Marmot distribution and habitat associations in the Great Basin

In this study I describe the distribution and habitat associations of yellow-bellied marmots ( Marmota flaviventris ) in the Great Basin, compare my findings with those of E.R. Hall during his 1929-1936 survey and later surveys, and discuss potential reasons for changes in marmot distribution over time. I found 62 marmot burrow sites in 18 mountain ranges, mostly in rocky meadows situated on well-drained slopes between 2100 m and 3000 m elevation. Marmots were generally found near burrows dug within talus slopes, talus-like rock piles, or clusters of massive boulders. Oceanspray ( Holodiscus discolor ) was the shrub most commonly associated with occupied rock formations. Marmots were most abundant in the Ruby/East Humboldt Range and were common in the Desatoya, Shoshone, Toiyabe, Toquima, Cherry Creek, Schell Creek, Deep Creek, and Stansbury Ranges. Marmots appeared to be uncommon in the Monitor Range and rare in the Clan Alpine, Roberts, and Snake Ranges. I was unable to find marmots in the Diamond, Egan, Spruce-Pequop, White Pine, and Oquirrh Ranges, although I located old, weathered marmot scats in all but the latter 2 ranges. Other evidence confirms that marmots do actually occur in the Oquirrh Range, but extensive searches of the White Pine Range, including some of the same rock formations where E.R. Hall collected marmots, revealed no sign of marmots. My distribution data suggest that marmots may have gone extinct in some Great Basin mountain ranges during the last century. These disappearances may represent a natural extinction-recolonization dynamic, but a more alarming possibility is a recent die-off linked to climate change, which is predicted to force montane vegetation zones further upslope, shrinking the habitat of associated faunas. However, marmots in this study were observed as low as 1550 m elevation, indicating an altitudinal flexibility that may allow this species to survive climatic change better than more specialized boreal species such as pikas ( Ochotona princeps ) and water shrews ( Sorex palustris ).     

Diets of sympatric red foxes and coyotes in southeastern Idaho

Scats of sympatric red foxes and coyotes from the upper Snake River Plain of southeastern Idaho were analyzed for composition. Rodent remains in general and those of cricetid mice in particular occurred more frequently in scats of red foxes during all seasons of the year than any other food items identified. Scats of coyotes differed significantly in content from scats of red foxes during winter and contained primarily pygmy rabbit remains. In summer, remains of pygmy rabbits, sheep, ground squirrels, yellow-bellied marmots, arthropods, and vegetation were formed more frequently in scats of coyotes and remains of cricetid mice occurred more frequently in scats of red foxes. Red foxes and coyotes generally consumed similar food items but in different proportions. Based on the location of scats that were collected, red foxes and coyotes largely used different portions of the study area. Reasons for the preferential usage of habitat are discussed.     

Selection of ants by the American black bear ( Ursus americanus )

We examined selection of ants as food by black bears ( Ursus americanus ) in Utah by comparing the genera of ants we sampled from study plots in 5 vegetation types with those found in bear scats. In the plots we found 641 ant colonies representing 18 genera. Five genera comprised 85% of all colonies sampled: Formica, Lasius, Camponotus, Tapinoma, and Myrmica . Thirteen genera were found in scats, but 99% were composed of the same 5 listed above. Limited utilization of some ant genera by black bears may reflect body size, colony size, nest type, and presence or absence of a functional sting. Fifty-three percent of all ant colonies in sample plots were found under rocks. Energy values of ants ranged from 4.9 to 6.2 cal · g -1 dry weight. Pupae of Formica and Camponotus contained slightly more fat than respective workers, but the relationship was reversed for Lasius . Pupal cases were found in 33% of the scats, and bears may prefer ant brood because they are more digestible than adults and lack mechanisms of defense. Ants are a predictable and ubiquitous food source for black bears.     

