accuracy assessment of shrub classification produced 85% overall accuracy, 98% user’s accuracy, and 78% producer’s accuracy. This successful application of spectral mixture analysis has important implications for the monitoring and assessment of sagebrush-steppe communities. With the use of the percent shrub canopy cover estimates from the classified SPOT-5 imagery, we examined shrub canopy recovery rates since different burn years. With the use of linear-plateau regression, it was determined that shrub cover in mountain big sagebrush (Artemisia tridentata Nutt. subsp. vaseyana [Rydb.] Beetle) communities recovered approximately 27 yr after fire, with an average shrub cover of 38%. These results are consistent with other field-based studies in mountain big sagebrush communities.     

Mapping Mesquite (Prosopis) Distribution and Density Using Visual Aerial Surveys

Mapping the distribution and abundance of invasive plants is a high priority, but establishing cost-effective and practical techniques at appropriate scales remains elusive. Mesquite is a highly invasive shrub that cannot currently be reliably distinguished from other plant species using remote sensing technologies, at least not at accuracies necessary for mapping mesquite at very low densities. This paper describes and tests an alternative method. A visual, aerial technique was used to map a large mesquite (Leguminoseae: Prosopis spp.) population in Australia; 216 654 ha was surveyed in 18.5-ha grid cells to include the entire population. The objective was to test the ability of this technique to detect and map mesquite at very low densities for surveillance and to assist in prioritizing management effort and, where mesquite was well established, to categorize mesquite into broad canopy cover classes for change detection and to identify habitat associations. The survey technique was very effective at detecting isolated mesquite plants (&spilt; 0.6% canopy cover across a grid cell), which is considerably better than existing remote sensing technologies. Detection of low-density mesquite was particularly important, as most occupied grid cells (55%) had isolated mesquite, and their management may offer the best return on investment. The technique was also competitive cost wise ($0.39 USD per hectare) and required relatively little expertise. Grid cells with moderate (20%–50%) to dense (&spigt; 50%) canopy covers were almost all restricted to a 32 500-ha area on the floodplain delta of the Fortescue River, where the original introductions occurred. Cover class estimates appeared to be well calibrated between observers within a survey; however, they were poorly calibrated between independently conducted surveys, suggesting that further methodological refinement is necessary if this technique is to be reliable for change detection.     

A survey for Toxoplasma gondii antibodies in deer and other wildlife on a sheep range.

Blood samples were obtained from native mammals and birds on a sheep range (Hopland Field Station) in northern California. Serums were tested for antibodies to Toxoplasma gondii by the indirect hemagglutination test. Of 382 deer that were tested from 1964 to 1973, 77 (20%) were seropositive for T gondii. Among 36 serums representing 6 species of wild carnivores (badgers, bobcats, coyotes, foxes, raccoons, and skunks), 18 (50%) were seropositive. All of the 5 bobcats tested were seropositive, with antibody titers ranging from 1:65,536. The testing of 175 serums from small wild mammals indicated antibody prevalence of 8% among jackrabbits, 6% among brush rabbits, and 2% among squirrels. None of the native mice tested was seropositive for T gondii. Of 120 native birds tested, 6 (5%) were seropositive. Of the resident domestic species of animals tested, antibodies were found in 1 of 7 domestic cats, 1 of 5 feral cats, 1 of 2 dogs, and 54 (13%) of 405 sheep.     

Mapping Tree Canopy Cover in Support of Proactive Prairie Grouse Conservation in Western North America

Invasive woody plant expansion is a primary threat driving fragmentation and loss of sagebrush (Artemisia spp.) and prairie habitats across the central and western United States. Expansion of native woody plants, including conifer (primarily Juniperus spp.) and mesquite (Prosopis spp.), over the past century is primarily attributable to wildfire suppression, historic periods of intensive livestock grazing, and changes in climate. To guide successful conservation programs aimed at reducing top-down stressors, we mapped invasive woody plants at regional scales to evaluate landscape level impacts, target restoration actions, and monitor restoration outcomes. Our overarching goal was to produce seamless regional products across sociopolitical boundaries with resolution fine enough to depict the spatial extent and degree of woody plant invasion relevant to greater sage-grouse (Centrocercus urophasianus) and lesser prairie-chicken (Tympanuchus pallidicinctus) conservation efforts. We mapped tree canopy cover at 1-m spatial resolution across an 11-state region (508 265 km²). Greater than 90% of occupied lesser prairie-chicken habitat was largely treeless for conifers (< 1% canopy cover), whereas > 67% was treeless for mesquite. Conifers in the higher canopy cover classes (16 ? 50% and > 50% canopy cover) were scarce (< 2% and 1% canopy cover), as was mesquite (< 5% and 1% canopy cover). Occupied habitat by sage-grouse was more variable but also had a relatively large proportion of treeless areas ($\stackrel{?}{x}$ = 71, SE = 5%). Low to moderate levels of conifer cover (1 ? 20%) were fewer ($\stackrel{?}{x}$ = 23, SE = 5%) as were areas in the highest cover class (> 50%; $\stackrel{?}{x}$ = 6, SE = 2%). Mapping indicated that a high proportion of invading woody plants are at a low to intermediate level. Canopy cover maps for conifer and mesquite resulting from this study provide the first and most geographically complete, high-resolution assessment of woody plant cover as a top-down threat to western sage-steppe and prairie ecosystems.     

