Search

Changes in land use and land cover throughout the eastern half of North America have caused substantial declines in populations of birds that rely on grassland and shrubland vegetation types, including socially and economically important game birds such as the Northern Bobwhite (Colinus virginianus; hereafter bobwhites). As much attention is focused on habitat management and restoration for bobwhites, they may act as an umbrella species for other bird species with similar habitat requirements. We quantified the relationship of bobwhites to the overall bird community and evaluated the potential for bobwhites to act as an umbrella species for grassland and shrubland birds. We monitored bobwhite presence and bird community composition within 31 sample units on selected private lands in the south-central United States from 2009 to 2011. Bobwhites were strongly associated with other grassland and shrubland birds and were a significant positive predictor for 9 species. Seven of these, including Bell’s Vireo (Vireo bellii), Dicksissel (Spiza americana), and Grasshopper Sparrow (Ammodramus savannarum), are listed as species of conservation concern. Species richness and occupancy probability of grassland and shrubland birds were higher relative to the overall bird community in sample units occupied by bobwhites. Our results show that bobwhites can act as an umbrella species for grassland and shrubland birds, although the specific species in any given situation will depend on region and management objectives. These results suggest that efficiency in conservation funding can be increased by using public interest in popular game species to leverage resources to meet multiple conservation objectives.

In response to the decline of northern bobwhite (Colinus virginianus; hereafter, bobwhite) in eastern Oklahoma, USA, a cost-share incentive program for private landowners was initiated to restore early successional habitat. Our objectives were to determine whether the program had an effect on bobwhite occupancy in the restoration areas and evaluate how local- and landscape-level habitat characteristics affect occupancy in both restoration and control areas. We surveyed 14 sample units that received treatment between 2009 and 2011, and 17 sample units that were controls. We used single-season occupancy models, with year as a dummy variable, to test for an effect of restoration treatment and habitat variables on occupancy. We found no significant treatment effect. Model selection showed that occupancy was best explained by the combination of overstory canopy cover and habitat area at both the local and landscape scales. Moran's I revealed positive spatial autocorrelation in the 1,000–3,000-m distance band, indicating that the likelihood of bobwhite occupancy increased with proximity to other populations. We show that creating ≥20 ha of habitat within 1–3 km of existing bobwhite populations increases the chance of restoration being successful. © 2013 The Wildlife Society. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

We used multiple lines of evidence to assess habitat selection, dietary choice, and nutritional outcomes for a population of North American elk (Cervus elaphus), confined to a relatively small and isolated landscape of public and private land in south-central Great Plains, USA. The area of suitable elk habitat was a topographically diverse matrix of mature oak savannah, C4-dominated grasslands, and C3-dominated agricultural fields surrounded by unsuitable lowlands fragmented by anthropogenic activities. We hypothesized that such disparity in habitat availability and quality resulted in subpopulation differences in the overall elk population. We used 3 methods to evaluate this premise: radiotelemetry to determine home range and habitat use, microhistology of plant fragments in feces to determine dietary selection, and fecal nitrogen (N) and stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) to assess nutritional outcomes of habitat use and dietary choice. By comparing these 3 approaches, we wanted to determine if fecal indices alone could efficiently and accurately identify subpopulation structuring. Compositional analyses from radiotelemetry observations of 21 female elk identified 2 subpopulations that occupied relatively disjunct areas and showed differential preferences for forested and cultivated fields in summer but comparable preferences for cultivated fields in winter. A third unmarked subpopulation of elk was known to be largely confined to an adjacent wildlife refuge. Microhistological analyses of feces collected in all 3 areas highlighted distinct diets, outcomes of habitat occupation by the 3 subpopulations. Increased use of cultivated forages in winter was evident for 2 of the subpopulations, but the extent of use by elk was dependent on availability of cultivated forages in areas they occupied. The refuge subpopulation had no access to cultivated forage. Fecal N, fecal δ13C, and fecal δ15N supported the premise that the subpopulation with the greatest access to cultivated forages was on a higher nutritional plane than the other 2 subpopulations. Changes in fecal N, fecal δ13C, and fecal δ15N paralleled percentages of cultivated forages in the diets highlighting the utility of such fecal indices as supplemental to or surrogates for traditional methods of habitat use and dietary selection in free-ranging ungulates.

