Brood habitat use by Sage Grouse in Oregon

Habitat use by Sage Grouse ( Centrocercus urophasianus hens with broods was examined at Jackass Creek and Hart Mountain, Oregon, from 1989 through 1991. Sage Grouse hens initially selected low sagebrush ( Artemisia spp.) cover types during early brood-rearing, big sagebrush cover types later in the brood-rearing period, and ultimately concentrated use in and near lakebeds and meadows. Areas used by Sage Grouse broods typically had greater forb frequency than did random sites. Hens at Jackass Creek selected sites with forb cover similar to that generally available at Hart Mountain, but home ranges were larger at Jackass Creek because of lower availability of suitable brood-rearing habitat. Differences in habitat use by broods on the two areas were reflected in dietary differences; at Hart Mountain, chicks primarily ate forbs and insects, whereas at Jackass Creek most of the diet was sagebrush. Larger home ranges, differences in diets, and differences in availability of forb-rich habitats possibly were related to differences in abundance and productivity between areas.     

Nesting and brood-rearing characteristics of Chukars in west central Idaho

We analyzed attributes from 23 nests (10 renests) and 46 brood locations of radio-marked Chukars ( Alectoris chukar ) in the lower Salmon River canyon of west central Idaho in 1995 and 1996. Nesting effort was 100%, apparent nest success was 45%, and estimated time from destruction or abandonment of a nest to initiation of laying a subsequent nest averaged 13 ± 5 days s x . Average clutch size for 1st nests (14.5 ± 1.0) was greater ( P = 0.017) than renests (10.4 ± 1.1). Cover types used by nesting Chukars included grass/forb (48% of nests), rock (43%), and shrub (9%), whereas the most common structure used for nests was rock outcrop (57%). Chukars did not use yellow starthistle ( Centaurea solstitialis ) habitats differently from what was expected ( P = 0.08) for nesting, but birds with broods selected areas with less starthistle ( P < 0.001). Chukar broods, which averaged 12.0 ± 1.1 chicks, used shrub and grass/forb cover types approximately equally (43% and 47% of locations, respectively) but rock habitats infrequently (11%).     

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.     

Summer habitat use and selection by female Sage Grouse ( Centrocercus urophasianus ) in Oregon

Cover types and vegetative characteristics (e.g., grasses, forbs, shrubs) used by female Sage Grouse ( Centrocercus urophasianus ) during summer were compared with available habitat on two study areas in southeastern Oregon. Broodless hens, which constituted 114 of the 125 (91%) radio-marked hens studied, selected big ( Artemisia tridentata ) subspp.) and low sagebrush ( A. arbuscular ) cover types at both study areas. At Hart Mountain, broodless hens did not select specific vegetative characteristics within cover types. However, at Jackass Creek, forb cover was greater ( P = .004) at broodless hen sites than at random locations. Differences in habitat use by broodless hens between study areas were associated with differences in forb availability. Broodless hens used a greater diversity of cover types than hens with broods. Broodless hens gathered in flocks and remained separate from but near hens with broods during early summer. By early July broodless hens moved to meadows while hens with broods remained in upland habitats.     

Brood-rearing habitat use by Rio Grande Wild Turkeys in Oregon

Wild turkey ( Meleagris gallopavo ) brood-rearing sites have been described for portions of their range, but brood-rearing habitat use and characteristics of brood-rearing sites used by Rio Grande Wild Turkeys ( M. g. intermedia ) in the Pacific Northwest were unknown. We described cover types at 362 brood-rearing sites and measured habitat characteristics at 64 of these sites used by a recently established Rio Grande Wild Turkey population in southwestern Oregon during May-September 1989 and 1990. Hens with broods used 9 of 10 available cover types. Meadows, mixed hardwood/conifer woodlands, and savannas were used more often than expected (47% of observations, P ≤ 0.05). Broods used mature mixed conifer and dense sapling/pole mixed conifer cover types less than expected and did not use brush-fields. Many brood-rearing sites were characterized by a parklike appearance. Understory vegetation averaged P ≤ 0.05). We suggest that land managers maintain mixed hardwood/conifer woodland and savanna cover types adjacent to meadows on south slopes to provide brood-rearing habitat for Rio Grande Wild Turkeys in southwestern Oregon.     