American pikas inhabit low-elevation sites outside the species’ previously described bioclimatic envelope

It has been suggested that Nearctic pikas ( Ochotona spp.) are good biogeographic indicators of regions containing rocky, mesic, and cool habitat characterized by long winters and short summers. I examined whether populations of pikas inhabiting distinct low-elevation locales (121–255 m) are faithfully restricted to long-winter and shortsummer conditions by monitoring the climate associated with American pikas ( Ochotona princeps ) in the southern part of the Columbia River Gorge, Oregon. Ambient air temperatures and weather conditions in the vicinity of 4 pika-occupied rockslides were monitored with remote temperature loggers and weather stations from June 2000 to June 2001. Temperatures were compared to long-term averages recorded within the area. I detected pikas inhabiting locales where some temperatures lie outside of the limiting climatic values previously calculated for regions containing pikas. Mild winter temperatures at these pika locations show that long-winter temperatures and snow accumulation associated with typical habitat may not be requirements for pikas in some low-elevation habitat. When using climatic conditions experienced by extant pikas to estimate local paleoenvironments surrounding fossil sites and to anticipate effects of climate change on future pika distributions, I determined that pika sites in the Columbia River Gorge indicate that the association of pikas with long-winter habitat should be considered uncertain. These results highlight the need for further investigation into how local temperatures affect the distribution, behavior, and persistence of low-elevation pikas.     

Factors affecting selection of winter food and roosting resources by porcupines in Utah

Ecological and phytochemical factors potentially affecting winter dietary discrimination by porcupines ( Erethizon dorsatum ) in the mountain brush zone of Utah were studied. Porcupines utilized gambel oak ( Quercus gambelii ) as their primary winter food and roosting resource. Big-tooth maple ( Acer grandidentatum ) was the most common tree species in the study area but was rarely utilized by porcupines. Conifer species were used as a food and roosting resource significantly less often than they occurred in the study area, despite thermal advantages provided by their relatively dense canopies. Oak feed trees were successfully separated from conifer feed trees by discriminant analysis 100% of the time. Oak trees were correctly classified as feed and nonfeed trees 71% of the time. Gambel oak contained higher amounts of crude protein, fiber, and tannins, but was lower in either extract fractions and fatty acid content than conifers. A layer of adipose tissue used as an energy reserve by porcupines may have relaxed energy intake demands sufficiently to permit them to concentrate on a diet of oak tissue, which is high in protein, rather than a high-fat conifer diet. A diet relatively high in protein may have facilitated digestion of food material high in fiber. Temperature did not affect selection of tree species for roosting. Rock and snow caves were utilized infrequently and the study population ranged widely. Three of 15 study animals were eaten by predators.     

Gray fox and coyote abundance and diet responses after a wildfire in central Arizona

There is a paucity of information on the effects of wildfire on carnivores. We studied the effects of a 237-km 2 catastrophic wildfire in the Mazatzal Mountains, Arizona, on gray foxes ( Urocyon cinereoargenteus ) and coyotes ( Canis latrans ). We indexed relative abundance 3 times each year from 1996 to1998 using scat transects in burned and unburned areas. We collected scats to estimate diet and measured small mammal abundance and mast availability in 1997 and 1998. We also measured vegetation cover in burned and unburned sites. Gray fox indices declined 3 months postfire, but after 30 months, indices returned to preburn levels. Coyote indices did not change. Primary foods for both species in burned and unburned sites were mast (fruits of shrubs) and rodents, and diet comparisons between sites became similar as plant succession continued. Scat indices did not correlate with seasonal small mammal abundance. We suspect that the lower abundance indices of gray foxes were related to reduction in cover and food availability, because indices increased as vertical cover and mast crop increased. These data indicate that the effects of this catastrophic fire were short-term but also highlight the importance of preserving shrub and vegetation diversity for gray fox.     

Summer food habits of coyotes in central Wyoming

Summer food habits of coyotes ( Canis latrans ) were investigated on a 3100-km 2 area in central Wyoming, divided into one deer-use area and five non-deer areas. Analysis of 404 scats (fecal samples) revealed an overall average of 63 percent occurrence of native ungulates, 63 percent leporids, 46 percent rodents, 14 percent livestock, and 11 percent birds. Pronghorn ( Antilocapra Americana ) was the ungulate most frequently consumed, occurring in about 87 percent of the scats. Mule deer ( Odocoileus hemionus ) occurred in only 8 percent, and in 5 percent the native ungulate remains were not identifiable beyond order. This large percentage of big game in the diet is apparently unusual, because big game has been of minor importance in most coyote food-habit studies. The high incidence of leporids is consistent with other studies performed in arid intermountain areas. Although cricetines, especially deer mice ( Peromyscus maniculatus ), were trapped consistently in all habitats, months, and trapping areas, they were found in scats at a lower frequency than microtines and sciurids. This suggests a coyote hunting strategy that selected for the latter two groups.     