Procapra przewalskii (Buchner, 1891), commonly called Przewalski's gazelle, is polytypic with 1 of the 2 subspecies (P. p. diversicornis) likely extinct. The species now occurs only in the Qinghai Lake region in northeastern Qinghai Province, western China, and predominately inhabits semiarid grassland steppe, stable sand dunes, and the desert–shrub ecotone between them. Numbers and distribution of P. przewalskii have decreased severely from historic levels, and up to 10 small and disjunct populations are vulnerable because of agricultural usurpation of preferred habitat, competition with livestock, and illegal hunting. Total population is perhaps as high as 1,000–1,300 individuals. It is a Class I species and listed as “Critically Endangered” in China and considered “Endangered” by the International Union for Conservation of Nature and Natural Resources. It is arguably among the most endangered large mammals on earth.

Mountain Plover (Charadrius montanus) populations are inefficiently sampled by Breeding Bird Surveys. As a result, targeted sampling of select populations of this species (with an estimated global population of 11,000–14,000 birds) can be valuable. Our objectives were to determine the breeding distribution and estimate the size of the Mountain Plover population in Oklahoma. We conducted a randomized point count survey in an area where Mountain Plovers were previously known to breed and conducted additional surveys over a larger area to better delimit the distribution. We used a removal model to estimate detection probability for raw counts obtained from 1104 point counts in 2004 and 2005, and derived a state-level population estimate using the detection-adjusted counts. Mountain Plovers used flat, bare, cultivated fields for nesting, and their distribution was closely tied to the presence of clay loam soils. We estimated that at least 68–91 Mountain Plovers bred in Oklahoma in 2004–2005. The low breeding density we observed may be due to the location of our study area near the southeastern edge of the breeding range of these plovers, the low-quality habitat provided by cultivated landscapes, or a combination of factors. Because the number of birds is small, the status of the Oklahoma population is not likely to have a large effect on the global population. However, additional information is needed to help determine if cultivated landscapes represented population sources or sinks. RESUMEN Las poblaciones de chorlo (Charadrius montanus) son muestreadas ineficientemente durante los censos de aves reproductivas (BBS). Como resultado, el muestreo particular de poblaciones seleccionadas (con un estimado global de 11,000a 14,000 individuos) puede ser de gran valor. Nuestros objetivos fueron determinar la distribucion reproductiva y estimar el tamano de las poblaciones del chorlo en Oklahoma. Llevamos a cabo una serie de conteos de punto al azar, en un area en donde previamente no se conocia que el ave se reproducia, y se condujeron censos adicionales en un area mayor para delimitar la distribucion del ave. Utilizamos un modelo de remocion para estimar la probabilidad de deteccion para conteos crudos y deribar un estimado de la poblacion a nivel estatal, de un total de 1104 conteos de puntos llevados a cabo durante el 2004 y el 2005. Los chorlos utilizaron areas llanas de cultivo con suelo desnudo, para el anidamiento y su distribucion estuvo asociada a la presencia de suelo arcillosos. Estimamos que entre 68–91 individuos se reprodujeron en Oklahoma entre el 2004–2005. La baja densidad reproductiva pudiera ser un artefacto de la localizacion de nuestra area de estudio, la cual queda cerca del borde sureste de su distribucion reproductiva, la baja calidad del habitat (como resultado del uso de estas para cultivos) o de una combinacion de factores. Aunque el numero de individuos resulto bajo, el estatus del chorlo en Oklahoma, no debe tener un efecto significativo sobre la poblacion global del ave. Sin embargo, se necesita informacion adicional para determinar si las areas de cultivo representan una fuente de riesgo para la poblacion.

Three species of Buteo hawks nest sympatrically in the southern Great Plains of the United States. Dietary overlap among them is broad and we tested the hypothesis these species partition their breeding habitat spatially. We compared land cover and topography around 224 nests of the three species breeding in shortgrass prairie in 2004 and 2005. Red-tailed Hawks (Buteo jamaicensis) nested almost exclusively in riparian timber surrounded by prairie (95% prairie land cover around nests) and disproportionately used areas with greater topographic relief within prairie landscapes. Swainson's Hawks (B. swainsoni) commonly nested in low-relief areas dominated by small-grain production agriculture but generally used habitats in proportion to availability. Most nest sites of Ferruginous Hawks (B. regalis) were in prairie (78% prairie land cover around nests), but some were in areas that were at least partially agricultural. Ferruginous Hawks had at least two times more sand sagebrush (Artemisia filifolia) ...