印度西高止山脉全球濒危物种灰头林鸽的觅食生态学

在印度西高止山脉(Western Ghats),通过粪便取样和直接观察两种方法,对全球濒危物种灰头林鸽(Columba elphinstonii)的觅食生态进行了研究.结果表明,灰头林鸽取食39种植物的果实、11种植物的种子、4种植物的花和叶芽,以及少量地面无脊椎动物.不同季节的直接观察结果显示,有9种植物的被取食频率较高(占观察总次数的47%),其中取食樟科植物果实的频次最高.灰头林鸽主要在树冠中上部(高于6米)外围的树枝上取食,全年中拾取行为占取食方法的76%.取食果实的频率与果实丰富度显著相关,而后者由降雨量决定.本研究表明,林鸽在不同森林资源条件下需要一个多样化的食物谱.保护这一物种需要保留其全年所需资源的所有栖息地类型.     

Precision,Repeatability, and Efficiency of Two Canopy-Cover Estimate Methods in Northern Great Plains Vegetation

Government agencies are subject to increasing public scrutiny of land management practices. Consequently, rigorous, yet efficient, monitoring protocols are needed to provide defensible quantitative data on the status and trends of rangeland vegetation. Rigor requires precise, repeatable measures, whereas efficiency requires the greatest possible information content for the amount of resources spent acquiring the information. We compared two methods—point frequency and visual estimate—of measuring canopy cover of individual plant species and groups of species (forbs vs. graminoids, native vs. nonnative) and plant species richness. These methods were compared in a variety of grassland vegetation types of the northern Great Plains for their precision, repeatability, and efficiency. Absolute precision of estimates was similar, but values generally differed between the two sampling methods. The point-frequency method yielded significantly higher values than the visual-estimate method for cover by individual species, graminoid cover, and total cover, and yielded significantly lower values for broadleaf (forb + shrub) cover and species richness. Differences in values derived by different sampling teams using the same method were similar between methods and within precision levels for many variables. Species richness and median species cover were the major exceptions; for these, the point-frequency method was far less repeatable. As performed in this study, the visual-estimate method required approximately twice the time as did the point-frequency method, but the former captured 55% more species. Overall, the visual-estimate method of measuring plant cover was more consistent among observers than anticipated, because of strong training, and captured considerably more species. However, its greater sampling time could reduce the number of samples and, therefore, reduce the statistical power of a sampling design if time is a limiting factor.     

Northern Bobwhite (Colinus virginianus) Space Use Minimally Affected by Oil and Gas Development

Despite the fact that the northern bobwhite (Colinus virginianus Linnaeus; hereafter, bobwhite) is one of the most well-studied and widely distributed wildlife species in North America, we know little about how bobwhite respond to oil and gas infrastructure. We investigated the impacts of oil and gas development on space use of bobwhite using a multiseason approach. We captured and monitored bobwhite in the breeding season (1 April–30 September, n = 135 individuals) and nonbreeding season (1 October–31 March, n = 30 coveys) and modeled their habitat selection in a resource-utilization function (third order, within home range selection) and resource-selection function (second order, home range selection) format. Generally, energy infrastructure effects on bobwhite were neutral, but breeding season bobwhite did select for areas near low-traffic roads (β = ? 0.31 ± 0.15 SE). In the nonbreeding season, coveys selected for areas within their home range with a limited viewshed (i.e., areas with limited visibility of anthropogenic structures; β = ? 0.03 ± 0.02 SE). Selection differed between sexes for well pads (t = ? 2.12, P = 0.04) but was otherwise similar. At the level of home range selection, bobwhite exhibited a preference for areas with a low density of oil and gas wells and a high density of low-traffic roads during both the breeding and nonbreeding seasons (breeding: β_well = ? 0.14 ± 0.02, β_road = 0.26 ± 0.27; nonbreeding: β_well = ? 0.08 ± 0.03, β_road = 0.16 ± 0.03). As a generalist species, bobwhite appear to be largely tolerant of energy infrastructure and associated disturbances at moderate levels of development but may be sensitive to high densities of oil and gas pads.     