Seasonal variations in the time–activity budget of Royle’s pika in the Western Himalaya,India

ABSTRACT

The time–activity budget of a species has ecological relevance because natural selection often favours individuals that utilise their time most efficiently. Details of time–activity budgets can provide information on how animals allocate time to their various activities through the day and during different seasons to most efficiently cope with varying energy demands and environmental changes that may threaten their survival. Efficient use of time–activity budget is also crucial for alpine small mammals, which live in a highly seasonal environment with restricted periods in which to gain energy and successfully reproduce. Hence, variations in the time–activity budget of the high-elevation lagomorph Royle’s pika (Ochotona roylei) were analysed during different seasons over 2 years across an elevational gradient (2900–3680 m). Seven behavioural conditions were recorded in adult and juvenile pikas through daily focal sampling between 0600 and 1900 hrs. Royle’s pika had bimodal activity: animals were most active during the morning and early evening and relatively inactive during midday hours. Adult pikas allocated the largest proportion of their time–activity budget to foraging and the smallest proportion to vocalisation. Greater food availability during the monsoon season encouraged pikas to spend more of their time foraging than on other activities. In the autumn, pikas spent more time on locomotory and musing activities. Vigilance activities were most frequent during midday hours, possibly due to a high risk of predation. Locomotion and foraging were the predominant behaviours of juveniles during the summer and monsoon seasons. Prominent food hoarding activities were not observed in either adult or juvenile pikas. Information on time allocation to different activities during different seasons should provide a baseline for future behavioural ecology and bioenergetic analyses of pikas and help to understand their potential for adaptation to climate change.     

Haypiles of the mountain beaver ( Aplodontia rufa ) delay plant decomposition

Mountain beavers cache plants in neat piles above the ground near the entrances to their underground burrows, although the purpose of these hay piles remains controversial. We tested the hypothesis that drying plants in piles above ground may slow decay when the plants are stored underground. Predried plants and undried controls were placed in abandoned burrows. Plants that had been predried retained more green and decayed more slowly than undried controls. This experimental test supports the hypothesis that haying may extend the time during which plants are useful to mountain beavers.     

Gray Partridge foraging ecology in eastern South Dakota

We examined crop contents of 217 Gray Partridge ( Perdix perdix ) collected during a two-year period in eastern South Dakota. Row crop grains (corn, sunflowers) dominated late fall, winter, and spring diets. Small grains (oats, barley, wheat, rye) were rarely consumed although fields of small grains were widely available. During a severe winter when waste row crop grains were buried by snow, partridge consumed more leafy vegetation. Insects dominated the early summer diet, while foxtail ( Setaria spp.) seeds were a major late summer and early fall food.     

Winter habitats and foods of Blue Grouse in the Sheeprock Mountains, Utah

Winter habitat use and food habits of Blue Grouse ( Dendragapus obscurus ) were studied in an isolated Utah desert mountain range that contained little typical Douglas-fir ( Pseudotsuga menziesii ) winter habitat. Habitat use was concentrated in the Douglas-fir and pinyon ( Pinus edulis )-juniper ( Juniperus spp. ) habitat. Douglas-fir and pinyon pine were the most consumed foods. Other foods that represented >15% of the composition of an individual fecal sample were limber pine ( Pinus flexilis ), mahogany ( Cercocarpus ledifoliu ), juniper, and an Anteunaria-Cirsium type. The breadth in winter diet indicates that Blue Grouse may successfully occupy other habitats when typical winter habitat is scarce.     

Seasonal microhabitat relationships of blue grouse in southeastern Idaho

Microhabitat characteristics of blue grouse ( Dendragapus obscurus ) were analyzed in breeding and wintering habitats in southeastern Idaho. Breeding habitats typically were open sagebrush ( Artemisia spp.), mixed shrub, mountain mahogany ( Cercocarpus ledifolius ) , and maple ( Acer grandidentatum ) stands on east to south facing aspects of slopes below 2100 m elevation. Breeding blue grouse selected areas with approximately a 50:50 or greater open to cover ratio. Blue grouse selected areas with higher tree coverage than available on average within the mixed shrub vegetation type. Hens with broods preferred sites with relatively tall (>50 cm) herbaceous vegetation. During autumn and winter, blue grouse preferred high elevation (>2285 m) stands of open (50% tree cover) conifer. Douglas-fir ( Pseudotsuga menziesii ) were preferred as winter roost trees. Sites selected in winter had significantly more Douglas-fir than those selected in autumn.      