Grazing management has focused largely on promoting vegetation homogeneity through uniform distribution of grazing to minimize area in a pasture that is either heavily disturbed or undisturbed. An alternative management model that couples grazing and fire (i.e., patch burning) to promote heterogeneity argues that grazing and fire interact through a series of positive and negative feedbacks to cause a shifting mosaic of vegetation composition and structure across the landscape. We compared patch burning with traditional homogeneity-based management in tallgrass prairie to determine the influence of the two treatments on the aboveground invertebrate community. Patch burning resulted in a temporal flush of invertebrate biomass in patches transitional between unburned and patches burned in the current year. Total invertebrate mass was about 50% greater in these transitional patches within patch-burned pastures as compared to pastures under traditional, homogeneity-based management. Moreover, the mosaic of patches in patch-burned pastures contained a wider range of invertebrate biomass and greater abundance of some invertebrate orders than did the traditionally managed pastures. Patch burning provides habitat that meets requirements for a broad range of invertebrate species, suggesting the potential for patch burning to benefit other native animal assemblages in the food chain.

Regional wildlife–habitat models are commonly developed but rarely tested with truly independent data. We tested a published habitat model for black bears (Ursus americanus) with new data collected in a different site in the same ecological region (i.e., Ouachita Mountains of Arkansas and Oklahoma, USA). We used a Mahalanobis distance model developed from relocations of black bears in Arkansas to produce a map layer of Mahalanobis distances on a study area in neighboring Oklahoma. We tested this modeled map layer with relocations of black bears on the Oklahoma area. The distributions of relocations of female black bears were consistent with model predictions. We conclude that this modeling approach can be used to predict regional suitability for a species of interest.

Many studies of roost selection by forest-dwelling bats have concentrated on microhabitat surrounding roosts without providing forest stand-level preferences of bats; thus, those studies have provided only part of the information needed by managers. We evaluated diurnal summer roost selection by the bat community at the forest-stand level in a diversely forested landscape in the Ouachita Mountains of central Arkansas. Over a 6-year period, we evaluated 428 roost locations for 162 individual bats of 6 species. Using Euclidean distance analysis and individual bat as the experimental unit, all 6 species were selective (P

In tallgrass prairie, disturbances such as grazing and fire can generate patchiness across the landscape, contributing to a shifting mosaic that presumably enhances biodiversity. Grassland birds evolved within the context of this shifting mosaic, with some species restricted to one or two patch types created under spatially and temporally distinct disturbance regimes. Thus, management-driven reductions in heterogeneity may be partly responsible for declines in numbers of grassland birds. We experimentally altered spatial heterogeneity of vegetation structure within a tallgrass prairie by varying the spatial and temporal extent of fire and by allowing grazing animals to move freely among burned and unburned patches (patch treatment). We contrasted this disturbance regime with traditional agricultural management of the region that promotes homogeneity (traditional treatment). We monitored grassland bird abundance during the breeding seasons of 2001-2003 to determine the influence of altered spatial heterogeneity on the grassland bird community. Focal disturbances of patch burning and grazing that shifted through the landscape over several years resulted in a more heterogeneous pattern of vegetation than uniform application of fire and grazing. Greater spatial heterogeneity in vegetation provided greater variability in the grassland bird community. Some bird species occurred in greatest abundance within focally disturbed patches, while others occurred in relatively undisturbed patches in our patch treatment. Henslow's Sparrow, a declining species, occurred only within the patch treatment. Upland Sandpiper and some other species were more abundant on recently disturbed patches within the same treatment. The patch burn treatment created the entire gradient of vegetation structure required to maintain a suite of grassland bird species that differ in habitat preferences. Our study demonstrated that increasing spatial and temporal heterogeneity of disturbance in grasslands increases variability in vegetation structure that results in greater variability at higher trophic levels. Thus, management that creates a shifting mosaic using spatially and temporally discrete disturbances in grasslands can be a useful tool in conservation. In the case of North American tallgrass prairie, discrete fires that capitalize on preferential grazing behavior of large ungulates promote a shifting mosaic of habitat types that maintain biodiversity and agricultural productivity.

Little is known about the ecology of the alligator snapping turtle, Macrochelys temminckii, particularly demography and behavior. To learn more about the species in Oklahoma, we conducted a telemetry project on 2 small streams at Sequoyah National Wildlife Refuge, an 8,417.5-ha refuge located in east-central Oklahoma. Between June 1999 and August 2000, we fitted 19 M. temminckii with ultrasonic telemetry tags and studied turtle movements and microhabitat use. Turtles were checked 2 to 3 times weekly in summer and sporadically in winter. Several microhabitat variables were measured at each turtle location and a random location to help quantify microhabitat use vs. availability. We recorded 147 turtle locations. Turtles were always associated with submerged cover with a high percentage of overhead canopy cover. Turtles used deeper depths in late summer (but not deeper depths than random locations) and deeper depths in midwinter (and deeper depths than random locations) than in early summer. They us...

