The raccoon, Procyon Iotor, in Wyoming

Recent distribution maps show raccoon as occupying only the extreme eastern - northeastern portion of Wyoming. However, there is substantial evidence that raccoon are common throughout Wyoming and currently inhabit all the major and many of the minor drainages throughout Wyoming.     

Survey of Wyoming crayfishes

Collections of crayfish by Wyoming Game and Fish Department biologists and University of Wyoming staff in 1985-1987 included five species: Pacifastacus gambelii , the only species found in the Snake River and Bear River drainages of western Wyoming; Orconectes neglectus neglectus , collected from one reservoir in the South Platte River drainage in southeastern Wyoming (its first reported occurrence in the state); O. immunis and O. virilis ,widespread east of the Continental Divide and in the Green River drainage of southwestern Wyoming; and Cambarus Diogenes Diogenes , collected from a tributary of the North Platte River in eastern Wyoming.     

Passerine response to roads associated with natural gas extraction in a sagebrush steppe habitat

Natural gas extraction and field development are pervasive throughout the sagebrush steppe of Wyoming. We conducted this study to determine how roads associated with natural gas extraction affect the distribution of breeding songbirds in sagebrush steppe habitat. The study encompassed dirt and paved roads in the Jonah Field II and Pinedale Anticline Project Area in Sublette County, Wyoming. Sites are dominated by Wyoming big sagebrush ( Artemisia tridentata ), and common passerines include sagebrush obligates: Brewer's Sparrows ( Spizella breweri ), Sage Sparrows ( Amphispiza belli ), and Sage Thrashers ( Oreoscoptes montanus ); and non-obligates: Horned Larks ( Eremophila alpestris ) and Vesper Sparrows ( Pooecetes gramineus ). Species relative density was measured using 50-m-radius point counts during spring 1999 and 2000. Four roads with low traffic volumes (700-10 vehicles per day) were surveyed and point counts were centered at variable distances from the road surface such that relative densities were measured 0-600 m from the road's edge. Density of sagebrush obligates, particularly Brewer's and Sage Sparrow, was reduced by 39%-60% within a 100-m buffer around dirt roads with low traffic volumes (700-10 vehicles per day). While a 39%-60% reduction in sagebrush obligates within 100 m of a single road may not be biologically significant, the density of roads created during natural gas development and extraction compounds the effect, and the area of impact can be substantial. Traffic volume alone may not sufficiently explain observed declines adjacent to roads, and sagebrush obligates may also be responding to edge effects, habitat fragmentation, and increases in other passerine species along road corridors. Therefore, declines may persist after traffic associated with extraction subsides and perhaps until roads are fully reclaimed.     

Additions to the vascular flora of Wyoming

Eight species previously unreported for Wyoming are listed. A range extension is noted for Erigeron humilis, and Cymopterus bipinnatus is verified as occurring in Wyoming.     

Early brood-rearing habitat use and productivity of Greater Sage-Grouse in Wyoming

Populations of Greater Sage-Grouse ( Centrocercus urophasianus ) have been declining throughout their range since the 1960s. Productivity, which includes production and survival of young, is often cited as a factor in these declines. We monitored radio-equipped Greater Sage-Grouse at 3 sites in western Wyoming to assess early brood-rearing habitat use (through 14 days post-hatch) and productivity. Logistic and linear regression analyses with Akaike's Information Criterion were used to evaluate early brooding habitat use and to examine relationships between productivity and vegetation, insect size and abundance, and weather parameters. Females with broods were found in areas with greater sagebrush canopy and grass cover, and fewer invertebrates compared to random areas. The number of juveniles per female (estimated from wing barrel collections during fall harvest) was positively related to the abundance of medium-length Hymenoptera and grass cover, and the proportion of females with confirmed chicks 14 days post-hatch was positively related to abundance of medium-length Coleoptera and total herbaceous cover. Although the specific parameters varied slightly, Greater Sage-Grouse productivity in Wyoming appeared to be associated with a combination of insect and herbaceous cover elements. Managing for abundant and diverse insect communities within dense protective sagebrush stands should help ensure high-quality early brood-rearing habitat and increased Greater Sage-Grouse productivity.     

Helminth parasites of the Wyoming ground squirrel, Spermophilus elegans Kennicott, 1863

Helminth parasites of the Wyoming ground squirrel, Spermophilus elegans Kennicott, 1863, were surveyed from two environmentally different habitats within Wyoming. A total of four helminth species were identified. Three helminth species were found in 419 hosts collected in a mesic habitat including one species of adult cestode, Hymenolepis citelli, and two species of nematodes, Citellinema bifurcatum and Syphacia citelli. Only larval cestodes ( Taenia taxidiensis ) were found infecting 335 Wyoming ground squirrels collected from a xeric habitat.     

