Body fat, body water, and total caloric value of Uinta ground squirrels

The weight of body water and fat-free dry weight of Uinta ground squirrels ( Spermophilus armatus ) is given as a function of body weight. Body fat is presented as a function of body weight and body length. An equation for calculating the total caloric content of Uinta ground squirrels is given. Fat index (weight of fat/fat-free dry weight) values of juveniles increased from 0.11 to 0.22 from 5 June to 28 July. In male yearlings and adults the fat index increased about 8 to 9 times in the latter half of June and early July.         

Can Townsend's ground squirrels survive on a diet of exotic annuals?

Southwestern Idaho desert shrub-bunchgrass rangeland is being invaded by fire-prone exotic annuals that permanently dominate the landscape following wildfires. This study was undertaken to describe diets of Townsend's ground squirrels ( Spermophilus townsendii idahoensis ) at four study sites with varying degrees of exotic annual invasion to determine if the squirrels could utilize high proportions of exotic annuals in their diets. Townsend's ground squirrels were collected in March and May of 1987 and 1988, and stomach contents were analyzed using a microhistological technique. Grasses comprised 37-87% of Townsend's ground squirrel diets at the four sites. Native species, especially Sandberg's bluegrass ( Poa secunda ), winterfat ( Ceratoides lanata ), big sagebrush ( Artemisia tridentata ) and six-weeks fescue ( Vulpia octoflora ) constituted 7-96% (x = 47.2%) of the diet, whereas exotic species, especially cheatgrass ( Bromus tectorum ), tumbleweed ( Salsola iberica ), and tansymustards ( Descurainia spp.) made up 4-68% (x = 48.0%) of the diet. At each site 2-4 species comprised >90% of the diet. There was no apparent correlation between the importance values of exotic species at a site and their importance in Townsend's ground squirrel diets.     

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.     

Eimeria sp. (Apicomplexa: Eimeriidae) from Wyoming ground squirrels Spermophilus elegans , and white-tailed prairie dogs, Cynomys leucurus , in Wyoming

Six species of the coccidian genus Eimeria ( E. larimerensis [prevalence = 17%], E. bilamellata [12%] E. beecheyi [34%], E. morainensis [43%], E. callospermophili [21%], and E. spermophili [5%]) were recovered from Wyoming ground squirrels ( Spermophilus elegans elegans ) collected during 1983, 1984, 1985, and 1986. Infected ground squirrels were found to harbor from one to five species simultaneously. The 1007 hosts examined were collected from two different habitats: (1) a xeric desert shrub-steppe and (2) an irrigated alfalfa-brome field. All species of Eimeria occurred at each study site during all years, although the prevalence of each species varied between years. This is the first report of these congeries of species infecting this host. In a second study of sympatric populations of Wyoming ground squirrels and white-tailed prairie dogs ( Cynomys leucurus ), found three species of Eimeria present in both host populations ( E. beecheyi [white-tailed prairie dog prevalence = 83%, Wyoming ground squirrel = 52%], E. morainensis [22%, 52%], and E. bilamellata [17%, 10%]). This is the first report of these three species infecting white-tailed prairie dogs. Eimeria larimerensis was found in Wyoming ground squirrels but not in prairie dogs.     

Food habits and nest characteristics of breeding raptors in southwestern Wyoming

Food habits and nest site features of the Golden Eagle ( Aquila chrysaetos ), Prairie Falcon ( Falco mexicanus ), Red-tailed Hawk ( Buteo jamaicensis ), and Ferruginous Hawk ( B. regalis ) were studied near Medicine Bow, Wyoming, during 1981 and 1982. Foods consisted primarily of leporids and sciurids. The Wyoming ground squirrel ( Spemiophilus richardsonii ) dominated the diet of Prairie Falcons, while Golden Eagles preyed on leporids more than did the other raptors. Diet overlap ranged from 59 to 99% between the species. Mean height of Golden Eagle nests was greater than nest height of other species. Most raptor nests (78%) were not visible from other active nests and were in view of roads. Prairie Falcons were the most specialized and Ferruginous Hawks the most versatile raptor species in terms of food habits and use of nest sites.     