Understanding how populations expand to recolonize former habitats is important to restoration efforts in wildlife management and conservation. Translocation of black bears (Ursus americanus) to Arkansas in the 1950s and 1960s has led to recolonization of former bear range in Oklahoma, with substantial increases in distribution and abundance of the species in Oklahoma over the last 15 years. We studied demographics of black bears in southeastern Oklahoma from May 2001 to November 2002 to provide insight into characteristics of recolonizing populations of large carnivores. We trapped 51 black bears (22 M, 29 F) 77 times and radiocollared 25 female bears. Sex ratios of adults and cubs were skewed toward females, and the age structure was younger than observed in other unharvested populations. Survival of adult females was estimated at 0.9 ±0.1, and fertility was estimated at 0.77 female young/female/year. Density on the study area was estimated at 0.21 bears/km2 and the current finite growth rate (...

Changes in landscape cover in the Great Plains are resulting from the range expansion and invasion of eastern red cedar (Juniperus virginiana). By altering the landscape and local vegetation, red cedar is changing the structure and function of habitat for small mammals. We examined effects of invasion by eastern red cedar on small mammals in 3 plant communities (tallgrass prairie, old field, and cross-timbers forest) in the cross-timbers ecoregion in Oklahoma. We sampled small mammals seasonally from May 2001 to August 2002 by using Sherman live traps and mark‐recapture techniques on 3.24-ha, 450-trap grids in each plant community. We sampled vegetation in two hundred twenty-five 12� 12-m cells within each grid. The structure of the smallmammal community differed among the 3 habitat types, with higher species diversity and richness in the tallgrass-prairie and old-field sites. Overall, the small-mammal community shifted along a gradient of increasing eastern red cedar. In the old-field and tallgrass-prairie plots, occurrence of grassland mammals decreased with increasing red cedar, whereas only 1 woodland mammal species increased. In the cross-timbers forest site, percent woody cover (,1 m in height), rather than cover of red cedar, was the most important factor affecting woodland mammal species. Examination of our data suggests that an increase in overstory cover from 0% to 30% red cedar can change a species-rich prairie community to a depauperate community dominated by 1 species, Peromyscus leucopus. Losses in species diversity and changes in mammal distribution paralleled those seen in avian communities invaded by eastern red cedar. Our results highlight ecological effects of invasion by eastern red cedar on diversity and function at multiple trophic levels.

Although historic records of the alligator snapping turtle, Macrochelys temminckii, show a past distribution throughout eastern Oklahoma, little is known about the current status and distribution of this species in the state. In 1997, surveys were initiated to identify extant populations of M. temminckii and assess their relative densities and viability. We surveyed 67 sites in 15 counties, with a total effort of 1,085 net nights. A total of 63 M. temminckii was captured at 11 sites, which are only in the southeastern quarter of the state and occur only in protected or isolated locations. Because of this apparent decrease of the range of this species in Oklahoma and because so few sites exhibited capture rates high enough to suggest possible healthy populations, we conclude that dramatic population declines of M. temminckii have taken place in Oklahoma. Possible reasons for these declines include overharvest and habitat alteration.

Increased abundance and distribution of eastern redcedar (Juniperus virginianus), a native species in the Great Plains, has been associated with changes in ecosystem functioning and landscape cover. Knowledge of the main consumers and dispersal agents of eastern red cedar cones is essential to understanding the invasive spread of the species. We examined animal removal of cedar cones in three habitats (tallgrass prairie, eastern red cedar and woodland-prairie margins) in the Cross Timbers ecoregion using three exclosure treatments during autumn and winter. Exclosure treatments excluded study trees from ungulates, from terrestrial rodents and ungulates or from neither (control). Loss of cones from branches varied by a habitat-time interaction, but was not affected by exclosure type. Loss of cones from containers located under experimental trees varied by a habitat-treatment-time interaction. In December and January, cone consumption from containers in no-exclosure treatments was highest in margins...