Diets of sympatric bobcats and coyotes during years of varying rainfall in central Arizona

We collected fecal samples (scats) of sympatric bobcats ( Lynx rufus ) and coyotes ( Canis latrans ) between 2000 and 2003 in a 53,600-ha area of the Upper Sonoran Desert in central Arizona. Our objective was to investigate composition, diversity, and overlap of diets of bobcats and coyotes in relation to varying rainfall in the Sonoran Desert of central Arizona. In general, bobcats ate more rodents than did coyotes, and coyotes ate more lagomorphs, large prey, and fruit/seeds than did bobcats. Composition of bobcat diets was independent of differences among years in annual rainfall and seasonal rainfall during summer–autumn (May–October) and winter–spring (November–April). Composition of coyote diets also was independent of drought conditions among years during summer–autumn, but coyotes ate more large prey and fewer rodents during years with winter–spring drought. Seasonally, bobcats ate more rodents than did coyotes in summer–autumn and winter–spring, whereas coyotes ate more lagomorphs than did bobcats during winter– spring, and more large prey and fruit/seeds in both seasons. Coyotes ate more large prey and lagomorphs during winter–spring, when seasonal rainfall was higher, and more fruit/seeds in summer–autumn, when seasonal rainfall was lower. Diversity of diets was consistently higher for coyotes than for bobcats, and increased for bobcats but not for coyotes during winter–spring drought and during higher seasonal rainfall in winter–spring. Overlap of diets between predators was independent of rainfall levels. We suggest that bobcats in the Sonoran Desert are more selective, specialized predators and that coyotes are more generalist, opportunistic predators. We hypothesize that, although diversity of bobcat food items and composition of coyote diets differ with varying rainfall in the Sonoran Desert, patterns of feeding strategy are independent of seasonal differences in precipitation and effects of drought, and bobcats and coyotes partition food resources independently of varying rainfall.     

Use of nonalpine anthropogenic habitats by American pikas ( Ochotona princeps ) in western Oregon

The American pika ( Ochotona princeps Richardson) has long been characterized in field guides and popular literature as an obligate inhabitant of alpine talus and as having relatively low dispersal capability. However, recent work reveals pikas to have broader habitat associations than previously reported. Over a large portion of the western slope of the Cascade Range in Oregon, pikas inhabit relatively low-elevation sites far from alpine areas and frequently occur in rocky man-made habitats such as roadcuts or rock quarries. We present observations of pikas in these previously overlooked habitats and discuss implications for (1) the proposed listing of the American pika as an endangered or threatened species; (2) furthering our understanding of pika population dynamics, habitat associations, and dispersal capabilites; and (3) management of federal, state, and private forest lands. Por mucho tiempo la pika americana ( Ochotona princeps Richardson) ha sido caracterizada en guías de campo y literatura popular como un habitante obligado de taludes alpinos y por tener una capacidad de dispersión relativamente baja. Sin embargo, trabajo reciente ha revelado que las pikas tienen asociaciones de hábitat más amplias de lo que hasta ahora se creía. En una gran parte de la vertiente occidental de la cordillera Cascade en Oregón, las pikas habitan sitios de elevación relativamente baja, lejos de las áreas alpinas y frecuentemente aparecen en hábitats rocosos artificiales tales como canteras y cortes de carretera. Presentamos observaciones de pikas en estos hábitats pasados por alto anteriormente y discutimos las implicaciones para (1) la propuesta de agregar la pika americana a la lista de especies amenazadas o en peligro; (2) ampliar nuestro conocimiento sobre la dinámica poblacional, las asociaciones de hábitat y la capacidad de dispersión; y (3) la gestión de tierras forestales federales, estatales y privadas.     

Fecal pellets of American pikas ( Ochotona princeps ) provide a crude chronometer for dating patch occupancy

American pikas ( Ochotona princeps ) seem to be especially vulnerable to climate change, with recent extinctions of pika populations being attributed to global warming. Incomplete historical location records are currently used to examine changes in pika distributions. A method of determining recent pika distributions in the absence of historical records is needed. Here I report on changes over time of known-age pika fecal pellets up to 36 years old. Predictable changes in diameter, internal consistency, and color of pellets provide a method to approximate the dates of last occupation in patches where pikas have been extirpated. La pika Americana ( Ochotona princeps ) parece ser especialmente vulnerable al cambio climático, al que se atribuyen extinciones recientes de sus poblaciones. Actualmente, se están utilizando los registros históricos incompletos de ubicación para examinar cambios en las distribuciones de pikas. Es necesario un método para determinar distribuciones recientes de pikas a falta de registros históricos. Reporto aquí los cambios que se han observado con el transcurso del tiempo en bolitas fecales de hasta 36 años de antigüedad. Cambios predecibles en diámetro, consistencia interna y color de las bolitas proporcionan un método para datar aproximadamente cuánto hace que vivían pikas en sitios de los que han sido extirpadas.     