Suitability of shrub establishment on Wyoming mined lands reclaimed for wildlife habitat

Restoring coal mined land to pre-mining shrub cover, density, height, community composition, and diversity to renew wildlife habitat quality is a priority for reclamation specialists. Long-term shrub reestablishment success on reclaimed mined land in Wyoming and suitability of these lands for wildlife habitat are unknown. Fourteen reclaimed study sites, 10 yr old or older, were selected on 8 mines in Wyoming to evaluate shrub reestablishment and wildlife habitat value for antelope ( Antilocapra americana ) and sage grouse ( Centrocercus urophasianus ). Five sites were categorized as fourwing saltbush ( Atriplex canescens ) sites and 9 as fourwing saltbush/big sagebrush ( A. canescens/Artemisia tridentata spp. wyomingensis ) sites. Published data describing antelope and sage grouse-preferred habitat requirements in sagebrush-grassland steppe ecosystems were used to evaluate shrub community value of sampled sites for wildlife habitat. Mean shrub canopy cover, density, and height for fourwing saltbush sites were 5.8%, 0.23 m -2 , and 41.6 cm, respectively, compared to 5.6%, 0.61 m -2 , and 31.1 cm for fourwing saltbush/big sagebrush sites. Two fourwing saltbush and 4 fourwing saltbush/big sagebrush sites provided sufficient cover for antelope, while 2 fourwing saltbush and 4 fourwing saltbush/big sagebrush sites were adequate for sage grouse. Only 1 fourwing saltbush/big sagebrush site provided high enough shrub densities for sage grouse. One fourwing saltbush and 7 fourwing saltbush/big sagebrush sites provided ample shrub heights for antelope, while 1 fourwing saltbush and 8 fourwing saltbush/big sagebrush sites were sufficient for sage grouse. One fourwing saltbush and 1 fourwing saltbush/big sagebrush site provided enough grass, forb, and shrub composition for antelope, while no site in either reclamation type was satisfactory for sage grouse. Shrub diversity was 3 times higher for fourwing saltbush/big sagebrush sites (0.984) than for fourwing saltbush sites (0.328). Individually, sites seeded with multiple shrub species had higher canopy cover, density, and diversity compared with single-species shrub seedings. Achieving premining shrub cover, density, height, community composition, and diversity within existing bond-release time frames is unrealistic, considering that some native shrublands require 30-60 yr to reach maturity.     

Predation of artificial Sage Grouse nests in treated and untreated sagebrush

We measured predation on 120 artificial Sage Grouse ( Centrarcus urophasianus ) nests in montane sagebrush grassland in northern Utah. We examined nests in areas that had been chained and seeded 25 years previously (treated areas) and in areas that were untreated. Predation rates of artificial nests were higher in areas of untreated sagebrush, even though these areas had greater sagebrush cover, taller shrubs, and greater horizontal plant cover. These results differ from those previously hypothesized for treated sagebrush habitat and may reflect a greater abundance of other potential prey species, especially lagomorphs, in untreated areas that attracted greater densities of predators. In addition, over 80% of nests were depredated by mammals, which hunt using olfaction and are less likely than avian predators to be affected by nest cover. We conclude that, after treated sagebrush has recovered to some degree, predation rates of Sage Grouse nests may be lower in treated sagebrush. Consequently, factors other than nest predation (e.g., winter food, thermal cover, insects, perennial forb abundance) may be more important reasons for preserving mature sagebrush stands for Sage Grouse.     

Summer habitat use by Columbian Sharp-tailed Grouse in western Idaho

We studied summer habitat use by Columbian Sharp-tailed Grouse ( Tympanuchus phasianellus columbianus ) in western Idaho during 1983-85. Vegetative and topographic measurements were recorded at 716 locations of 15 radio-tagged grouse and at 180 random sites within the major vegetation/cover types in the study area. The mean size of summer home ranges was 1.87 ± 1.14 km 2 . Of eight cover types identified in the study area, individual grouse used the big sagebrush Artemisia tridentata ) cover type more than or in proportion to availability, the low sagebrush ( A. arbuscula ) in proportion to availability, and avoided the shrubby eriogonum ( Eriogonum spp.) type. Characteristics of the big sagebrush cover type that Sharp-tailed Grouse preferred include moderate vegetative cover, high plant species diversity, and high structural diversity. Grouse used areas of dense cover (i.e., mountain shrub and riparian cover types) primarily for escape cover. Compared with random sites, grouse selected areas with (1) greater horizontal and vertical cover, (2) greater canopy coverage of forbs typically decreased by livestock grazing, (3) greater density and canopy coverage of arrowleaf balsamroot ( Balsamorhiza sagittata ), and (4) greater canopy coverage of bluebunch wheatgrass ( Agropyron spicatum ) in the big sagebrush cover type in 1984 and the low sagebrush cover type in 1985. The importance of the native perennials arrowleaf balsamroot and bluebunch wheatgrass became apparent during a drought year when many exotic annuals dried up and provided no cover. Overall, grouse selected vegetative communities that were least modified by livestock grazing.     