We assessed breeding-pair density and habitat associations of Barred Owls (Strix varia) at the edge of their range in north-central Oklahoma in 1995–1996. We played taped calls of Barred Owls to solicit and record responses (visual and auditory) and thereby determine density in our 1155-ha study area. Numbers of owls ranged from 7 pairs in 1995 to 11 pairs in 1996, or 1 Barred Owl pair/105–165 ha in a relatively contiguous bottomland forest. To assess habitat associations, we overlaid core areas of owl activity, as inferred from the locations of Barred Owl responses, on aerial photographs and quantified habitats in a 0.65-km2 cell surrounding owl core areas. Barred owl pairs were associated with closed-canopy forest (62.8%), fallow agricultural fields (10.6%), water (8.1%), and treeless (open) areas (6.2%), which differed from single owls (presumed nonbreeders) that showed a greater affinity for open-canopy forest and agricultural fields.

Trees and other woody plants threaten grassland obligate birds, as well as the biological integrity of grasslands around the world. Bird species associated with grasslands of southern mixed-grass p...

Feeding habits of the endangered Ozark big-eared bat (Corynorhinus townsendii ingens) in eastern Oklahoma, USA, were studied from July 1987 through July 1988. Diets were determined from microscopic analysis of fecal pellets and compared with arthropods collected in Malaise traps. Although lepidopterans comprised only 21.5% of the available prey, they occurred in > 90% of the pellets examined and accounted for > 85% of the volume of prey consumed. Dipterans, coleopterans, and homopterans occurred in 18.3%, 10.6%, and 6.7% of the feces, respectively, but each accounted for < 5% of the volume of prey consumed. Trichopterans, hymenopterans, and neuropterans also were found in feces but in trace amounts. Our results support the classification of C. t. ingens as a moth specialist, but additional insights are needed to fully understand how its feeding tactics conform to the allotonic frequency hypothesis (i.e., avoiding detection by eared moths). Conservation of this highly endangered North American bat will require, in part, maintenance of habitats capable of supporting abundant populations of Lepidoptera.

Home ranges of lesser prairie-chickens (Tympanuchus pallidicinctus) include up to several thousand ha of several habitat types that are concentrated around leks (traditional display grounds). A geographic information system (GIS) was used to relate changes in vegetation and land use to population trends of lesser prairie-chickens in Oklahoma, Texas and New Mexico. We quantified changes in vegetation within 4.8 km of lesser prairie-chicken leks and examined relationships among those changes and long-term population trends based on the number of displaying males per lek. Five of 13 populations declined between 1959 and 1996. Landscapes in which populations of lesser prairie-chickens declined were characterized by greater rates of landscape change and greater loss of shrubland cover types than landscapes in which populations did not decline. Changes of specific cover types were not as important as the total amount of change occurring on landscapes. Conservation of lesser prairie-chickens should focu...

Snowy Plover (Charadrius alexandrinus) nests (n = 415) were monitored to completion on an expansive alkaline flat in north-central Oklahoma in 1995–1996. We reported Mayfield Method nesting success but relied on apparent nesting success to compare differences in successful (hatched) and lost (depredated/flooded) nests in five 1000-ha areas, by microhabitat type, and inside versus outside electric-fence predator exclosures. Apparent nesting success differed by area in 1996 and over both years. Predation differed by area only in 1995, and flooding did not differ by area. Apparent nesting success and predation differed by microhabitat type in 1995 and over both years. Differences were observed among depredated and flooded nests inside versus outside electric-fence predator exclosures. Canids and gulls were primary predators. Nests associated with habitat improvements (1995) and near driftwood debris (1996) encountered higher predation, and nests near driftwood debris were more susceptible to flooding both years. We identified an area on the alkaline flat with the highest nesting success and lowest predation where future conservation efforts for Charadriiformes could be implemented.

We measured habitat characteristics in colony sites and at nest sites of endangered least terns (Sterna antillarum athalassos) on an expansive alkaline flat at Salt Plains National Wildlife Refuge, Oklahoma, in 1992 and 1993. Least terns nested in 12 colony sites on the alkaline flat during 1992 and 1993. Number of nests per colony site ranged from 5–25 and density of nests ranged from 0.1–0.75 nests/ha. Density of least terns in colony sites ranged from 0–2.1 terns/ha and was not correlated with soil color (P = 0.66) or soil texture (P = 0.12). Only a small percentage of ground cover was provided by vegetation (0.0–1.2%), driftwood (0.0–0.4%) and debris (0.0–1.1%) in colony sites. Least terns selected nest sites with coarser soil (loamy sand to sandy loam) than that of random points (P ≤ 0.0003). The coarser soils were lighter in color (P = 0.0001). Least tern nests were closer to driftwood or debris than random points (P = 0.0001). Internest distances in active colony sites ranged from 21.4 to ...