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’ exposure to plague.     

Habitat and diet of Bhutan takin Budorcas taxicolor whitei during summer in Jigme Dorji National Park,Bhutan

Little is known about the ecology of the rare and vulnerable Bhutan takin Budorcas taxicolor whitei, a large and basically forest-dwelling goat-antelope inhabiting mountain valleys in northern Bhutan. In Tsharijathang valley (3800 m asl) in Jigme Dorji National Park, we described the summer habitat of this takin subspecies through vegetation transects and by studying diet via microhistological analysis of faeces supplemented by examination of feeding sites. The habitats utilized by the c.250 animals occupying the valley consisted of six main vegetation types with roughly equal coverages, viz. three forest types (dominated by Juniperus, Betula or Abies), alpine scrub (mainly low Rhododendron shrubs), open alpine meadow (mainly graminoids and forbs) and semi-open willow shrub (mainly Salix and forbs). Sixty-eight food species were identified in the feeding sites, but the bulk of the diet consisted of ≈10 species, the same species that also dominated the faecal material. With >50% of the diet consisting of shrubs, mainly Salix myrtillacea, the takins were mainly browsers. When foraging, they exhibited a weak form of selection by choosing sites with a slightly higher coverage of the most important food species and, while at these, proportionally more feeding signs were recorded. Domestic yak Bos grunniens are allowed to graze in the study area during winter when the takins have descended to lower elevation. At the present grazing pressure, the wintering yaks probably benefit the takin by maintaining the open vegetation structure, but their numbers and impact on the habitat should be monitored to prevent adverse effects.     

Habitat use and diet of the endemic lizard Ameivula nigrigula (Squamata: Teiidae) in Caatinga domain,Northeastern Brazil

ABSTRACT

The lizard Ameivula nigrigula is endemic to Caatinga vegetation and the transition zone between the Caatinga and Cerrado domains in Brazil. It was recently described, but little is known about its biology. We analysed microhabitat use and the diet of this species in Caatinga vegetation in Santo Inácio, Bahia State. Its diet consisted mainly of arthropods and plant material, and in particular aggregate (e.g. termites) and large preys (e.g. Coleoptera, insect larvae and spiders), reflecting their nutritional and energy values and high water contents. With regard to habitat use, we found A. nigrigula using microhabitats with tall vegetation over accumulated leaf litter, which could potentially contribute to temperature regulation. Together, those characteristics contribute to the survival of lizards in environments with low water availability and high temperatures, such as the Caatinga domain.     

Observations on the reproduction, sources of mortality, and diet of the Kendall Warm Spring dace

The life history of the endangered Kendall Warm Springs dace ( Rhinichthys osculus thermalis ) is largely unknown. Our study of its reproduction, sources of mortality, and diet indicated that Kendall Warm Springs dace seem to be reproductively active throughout the year, but the rate of reproduction appears to decrease during the winter. Males become sexually mature at 34 mm total length and females at 40 mm total length. We observed 2 sources of mortality: (1) emigration from the warm spring over a waterfall into the Green River and (2) predation on larvae by dragonfly ( Libellula saturata ) nymphs. Stomachs of Kendall Warm Springs dace contained small (≤ 1.5 mm total length) benthic invertebrates, primarily dipterans and mollusks.     

Summer food habits of coyotes in Idaho's River of No Return Wilderness Area

Summer food habits of coyotes ( Canis latrans )in the River of No Return Wilderness Area, Idaho, were determined. Analysis of 51 scats (fecal samples) revealed that Columbian ground squirrels ( Spermophilus columbianus ), mule deer ( Odocoileus hemionus ), and deer mice ( Peromyscus manniculatus ) exhibited the greatest frequency of occurrence for identified food items, being detected in 57%, 27%, and 16%, respectively, of scats examined.