Behavior and habitat preferences of ring-necked pheasants during late winter in central Utah

Ring-necked pheasant behavior and habitat preferences were studied during late February along benches of the Wasatch Mountains in central Utah. Seven behavioral categories were used to classify pheasant activities during three time periods of the day. Eating, alert, and movement behavior were the most frequent activities during all periods of the day. Significant differences (p < .01) were found between morning and midday behavior and between midday and evening behavior. Pheasants fed in open areas during morning hours then retreated into heavy cover during midday periods. The birds remained in heavy cover until late afternoon. Pheasants then moved away from heavy cover into semiopen areas to feed as evening approached.     

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.&nbsp;     

Understory vegetation in fully stocked pinyon-juniper stands

Ten fully stocked pinyon-juniper stands contained a total of 73 species in the understory, but the number of understory species in any one stand was moderately low (mean = 20). On each stand, species of at least five different plant groups were present in the understory (shrub, perennial grass, perennial forb, annual grass, or annual forb). A perennial grass, Sandberg bluegrass ( Poa sandbergii ), and a group of annual forbs with relatively high cover and constancy among stands appeared best adapted to coexist with the pinyon-juniper overstory. The proportion of total plant cover was greater on tree-associated microsites (duff and transition) than in the interspace between trees because of the greater surface area of the former in most stands. The transition microsite was the most favorable for understory species and provided understory cover in disproportionately greater amounts than the area it occupied.     

A habitat suitability model for pygmy rabbits ( Brachylagus iIdahoensis ) in southeastern Idaho

A habitat suitability model was developed for pygmy rabbit ( Brachylagus idahoensis ) habitat on the Idaho National Engineering and Environmental Laboratory (INEEL) in southeastern Idaho. Suitable pygmy rabbit areas were characterized by greater cover and density of total shrubs and big sagebrush ( Artemisia tridentata ), as well as greater forb cover. Soil texture also played an important role in distinguishing suitable pygmy rabbit areas from nonuse sites. Principal components analysis (PCA) of several vegetation variables and soil texture was used to develop a habitat suitability model for pygmy rabbit habitat. This model, which can be used to successfully distinguish between pygmy rabbit use and nonuse areas on the INEEL, has the potential for use throughout the pygmy rabbits range.     

Habitat use patterns within the home range of pygmy rabbits ( Brachylagus idahoensis ) in southeastern Idaho

Pygmy rabbits ( Brachylagus idahoensis ) are a small sagebrush ( Artemisia tridentata ) obligate lagomorph found within the Great Basin of northwestern United States. Because of its reliance on sagebrush, this species is thought to be experiencing a major range reduction as a result of loss of sagebrush habitat. To aid in conservation of this species, we need to better understand its use of the sagebrush environment. We estimated summer home range use patterns by relocating 5 radio-collared pygmy rabbits (3 females and 2 males) over a 24-hour cycle. We then compared soil texture, shrub density, height, and canopy cover between areas close to burrow entrances and areas of high use and low use. Mean home range sizes of female and male rabbits were 37.2 and 67.9 ha, respectively. Rabbits had disproportionate amounts of time (68.4% ± 9.1, s￣x ) and travel (63.0% ± 5.7, s￣x ) in areas within a 60-m radius of their burrows. Soil texture did not differ among the 3 areas, but shrub density, specifically big sagebrush, and forb density were significantly higher close to the burrow than in the high- and low-use areas. We conclude that pygmy rabbits are possibly burrow obligates and that their abundance and distribution are likely limited by available burrow sites.     

Habitat characteristics of small mammals in southeastern Utah

We describe habitat characteristics of 8 small mammal species occurring in the Manti-LaSal National Forest in southeastern Utah. Thirty-seven grids across 7 vegetation types were sample by live-trapping from May through October 1994 and 1995. Logistic regression models of habitat measurements correctly classified small mammal presence 36%-87% of the time. Except for 1 instance, 4 Peromyscus species present in a specific vegetation type were negatively associated with forb or grass cover. Microtus montanus was present primarily on mesas and was positively associated with tall tree and low shrub cover. Neotoma mexicana was present only in canyons and was found primarily in the pinyon-juniper ( Pinus edulis-Juniperus osteosperma ) vegetation type. Tamias spp. was present in all vegetation types. Our results allow better management of these species by providing greater understanding of their use of habitat within vegetation types.     