Plant Community Response Following Removal of Juniperus virginiana from Tallgrass Prairie: Testing for Restoration Limitations

Woody plant encroachment in natural grasslands is a widely documented global phenomenon that alters ecosystem dynamics by altering historic vegetation composition and suppressing herbaceous productivity. Abundant woody plants often suppress native plants sufficiently to establish successional thresholds difficult to reverse without species augmentation. Juniper (Juniperus virginiana L.) is expanding in North American tallgrass prairie, but it is currently unknown if encroachment creates successional restrictions that limit restoration potential. We selected 16 50×50-m sites with juniper canopy cover ranging from zero to approximately 75% in tallgrass prairie near Stillwater, Oklahoma, USA. Juniper trees were removed from 7 of the sites along the gradient of juniper canopy cover. Canopy cover of plant species and herbaceous plant productivity were estimated at each site 1 year before and 1, 2, and 5 years after tree removal. Before trees were removed, plant species richness and productivity declined as juniper canopy cover increased, and plant community composition dissimilarity of reference sites increased as juniper canopy cover increased. These relationships remained consistent on all non-removal sites throughout the study. The first year after juniper removal, species richness increased on all removal sites compared to intact sites and productivity on removal sites increased two years after removal. Plant community dissimilarity between reference sites and juniper removal sites remained relatively high (30–60%) the first two years after tree removal on all removal sites, but dissimilarity was about 22% 5 years after juniper removal. Within 5 years, removal sites were comparable to reference plant communities. Grassland restoration frequently requires species manipulation and additional seeding, particularly when overcoming successional limitations. Juniper encroachment into tallgrass prairie alters plant community species composition and productivity. However, in our study, juniper associated succession limitations were not apparent, and complete autogenic restoration was achieved within 5 years without seeding or species manipulation.     

Is Altering Grazing Selectivity of Invasive Forage Species With Patch Burning More Effective Than Herbicide Treatments?

Invasion of rangeland by exotic forage species threatens ecosystem structure and function and can cause catastrophic economic losses. Herbicide treatments often are the focus of management efforts to control invasions. Management with the fire-grazing interaction (or patch burning) might suppress an invasive forage species that has grazing persistence mechanisms developed apart from the fire-grazing interaction. We studied tallgrass prairies invaded by sericea lespedeza (Lespedeza cuneata [Dum.-Cours.] G. Don) to compare rate of invasion between traditional management and management with patch burning, to evaluate the effect of burn season on sericea lespedeza invasion within pastures managed with patch burning, and to correlate canopy cover of sericea lespedeza to canopy cover of other functional groups with and without herbicides. Sericea lespedeza canopy cover increased from 1999 to 2005 in both traditional- and patch-burn pastures, but sericea lespedeza increased from 5% to 16% canopy cover in traditionally managed pastures compared to 3% to 5% in the patch-burn pastures. Rate of increase in canopy cover of sericea lespedeza was less in patches burned in summer (0.41% · year^-1) than in patches burned in spring (0.58% · year^-1) within patch-burn pastures. Most plant functional groups, including forbs, were weak-negatively correlated with canopy cover of sericea lespedeza. Although herbicide application reduced mass of sericea lespedeza, other components of the vegetation changed little. Herbicide treatments temporarily reduced sericea lespedeza but did not predictably increase other plant functional groups. Patch burning reduced the rate of invasion by sericea lespedeza by maintaining young, palatable sericea plants in the burn patch, and could play a vital role in an integrated weed management strategy on rangelands.     

Chlamydiosis in pen-raised bobwhite quail (Colinus virginianus) and chukar partridge (Alectoris chukar) with high mortality

In a flock of 12,000 bobwhite quail (Colinus virginianus) and 7200 chukar partridge (Alectoris chukar), the owner had 100% morbidity and 40%-50% mortality in birds between the ages of 2 and 4 wk. Affected birds were stunted and anorexic and had yellow/green diarrhea. Two- and 4-wk-old birds submitted for necropsy all had slight nasal discharge. Histopathologic examination revealed mild (bobwhite) to severe (chukar) rhinitis. Immunohistochemistry was positive for Chlamydia psittaci in all birds. Chlamydia psittaci organisms were demonstrated histopathologically in hematoxylin and eosin and Gimenez-stained slides. Management sanitation and treatment with chlortetracycline stopped further excessive losses. The owners were also infected. Treatment by their local physician with tetracycline alleviated symptoms.     

Low-dose immunization of northern bobwhites (Colinus virginianus) with Eimeria lettyae provides protection against a high-dose challenge

To determine whether northern bobwhite quail (Colinus virginianus) could be immunized against Eimeria lettyae by a low-dose inoculation of oocysts, we inoculated 30 birds each with either 100 or 1000 oocysts at 2 days of age (given orally by pipette). Four weeks after immunization, the immunized birds and unimmunized controls were challenged with 1 x 10(6) E. lettyae oocysts. Eight days after challenge, birds were killed and weighed, and their intestines examined for gross lesions. Effectiveness of the immunization was measured by analyzing weight gain, intestinal lesions, severity of diarrhea, feed conversion ratio, and oocyst production. After challenge, birds immunized with 100 or 1000 oocysts gained an average of 33.3 g and 28.9 g, respectively, whereas unimmunized challenged birds gained an average of 11.5 g. Immunized quail produced approximately 99.7% fewer oocysts, had minimal gross intestinal and cecal lesions, had minimal diarrhea, and had a 50% lower feed conversion ratio compared to unimmunized challenged controls. These findings indicate that vaccination is a viable option for controlling coccidiosis in quail and that further research into vaccination is warranted.