Inferences on competitive interactions between white-tailed deer Odocoileus virginianus (Zimmermann, 1780) and cattle were made using information on diet composition and quality. We hypothesized that dietary overlap between deer and cattle would increase with cattle density and that quality of deer diets would be higher in areas not exposed to cattle than in areas that were stocked with moderate to high cattle densities. Three treatments were delineated in McCurtain County, Oklahoma (heavy cattle stocking), and Howard (moderate to light cattle stocking) and Pike (no cattle stocking) counties, Arkansas. Treatments were similar with respect to soils and vegetation but differed with respect to cattle stocking rate (ie number of cattle/ha). Deer and cattle diets and concentrations of fecal nitrogen (FN) (an index to dietary quality) were determined from feces that were obtained from 12 randomly selected collection areas (4/treatment) from October 1986 to October 1988. Dietary overlap of deer and cattle was highest in winter and lowest in summer. Dietary overlap of deer populations was lowest for populations exposed to heavy cattle stocking and no cattle stocking, which suggested that competition between the deer and cattle occurred in winter. Fecal nitrogen was lowest in deer feces collected from treatments with cattle stocking in February but higher in August and October. Both dietary quality and dietary overlap suggested possible competitive interactions between deer and cattle in winter. However, higher dietary forb and dietary quality for deer in summer exposed to cattle suggested that cattle can facilitate growth of early successional plant species in pine habitats.

Foraging activity of the endangered Ozark big-eared bat ( Plecotus townsendii ingens ) was studied in June and July 1988. Adult females were equipped with radiotransmitters and tracked during lactation. Bats foraged various directions from the maternity cave and demonstrated considerable site specificity. Females went on three feeding bouts during early lactation and returned to the maternity cave after each. Number of nightly visits to the cave decreased as offspring matured, and by late July, females exited after sunset and did not return until sunrise. Average distances to foraging sites also increased as lactation progressed. Individuals used from one to four foraging sites. Ozark big-eared bats did not use habitats randomly; edge habitats of intermittent streams and mountain slopes were used more than expected based upon relative availability of habitats.

Carbon (δ13C) and nitrogen (δ15N) isotopes in biological samples from large herbivores identify photosynthetic pathways (C3 vs. C4) of plants they consumed and can elucidate potential nutritional characteristics of dietary selection. Because large herbivores consume a diversity of forage types, δ13C and δ15N in their tissue can index ingested and assimilated diets through time. We assessed δ13C and δ15N in metabolically active liver tissue of sympatric mule deer ( Odocoileus hemionus ) and white-tailed deer ( O. virginianus ) to identify dietary disparity resulting from use of burned and unburned areas in a largely forested landscape. Interspecific variation in dietary disparity of deer was documented 2–3 years post-fire in response to lag-time effects of vegetative response to burning and seasonal (i.e., summer, winter) differences in forage type. Liver δ13C for mule deer were lower during winter and higher during summer 2 years post-fire on burned habitat compared to unburned habitat suggesting different forages were consumed by mule deer in response to fire. Liver δ15N for both species were higher on burned than unburned habitat during winter and summer suggesting deer consumed more nutritious forage on burned habitat during both seasons 2 and 3 years post-fire. Unlike traditional methods of dietary assessment that do not measure uptake of carbon and nitrogen from dietary components, analyses of stable isotopes in liver or similar tissue elucidated δ13C and δ15N assimilation from seasonal dietary components and resulting differences in the foraging ecology of sympatric species in response to fire.

Tetracerus quadricornis (de Blainville, 1816) is 1 of the smallest Asian bovids and commonly is called the four-horned antelope or chousingha. It is endemic to Peninsular India and small parts of lowland Nepal. T. quadricornis is a sexually dimorphic boselaphid of small stature; only males have horns, with 2 of the 3 recognized subspecies having 2 anterior and 2 posterior smooth, sharp horns, unique among wild horned mammals. Tetracerus is monotypic. It prefers dry deciduous forested habitat and hilly terrain and is secretive and little studied. This diminutive species is considered Vulnerable by the International Union for Conservation of Nature and Natural Resources, and it is very uncommon in captivity.