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.     

Species diversity and habitat complexity: does vegetation organize vertebrate communites in the Great Basin?

In this study, we have examined the effect of vegetation structure on the three major vertebrate taxa in Great Basin habitats of southwestern Utah. The effect of increasing vegetation heterogeneity, both horizontally and vertically, on the diversities of lizards, rodents, and postbreeding birds was investigated. We found no statistically significant relationship between diversity of all animal taxa and horizontal vegetation heterogeneity, although lizard diversity tended to decrease with increasing heterogeneity and rodent diversity tended to increase. Bird species diversity was positively correlated with vertical habitat heterogeneity. Abundances were highest for rodents in pinyon/juniper habitat and highest for lizards and birds in areas with the highest grass cover. Species richness was highest in sagebrush habitat for rodents but highest for lizards and birds in pinyon/juniper. Evenness values were relatively similar and high for birds and rodents and were relatively high for lizards in all habitats except for pinyon/juniper, which had an evenness value of 0.38. For rodents and lizards, abundance was significantly correlated with the index for horizontal habitat heterogeneity. After logarithmic transformation, abundance of lizards was positively correlated with increasing vegetation complexity. Combined abundance of lizards and rodents was also positively correlated with vegetation complexity. Rodent and lizard abundances, however, were affected by different aspects of the habitat. After logarithmic transformation, lizard abundances increased significantly with increasing grass cover, whereas rodent abundances increased significantly with increasing shrub cover.     

Comparative habitat use in a juniper woodland bird community

We compared vegetation structure used by 14 bird species during the 1998 and 1999 breeding seasons to determine what habitat features best accounted for habitat division and community organization in Utah juniper ( Juniperus osteosperma ) woodlands of southwestern Wyoming. Habitat use was quantified by measuring 24 habitat variables in 461 bird-centered quadrats, each 0.04 ha in size. Using discriminant function analysis, we differentiated between habitat used by 14 bird species along 3 habitat dimensions: (1) variation in shrub cover, overstory juniper cover, mature tree density, understory height, and decadent tree density; (2) a gradient composed of elevation and forb cover; and (3) variation in grass cover, tree height, seedling/sapling cover, and bare ground/rock cover. Of 14 species considered, 9 exhibited substantial habitat partitioning: Mourning Dove ( Zenaida macroura ), Bewick's Wren ( Thryomanes bewickii ), Blue-gray Gnatcatcher ( Polioptila caerulea ), Mountain Bluebird ( Sialia currucoides ), Plumbeous Vireo ( Vireo plumbeus ), Green-tailed Towhee ( Pipilo chlorurus ), Brewer's Sparrow ( Spizella breweri ), Dark-eyed Junco ( Junco hyemalis ), and Cassin's Finch ( Carpodacus cassinii ). Our results indicate juniper bird communities of southwestern Wyoming are organized along a 3-dimensional habitat gradient composed of woodland maturity, elevation, and juniper recruitment. Because juniper birds partition habitat along successional and altitudinal gradients, indiscriminate woodland clearing as well as continued fire suppression will alter species composition. Restoration efforts should ensure that all successional stages of juniper woodland are present on the landscape.     

Habitat of three rare species of small mammals in juniper woodlands of southwestern Wyoming

Southwestern Wyoming constitutes the northern limit of the ranges of the cliff chipmunk ( Tamias dorsalis ), pinyon mouse ( Peromyscus truei ), and canyon mouse ( P. crinitus ). In addition to trying to determine their presence in the region, we wanted to identify habitat characteristics commonly used by each of these species. We used Sherman live-traps to sample 14 sites representing 2 distinct habitat types in 1998 and 1999: juniper-rocky slopes and juniper cliffs. Seventeen habitat characteristics were measured at capture locations for each species and compared with randomly located points. Best subsets multiple logistic regression was used to construct models that distinguish between used and available habitat for each species. The cliff chipmunk occurred in both rocky slopes and cliffs. The pinyon mouse was also captured in rocky slopes and cliffs and was most often captured in locations in the interior of the juniper woodland with high tree canopy cover, high forb cover, and low density of rock outcrops. The canyon mouse was captured only in cliffs at sites consisting of high forb cover, high rock cover, and high tree density.