Some spatial and behavioral features of the thirteen-lined ground squirrel

Some relationships between home range, agonistic behavior, and reproductive patterns in thirteen-lined ground squirrels were investigated in Laramie Plains, Wyoming (August 1966–April 1969). Population size and densities fluctuated seasonally and annually. Adult male (N = 7) home ranges averaged 0.24 ha and were smaller than those of the female (N = 9), which averaged 0.35 ha. Agonistic interactions were more frequent during the natal period (late May–June) than during the breeding-gestation period (mid April–May). Most squirrels (86 percent) shared capture sites and had overlapping home ranges. However, a certain degree of spacing existed because of agonistic behavior.     

Reproductive cycle of the Belding ground squirrel ( Spermophilus beldingi beldingi ): seasonal and age differences

The reproductive cycle in Belding ground squirrels was studied in the Sierra Nevada Mountains at two locations, one at 2,100 m elevation, the other at 3,000 m. Adults emerged from hibernation completely prepared physiologically for reproduction. Males tended to emerge slightly ahead of females and yearlings tended to emerge later than adults. Yearling females were fertile but produced smaller litters than adults, 4.48 vs. 6.31. Yearling males were infertile. They exhibited a slight seasonal cycle in testicular growth but did not reach sexual maturity. Testicular growth and spermatogenesis were incipient in many adults and in yearlings prior to hibernation.       

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.     

Habitat and nesting biology of Mountain Plovers in Wyoming

Although previous research has considered habitat associations and breeding biology of Mountain Plovers in Wyoming at discrete sites, no study has considered these attributes at a statewide scale. We located 55 Mountain Plover nests in 6 counties across Wyoming during 2002 and 2003. Nests occurred in 2 general habitat types: grassland and desert-shrub. Mean estimated hatch date was 26 June ( n = 31) in 2002 and 21 June ( n = 24) in 2003. Mean hatch date was not related to latitude or elevation. Hatch success of nests was inferred in 2003 by the presence of eggshell fragments in the nest scrape. Eggs in 14 of 22 (64%) known-fate nests hatched. All grassland sites and 90% of desert sites were host to ungulate grazers, although prairie dogs were absent at 64% of nest sites. Nest plots had less grass coverage and reduced grass height compared with random plots. More than 50% of nests occurred on elevated plateaus. The Mountain Plover's tendency to nest on arid, elevated plateaus further substantiates claims that the bird is also a disturbed- prairie species.     

Breeding ecology of Long-billed Curlews at Great Salt Lake, Utah

We qualified nest site characteristics, breeding densities, and migratory chronology of Long-billed Curlews at the Great Salt Lake, Utah. The species is apparently declining in Utah, and little is known about their breeding in the eastern Great Basin Desert. This study was designed to provide wildlife biologist with the baseline data useful for their successful management. Curlews arrived in northern Utah in late March and generally departed by mid-August. Nest densities at Great Salt Lake ranged from 0.64 to 2.36 males/km 2 . The habitat at curlew nest sites consisted of significantly shorter vegetation than nearby random locations ( ˉx = 5.7 versus 9.0 cm, respectively; P < .01). Nests tended to be located in small patches of vegetation near barren ground. Maintenance of relatively short vegetation appears to be important in managing curlew habitat. In addition, only 2 of 10 nests we monitored in 1992 were successful, with most lost to mammalian predators. Further research is needed to determine impact of mammalian predators on curlew populations.     

Plague in pine martens and the fleas associated with its occurrence

Thirteen pine martens ( Martes Americana ) were sampled periodically from July 1979 to September 1980 for plague ( Yersinia pestis ) antibodies and their fleas collected and identified. Four individuals were positive for plague antibodies on 8 of 24 sampling occasions. Titer peaks in these individuals occurred simultaneously in early winter but fell to undetectable levels by late spring. A chipmunk flea ( Monopsyllus ciliatus ) was the most common ectoparasite constituting 55% of all individuals collected. Thirty-one percent of all fleas belonged to Chaetopsylla floridensis, a species previously unreported in California. The remains of ground-dwelling sciurids (chipmunks, Eutamias spp., and ground squirrels, Spermophilus spp.) were very common in marten scats during the period preceding elevated titers. For this reason, and the fact that 92% of all fleas collected from martens during this same period were found more commonly on chipmunks and ground squirrels, these rodents were implicated as the source of the martens&rsquo; exposure to plague.     