The impact of habitat alterations created by five brush-management systems (herbicide applications with or without burning) on Cuterebra sp. infestations of a host community ( n = 811) of small mammals was examined on typical cross-timbers rangeland in Payne Co., Oklahoma, from summer 1986 to 1988. Prevalence of Cuterebra sp. infestations in host communities inhabiting pastures treated with tebuthiuron was greater than those treated with triclopyr in 1986. Prevalence on unburned pastures was greater than annually burned herbicide-treated pastures in 1986. Intensity of infestation was not influenced by habitat modification. Burning might have killed soil-dwelling larvae, and tebuthiuron treatment probably created an abundance of topographical summits for aggregation of Cuterebra sp.

Schweitzer, Sara H.; Finch, Deborah M.; Leslie, Jr., David M. 1998. The brown-headed cowbird and its riparian-dependent hosts in New Mexico. General Technical Report RMRS-GTR-1. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 23 p. Numbers of brown-headed cowbirds (Molothrus ater) are increasing in some regions of North America, while certain populations of long-distance, neotropical migratory songbirds (NTMs) are declining. In the Southwestern United States, several species of NTMs nest only in riparian habitats. The significant decline of two species of NTMs dependent upon riparian habitat, the southwestern willow flycatcher (Empidonax traillii extimus) and the least Bell’s vireo (Vireo bellii pusillus), is of great concern. Brood parasitism by the brown-headed cowbird and loss of riparian habitat may be the primary causes of the decline of these populations. Extant data on the distribution, abundance, density, and rates of parasitism of the brown-headed cowbird in New Mexico have not been synthesized and interpreted. Our goal was to collect and review existing data on the brown-headed cowbird in New Mexico, compare them to data from adjacent western states, and interpret the findings. We hypothesized that increased human use of riparian habitats in New Mexico had resulted in increased abundance of brown-headed cowbirds and their parasitism on riparian-dependent NTMs. Our results suggest that quantitative studies should be conducted to determine the distribution, abundance, density, and rates of parasitism of brown-headed cowbirds in New Mexico’s riparian habitats because existing data are inadequate. Results of such studies will allow conclusions to be made about the multiplicative effects of riparian habitat use and modification by human activities on cowbird and rare NTM populations.

Dendroica cerulea (Cerulean Warbler) is a migrant songbird that has declined rangewide in recent decades. We surveyed 150 sites in 2006–2007 to determine if this species still occupied its former breeding range in Oklahoma. We located Cerulean Warblers at 5 sites and confirmed breeding on north slopes of two heavily forested ridges in the Ouachita Mountains. We did not encounter Cerulean Warblers in any bottomland hardwoods, despite the former widespread distribution and abundance of the species in such habitats. While habitat loss and degradation may limit occurrence of Cerulean Warbler in some areas, the pattern of decline for this species at the edge of its range in Oklahoma is also consistent with abandonment of peripheral range as the range-wide population declines.

Pantholops hodgsonii (Abel, 1826) is a bovid commonly called the chiru or Tibetan antelope. Pantholops is monotypic. This species inhabits high-elevation alpine and desert steppe with flat to rolling terrain in the Tibetan Plateau and only recently has been studied in any detail. At least 5 populations of P. hodgsonii are migratory, some moving up to 300–400 km; others are nonmigratory. This species is endangered because of exploitation and competition with domestic livestock of pastoralists; extant populations probably number about 100,000. It is virtually unknown in zoos, but young have been born and orphans have been reared successfully in a 200-ha fenced enclosure in native habitat.

We studied habitat use of shorebirds (Charadriiformes) at a wetland experiencing natural fluctuations in water levels located at Tishomingo National Wildlife Refuge in the south-central Great Plains. We describe use of macrohabitats (disturbed, deciduous, snags, and mudflat) and microhabitats (dry-land, wet-land, and water) by foraging groups (terrestrial-aquatic gleaner, small aquatic prober-gleaner, aquatic gleaner). Water level was correlated with shorebird abundance. The small aquatic prober-gleaner group comprised 85.9% of the total shorebird community. Shorebirds selected mudflat macrohabitats (P < 0.05) and avoided disturbed, deciduous, and snags. All shorebird groups selected water microhabitat, except for the small aquatic prober-gleaner group that selected wet-land microhabitat (P < 0.05). There was a negative correlation (r s = -0.36, n = 58, P = 0.005) between pool level and number of shorebirds per survey. The relationship of water level and shorebird abundance may have more impact in an unmanaged wetland than managed wetlands. Tishomingo National Wildlife Refuge may be an important stopover site for small aquatic probes-gleaner species (e.g., western sandpipers, Calidris mauri) that require many stops along their migration routes.