Current status and distribution of the Ciconiiforms nesting in Wyoming

Five species of Ciconiiforms breed in Wyoming: the American Bittern ( Botaurus lentiginosus ), Great Blue Heron ( Ardea herodias ), Snowy Egret ( Egretta thula ), Black-crowned Night-Heron ( Nycticorax nycticorax ), and White-faced Ibis ( Plegadis chihi ). Field surveys conducted from 1984 through 1986 indicate that at least 151 Great Blue Heron colony sites exist in Wyoming, making it the most abundant and widespread Ciconiiform in the state. Only small breeding populations have been discovered for the remaining species. Except for the Snowy Egret, where numbers of active nests have remained relatively stable, population trends are unknown for the other species. We believe most colonies have been found in Wyoming, but additional inventories may result in the discovery of other nesting areas, especially for the Great Blue Heron.     

Species of Eimeria from the thirteen-lined ground squirrel, Spermophilus tridecemlineatus , from Wyoming

Five species of the coccidian genus Eimeria ( E. beecheyi [prevalence = 17.9%], E. callospermophili-morainensis [28.6%], E. larimerensis [16.1%], and E. bilamellata [3.6%]) were recovered from 56, 13-lined ground squirrels ( Spermophilus tridicemlineatus ) collected from two sites in eastern Wyoming. Two squirrels from one site were also passing an unidentified polysporocystic coccidian. Infected squirrels were found to harbor from one to three species simultaneously. Previously these same eimerian species were found infecting sympatric populations of Wyoming ground squirrels. ( Spermophilus elegans ) and white-tailed prairie dogs ( Cynomys leacurus ) at one of the sites; it is suggested that the exchange of these generalist parasite species among co-occurring sciurid hosts contributes to the consistent prevalence levels reported in Wyoming ground squirrels.     

Model of breeding habitat of the Mountain Plover ( Charadrius montanus ) in western Wyoming

To aid the conservation and management of Mountain Plovers ( Charadrius montanus ), we developed a spatially explicit model of breeding habitat for the shrub-steppe of western Wyoming. Points of Mountain Plover presence and absence were determined by field surveys conducted May through June 1999. At each point we measured topographic slope and a cover type suitability index related to vegetation height and density. Logistic regression revealed a strong negative relationship between presence and slope, and a weaker and positive relationship between presence and cover index. A multiple logistic regression model using slope and cover index to predict presence successfully classified 87% of the points in an independent data set covering much of western Wyoming. The spatial expression of this model will help managers target future surveys and identify currently unsuitable habitat that could be improved via vegetation management. Patches of suitable breeding habitat of the Mountain Plover in western Wyoming are probably functions of poor soil, low precipitation, and wind scour, and thus are likely rather persistent in space and time. Combined with the relatively large proportion of publicly owned land here, this may make conservation and recovery of the Mountain Plover easier in western Wyoming than in the more dynamic and privately controlled Great Plains.     

Distributional information on birds from egg sets collected by Henry Rogers Durkee in 1870 in southwestern Wyoming

Henry Rogers Durkee collected 74 egg sets of 27 avian species in 1870 at Gilmer, Uinta County, in southwestern Wyoming. Despite the paucity of documented breeding evidence from this region during the late 19th and early 20th centuries, his material at the Smithsonian Institution was generally overlooked and has never been critically examined. Durkee's egg sets included 5 species (Sandhill Crane, Grus candensis ; Northern Rough-winged Swallow, Stelgidoteryx serripennis ; Grasshopper Sparrow, Ammodramus savannarum ; Fox Sparrow, Passerella iliaca ; Cassin's Finch, Carpodacus cassinii ) whose breeding distribution was then poorly known, 25 to more than 70 years before nests and eggs were otherwise documented in Wyoming. Durkee also collected complete egg sets of Lark Bunting ( Calamospiza melanocorys ) over 70 years before breeding was confirmed at other peripheral locations in Wyoming. In addition, Durkee's incomplete egg sets of Grasshopper Sparrow were the 1st western subspecies ( A. s. perpallidus ); his complete egg set and nest of the Fox Sparrow collected at Gilmer constituted the 2nd locality for the species or species group ( P. i. schistacea ). Although the number of egg sets Durkee collected is modest, he made a meaningful contribution to the early history of avifaunal exploration in Wyoming.     

A taxonomic evaluation of Elymus simplex (Poaceae)

An investigation was made of Elymus simplex to evaluate the current taxonomy and cytology. The study included herbarium specimens from Wyoming and Colorado and population samples from the type location in Wyoming. The most important taxonomic characters noted are: numbers of spikelets per node, lemma awn length, and habitat. The chromosome number of E. simplex is reported as 2 n =28. E. simplex is a distinct species and should not be confused with E. salina, from which it differs morphologically.     