Indicators of red squirrel (Tamiasciurus hudsonicus) abundance in the whitebark pine zone

We investigated occupied squirrel middens and squirrel sightings and vocalizations as indicators of red squirrel ( Tamiasciurus hudsonicus ) abundance in high-elevation whitebark pine ( Pinus albicaulis ) zone. Data were collected 1984-1989 from line transects located on 2 study sites in the Yellowstone ecosystem. We evaluated the performance of each measure on the basis of precision and biological considerations. We concluded that, of the 3 measures, active middens were the best indicator of red squirrel abundance. We also observed that the density of active middens dropped by 48%-66% between 1987 and 1989, following a severe drought and extensive wildfires that burned one of the study sites during 1988.     

Aspects of Sacramento pikeminnow biology in nearshore habitats of the Sacramento-San Joaquin Delta, California

We documented distribution, relative abundance, diet composition, and body condition of Sacramento pikeminnow Ptychocheilus grandis during 2001 and 2003 at 5 sites in the Sacramento-San Joaquin Delta, California. Sacramento pikeminnow densities in nearshore habitats were higher in 2003 than 2001. In both years, spatial distribution of beach seine densities was similar. There were no significant differences in density among sampling sites except for the southernmost site where the catch was near zero. Based on rotary screw-trap data from a 6th site, we found relative abundance of Sacramento pikeminnow entering the Delta via an artificial floodplain was positively correlated with flow. Most individuals collected using all 3 gear types were age 1 or older, and appeared to grow quickly based on data from previous studies. Sacramento pikeminnow had diverse diets composed of freshwater and estuarine invertebrate and fish taxa. Incidence of piscivory was only 2% of the diet of individuals P. oregonensis , but in seeming contrast to endangered Colorado pikeminnow P. lucius , the present study showed that Sacramento pikeminnow can be successful in altered habitats. Sacramento pikeminnow; Ptychocheilus grandis; Sacramento-San Joaquin Delta; habitat use; diet composition; condition factor; Cyprinidae.     

Pleioxenous host-restriction in fleas

A review of the pleioxenous genera of fleas, those genera whose species are confined to hosts of a single family, indicates that such a restriction results from one of several situations. Genera of 10 or more taxa (species and subspecies) were considered, so as to exclude very small genera that might be relicts. Polyxenous genera, whose species occur regularly on two or more families (and frequently on two or more orders) of hosts are far more numerous than pleioxenous genera.

Bat fleas (Ischnopsyllidae) are unique in that all genera are pleioxenous. This seems to reflect the fact that most bat fleas occur on cave-dwelling bats, and that the cave provides for larval development of bat fleas. Five pleioxenous genera occur on rodents in deserts or semiarid regions. The extreme climatic changes that have been concomitant with desertification from the Mid-Cenozoic, and especially in the Pleistocene, are paralleled by the proliferation of the mammalian hosts themselves in deserts. Three pleioxenous genera are found on fossorial rodents (Geomyidae). These rodents appear to have been isolated and rejoined during climatic changes in western North America; and rapid speciation of their fleas followed speciation of the hosts. One pleioxenous genus, and others that are nearly pleioxenous, parasitize cricetine mice in Central America. It is suggested that the Cenozoic archipelago which occupied this region provided an environment for rapid speciation of both hosts and their fleas. Two pleioxenous genera are found on tree squirrels in the tropics. Although fleas of mice occasionally make permanent transfers to squirrels, as the former occupy squirrel nests, reverse transfers (from tree squirrels to mice) are rare. Two genera of fleas are restricted to murid mice in Africa south of the Sahara; this is a region in which murid mice usually outnumber species of other rodent families. One pleioxenous genus occurs on Arvicolidae, possibly a result of rapid speciation of hosts during the extreme climatic changes in boreal habitats during late Cenozoic and Pleistocene.

There is a tendency for the apparently more ancient families of fleas (e.g. Stephanocircidae, Pygiopsyllidae and Hystrichopsyllidae) to have very few pleioxenous genera but many polyxenous genera. The more modern families of fleas (e.g. Leptopsyllidae and Ceratophyllidae) contain a higher percentage of pleioxenous genera.     

Selection of microhabitat by the red-backed vole, Clethrionomys gapperi

Clethrionomys gapperi were captured in microhabitats with greater densities of overall cover than at noncapture or random sites within the study area. Variables describing cover density and distance from free water were selected in a discriminant function analysis to differentiate between vole capture and noncapture sites. Vole capture sites had greater amounts of cover within 4 dm above ground surface and were further from standing water than noncapture sites. The preferential use by C. gapperi of microhabitats with greater densities of cover is in agreement with laboratory and field assessments of habitat use reported in the literature.     