Previous authors have described nesting habitat of the northern bobwhite (Colinus virginianus) throughout its range, but few have compared structural or compositional differences of vegetation between nest sites and random non-use sites, and successful and non-successful nests. From 1996-1998, we compared cover and structure of 85 plant species from 80 nest sites of northern bobwhite in western Oklahoma. Nest sites were consistently associated with greater structural complexity than what was available at random. Bobwhites selected nest sites with a greater coverage of grass (ca. 50%) and woody (ca. 20-30%) vegetation with a relatively low percentage of bare ground, presumably because these attributes maximize their chance for successful reproduction by providing protection against weather and predators. Successful nests were more concealed during 1996 and 1997 (12.37 and 10.74% visibility, respectively) than non-successful nest sites (21.6 and 27.65% visibility), but levels of concealment did not differ during 1998. We found no significant differences in vegetation composition or structure between successful and non-successful nest sites. DOI:10.2458/azu_jrm_v54i3_townsend

Seasonal habitat use by white-tailed deer (Odocoileus virginianus Zimmerman) was monitored with radio telemetry in 1988-89 to determine responses to experimental brush treatments, 5-6 years post-treatment, in the cross timbers region of central Oklahoma. The study area was a mosaic of brush treatments: tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiazol-2-yl 1]-N,N'-dimethylurea) herbicide, tebuthiuron with an annual spring burn, triclopyr ([(3,5,6-trichlor-2-pyridinyl)oxy]acetic acid) herbicide, triclopyr with an annual spring burn, and no herbicide with annual spring burning. Control areas with no burning or herbicide applications also were evaluated. Herbicides were applied in 1983, and fires were initiated in 1985. Annual home range (95% harmonic mean) averaged 99.9 ha, and no differences in size among seasons or between sexes were observed. Both sexes selected and avoided specific brush treatments throughout the year. Female deer selected or avoided more human-altered habitats in specific contrasts of main treatment groups (e.g., treated vs. control, herbicide vs. no herbicide, fire vs. no fire, etc.) than males. Both sexes selected fire treatments in summer and were most particular in their choice of main treatment groups in summer and fall habitat use between the sexes was most similar in winter and most disparate in fall. The mosaic of habitat types resulting from the variable herbicide and burn application pattern probably influenced deer habitat use in the cross timbers region through combined effects of increased mid-story cover and forage production as they relate to reproductive activities and nutritional needs of female deer in particular.

Knowledge of the habitat requirements of the Ozark big-eared bat (Plecotus townsendii ingens) is limited but is critcally important to recovery objectives for this endangered subspecies. We studied habitat use and foraging activity by P t. ingens during October 1991 and August and September 1992. Fourteen females and six males were fitted with radiotransmitters. Intraand intersexual comparisons showed no differences in median distances to foraging areas, median size of foraging areas, or number of foraging sites per bat. Late emergence times and frequent periods of inactivity during October 1991 may have been due to cold weather. Females traveled shorter distances to foraging sites and used smaller foraging areas than females previously studied during the maternity season. Females used habitats in proportion to their availability, but males used forest habitat more than expected in September. Habitat use likely was determined by prey distribution because P t. ingens has high flight maneuverability and thus would not be restricted in its use of habitat types. Our results suggest that recovery efforts that include habitat conservation should focus on areas within a radius of 8 km from caves used by P t. ingens, but additional research on movements and habitat use at other times of the year are needed to assure recovery biologists that all critical habitats are identified.

Several studies have focused on the relationship between habitat structure and the location of red-cockaded woodpecker (Picoides borealis) cavities; however, they were conducted in forests dominated by pines 100 years old. Thus, we wanted to measure the habitat structure at red-cockaded woodpecker cavity-tree sites, non-use sites, and systematically located (hereafter called systematic) sites in old-growth timber on the McCurtain County Wilderness Area, Oklahoma

We censused breeding nongame birds on replicated 5- and 6-year post herbicide-treated (tebuthiuron and triclopyr) and untreated cross timbers rangeland in central Oklahoma. Twenty species of breeding birds were observed. No treatment effects were detected for total bird density, species diversity, or richness; however, species composition varied considerably among treatments. Control sites supported species associated with closed canopy woodlands, and treated sites supported species associated with brushy and prairie habitat. Generally, control sites had greater foliar cover, fewer snags, and less slash and herbaceous cover than treated sites. Densities of 6 of the 7 most abundant bird species were correlated variously with habitat variables. We concluded that changes in habitat structure resulted in differences in bird species composition among treatments.