Ecological classification and monitoring model for the Wyoming big sagebrush shrubsteppe habitat type of northeastern Wyoming

The purposes of this study were to develop a multivariate statistical model related to plant succession, to classify by seral stage, and to monitor succession in Wyoming big sagebrush shrubsteppe habitat ( Artemisia tridentata ssp. wyomingensis / Agropyron smithii–Bouteloua gracilis ) in Thunder Basin National Grassland, Wyoming. This model can be used by range and wildlife managers to evaluate management alternatives by assessing changes in plant species cover and composition within and between seral stages. Four ecological seral stages that represent early to late succession were quantitatively identified with an estimated 92% accuracy. Three key plant species provided the necessary information to define seral stages and monitor trends. Percent canopy cover and percent frequency (used to calculate index values: % canopy cover × % frequency of occurrence) of Wyoming big sagebrush ( Artemisia tridentata ssp. wyomingensis ), western wheatgrass ( Agropyron smithii ), and blue grama ( Bouteloua gracilis ) are the only field measurements required for this model.     

Status and distribution of the Laridae in Wyoming through 1986

To date, 17 species of Laridae have been reported in Wyoming. Six of these species have know breeding populations in the state: the Ring-billed Gull ( Larus delawarensis ), California Gull ( Larus californicus ), Herring Gull ( Larus argentatus ), Caspian Tern ( Sterna caspia ), Forster's Tern ( Sterna forsteri ), and Black Tern ( Chlidonias niger ). Of these species, the California Gull is the most abundant and widespread. In 1984 approximately 7300 nests existed in Wyoming at six breeding locations consisting of 10 different colonies. In contrast, only small breeding populations have been discovered for the remaining five species. The Herring Gull is the most recent addition among Laridae know to nest in Wyoming. Likewise, two Ring-billed Bull colonies were recently found after not having been documented as breeding in the state for over 50 years. Although some nesting colonies are threatened by habitat loss and human disturbance, most seem secure at present. Limited nesting and foraging habitat precludes establishment of large breeding populations of most Laridae in the state.     

Comparison of Sage and Sharp-tailed Grouse leks in south central Wyoming

Columbian Sharp-tailed Grouse ( Tympanuchus Phasianellus columnianus ) and Sage Grouse ( Centro-cercus urophasianus ) leks were compared in an area of sympatry in south central Wyoming. Sharp-tailed Grouse leks had more (P < .05 shrub cover, taller shrubs, more forb, grass, and shrub species, and less visibility than did Sage Grouse leks. Reduction in shrub cover or the diversity of herbaceous species could potentially have greater influence on the use of lek sites by Columbian Sharp-tailed Grouse than by Sage Grouse in areas of sympatry in Wyoming.     

Synopsis of the mosses of Wyoming

A revised list of the mosses of the State of Wyoming is presented. Recorded are 315 species and varieties.     

Records of exotic fishes from Idaho and Wyoming

One exotic poeciliid ( Xiphophorus helleri ) and two cichlids ( Cichlasoma nigrofasciatum and Tilapia mossambica ) are recorded as recently established in thermal springs and their outflows in southern Idaho. Misgurnus anguillicaudatus was collected and is considered as established in the Boise River system. Poecilia mexicana and juvenile hybrid tilapias are recorded from the Bruneau River at Bruneau Hot Springs, Idaho. A reproducing population of X. helleri was found in a spring within the boundaries of Grand Teton National Park, Wyoming. Poecilia reticulata , previously reported from one spring each in Idaho and Wyoming, is recorded from a second spring outflow in Idaho.     

Additions to the vascular flora of Montana and Wyoming

A list of one taxon new for Montana and 10 new for Wyoming is presented, plus comments about Astragalus molybdenus.     

Status and distribution of American White Pelican nesting colonies in Wyoming: an update

Historically, one American White Pelican nesting area was known in Wyoming. In 1986 White Pelicans nested at four locations consisting of four different colonies and approximately 949 active nests. Nesting success was probably adequate for population stability at Pathfinder Reservoir from 1984 through 1986 and at Yellowstone Lake in 1984 and 1985, but insufficient there in 1986. White Pelican colonies at Bamforth and Cooper lakes most likely failed because of predation. With the exception of the Yellowstone Lake colony, the future of White Pelican nesting colonies in Wyoming is uncertain. Current threats are human disturbance of nesting birds, predation, and loss of habitat, including breeding areas and foraging sites.     

A small carnivore survey technique

Thirty-nine previously unpublished reports of the endangered black-footed ferret from Wyoming are listed with dates, locations, number of animals, sources, and comments.     

Additional black-footed ferret ( Mustela nigripes ) reports from Wyoming

Thirty-nine previously unpublished reports of the endangered black-footed ferret from Wyoming are listed with dates, locations, number of animals, sources, and comments.