Wildlife use of Douglas-fir dwarf mistletoe witches' brooms in the Southwest

We evaluated wildlife use of witches' brooms associated with infection by Douglas-fir dwarf mistletoe ( Arceuthobium douglasii ) in 6 mixed-conifer study areas in Arizona and 2 areas in New Mexico. We climbed 153 infected Douglas-firs ( Pseudotsuga menziesii ) and examined 706 witches' brooms for evidence of wildlife use. Even though we observed evidence of use by birds, most wildlife use was by small mammals, particularly red squirrels ( Tamiasciurus hudsonicus ). Red squirrels used witches' brooms for nesting, foraging, caching, and as latrines. Witches' brooms classified as Type II or III brooms, located close to the main bole with large platforms, and 5–10 m above the ground were the most frequently used by red squirrels.     

Succession in pinyon-juniper woodlands following wildfire in the Great Basin

Twenty - one areas in pinyon ( Pinus monophylla ) - juniper ( Juniperus osteosperma ) woodlands burned by wildfire from approximately 1 to 60 years prior to sampling and adjacent unburned mature woodland stands were studied in Nevada and California to determine successional patterns and individual species responses to burning and to changing plant communities through time. One year after burning, all late successional woodland species were present in postburn plant communities except tree species. Increases in both cover and occurrence of annual and perennial forbs resulted in their dominance on early successional sites. Shrubs and annual grasses dominated midsuccessional sites, subsequently giving way to tree, shrub, and perennial grass dominance in late succession. North and east slopes generally supported high cover and occurrence of shrubs, perennial grasses, and perennial forbs, and south and west slopes generally supported high cover and occurrence of annual forbs and annual grasses. The ability to group species according to preferential occurrence on various aspects and successional stages can be used to predict plant community composition in time and space in the pinyon - juniper woodlands. &nbsp;&nbsp;&nbsp;     

Habitat use and food selection of small mammals near a sagebrush/crested wheatgrass interface in southeastern Idaho

Habitat use and food selection data were collected for deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Ord's kangaroo rats ( Dipodomys ordii ), and Townsend's ground squirrels ( Spermophilus townsendii ) near a sagebrush ( Artemisia tridentata )/crested wheatgrass ( Agropyron cristatum ) interface in southeastem Idaho. Significantly more captures occurred in the native sagebrush habitat than in areas planted in crested wheatgrass or in disturbed sites. Crested wheatgrass, a prolific seed producer, still accounted for over 30% of the total captures. Montane voles and Townsend's ground squirrels (during periods of aboveground activity) used the crested wheatgrass habitat throughout the summer, while deer mice and, Ord's kangaroo rats exhibited heavy use after seed set.     

Vegetation response to prescribed fire in Dinosaur National Monument

Much of western North America is dominated by dense, monotypic, late seral stands of big sagebrush ( Artemisia tridentata Nutt.). These stands often have depauperate understories with limited species richness, diversity, and herbaceous cover. The National Park Service at Dinosaur National Monument, Colorado, is using both strategic and natural prescribed fire in Wyoming big sagebrush ( Artemisia tridentata ssp. wyomingensis Beetle and Young) communities to foster intra-community (α -scale) and landscape diversity. This study analyzed an accumulated foliar cover data set between paired burn and control areas on 6 different sites during the last 20 years. Across the monitoring period, mean total vegetation cover of all combined sites was 44% control and 42% burn. Total vegetation cover in burn areas was higher than or equal to paired control areas within 2-3 years post-burn. Shrubs were essentially eliminated in burn areas, but perennial grass cover was 10-35% higher. Mean number of species on all sites and years combined was 17 control and 18 burn. Species richness was different on only 1 site-year, Dry Woman 1995 ( P = 0.001, 15 control, 9 burn). Species similarity by site and between treatments ranged from 44% to 75%. Differences in Shannon-Weiner diversity index values between paired sites occurred in 6 of 20 years ( P < 0.05). Index value differences on these 6 sites were due to a large annual grass component in burn areas. Prescribed burning successfully shifted late successional sagebrushdominated communities to earlier herbaceous-dominated successional stages without lowering total vegetation cover, while maintaining -scale diversity and species richness.