First specimen records for Ruffed Grouse in Colorado

We report the first specimen records for Ruffed Grouse ( Bonasa umbellus ) collected in Colorado, provide the location, describe the habitat, and briefly discuss the rarity of this species within the state. Three Ruffed Grouse were collected, an adult male in September 1988 and a juvenile male and adult female in September 1990, on Hoy Mountain, Moffat County, Colorado, within 0.6 km of Utah. The habitat is primarily open Douglas-fir ( Pseudotsuga menziesii ) forest with scattered clumps of quaking aspen ( Populus tremuloides ) and Utah serviceberry ( Amelanchier utahensis ). Habitats to the north, east, and south are primarily dominated by sagebrush ( Artemisia spp.) steppe and pionjuniper ( Pinus spp.-- Juniperus spp.) woodland. We hypothesize that natural expansion of Ruffed Grouse further east, north, and south is prohibited by unsuitable habitat exacerbated by the limited flight range capability of the species.     

Ruffed grouse ( Bonasa umbellus ) foraging in aspen stands during winter in northern Utah

Ruffed Grouse ( Bonasa umbellus ) population densities are lower in the Intermountain West than elsewhere in the species' range. Throughout much of its range, the Ruffed Grouse is closely associated with quaking aspen ( Populus tremuloides ), in part because aspen buds are an important winter food. Because population fluctuations of Ruffed Grouse have been associated with changes in aspen abundance or chemical composition, we studied winter foraging of the species in the Intermountain West where it has received little attention. Aspen buds were the most prominent forage in the bird's diet, although in contrast to other Ruffed Grouse food habits studies, reproductive buds were not eaten more than vegetative buds, and buds of other deciduous plants were also important (>20% of the diet). Excretion of high concentrations of ammonium nitrogen suggests that grouse in northern Utah are ingesting higher levels of secondary plant compounds than reported elsewhere. Our results show aspen is important in the winter ecology of Ruffed Grouse in northern Utah and suggest that continued loss of aspen may impact grouse populations.     

Fire frequency and the vegetative mosaic of a spruce-fir forest in northern Utah

Fire scar and vegetative analysis were used to construct a fire history for the Engelmann spruce/subalpine fir ( Picea engelmannii/Abies lasciocarpa ) vegetation type of Utah State University (USU) T. W. Daniel Experimental Forest. Three distinct periods of fire frequency were established-presettlement (1700-1855), settlement (1856-1909), and suppression (1910-1990). Mean fire interval (MFI) decreased during the settlement period and greatly increased during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of nearby Cache Valley, located 40 km to the west. Logging and livestock grazing appear to have led to the reduced MFI, which in turn worked as a factor to create the vegetative mosaic now observed on the study area. The increase in MFI during the suppression ear permitted the advancement of shade-tolerant species in the understory of the shade-intolerant lodgepole pine ( Pinus contorta var. latifolia ) and quaking aspen ( Populus tremuloides ). Continued suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experience the lowest MFI during the settlement period, to be further invaded by shade-intolerant species, decreasing spatial stand diversity and increasing the risk of more intense fires.     

Yellow pine chipmunks cannot climb quaking aspens: implications for avian nest site selection

Predation of eggs or nestlings is generally believed to be the most influential factor limiting passerine reproductive success. Thus, there should be strong selective pressures for birds to place their nests in sites that are inaccessible to predators or that are less likely to be discovered by them. We found and monitored 231 nests of 4 species of arboreal, cup-nesting birds: Western Wood-Pewee ( Contopus sordidulus ), Warbling Vireo ( Vireo gilvus ), American Robin ( Turdus migratorius ), and Yellow-rumped Warbler ( Dendroica coronata ). We determined strength of nest tree species selection by comparing nest trees and tree species availability. Western Wood-Pewees and Warbling Vireos demonstrated strong preference for placing nests in quaking aspen ( Populus tremuloides ). Yellow-rumped Warblers showed a weak preference for aspen, and American Robins demonstrated no preference. We designed a series of experiments to determine whether yellow pine chipmunks ( Tamias amoenus ), an abundant nest predator, could climb aspen trees and, if so, what factors might prevent them from doing so. Yellow pine chipmunks were unable to climb aspen but showed no difficulty in climbing and maneuvering on lodgepole pine ( Pinus contorta ) boles, which were identical in diameter to aspen boles. Refuge from chipmunks as potential nest predators is likely contributing to nest site selection for a few arboreal cup-nesting bird species where aspen trees are available.     

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.     

Physical characteristics of Blue Grouse winter use-trees and roost sites

Physical characteristics of winter use-trees and roost sites of Blue Grouse ( Dendragapus obscurus ) were studied in northeastern Utah. Blue Grouse selectively roosted in the largest Douglas-fir ( Pseudotsuga menziesii ) trees during the day and subalpine fir ( Abies lasiocarpa ) trees at night. Diurnal and nocturnal roosts were typically adjacent to tree trunks in the lower two-thirds of trees. Nocturnal roosts provided greater canopy and denser shelter than diurnal roosts. Roost site selection was consistent with occupation of favorable microhabitat, particularly at night, and foraging strategy during the day. Timber management strategies should perpetuate large trees within Douglas-fir-subalpine fir habitat in areas occupied by wintering Blue Grouse.     

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.     

Nesting and summer habitat use by translocated Sage Grouse ( Centrocercus Urophasianus ) in central Idaho

We translocated 196 Sage Grouse ( Centrocercus urophasianus into Sawtooth Valley, Idaho, during March-April 1986-87 to augment a small resident population. Forty-four grouse equipped with radio transmitters were monitored through spring and summer. Nest sites ( n = 6) had greater ( P = .032) horizontal cover than did independent random plots ( n = 7). During summer, grouse used sites ( n = 50) with taller live and dead shrub heights, greater shrub canopy cover, and more ground litter ( P n = 50) 50-300 m from use sites. Distance to edge and mountain sagebrush ( Artemisia tridentata vaseyana ) density best separated use sites from independent random plots in logistic regression analysis and correctly classified 64% of the use sites and 78% of the independent random plots. Sage Grouse used sties that had narrower frequency distributions for many variables than did independent plots ( P < .04), suggesting selection for uniform habitat.     

Some aspects of succession in the spruce-fir forest zone of northern Utah

A site in the Rocky Mountain subalpine forest zone with which a series of hypotheses concerning ecosystem succession was tested is characterized. Succession from herb-dominated meadows to climax forests of Engelmann spruce and subalpine fir can follow at least four identified pathways. After fire, spruce and fir may reinvade a site directly, follow invasion by aspen, or follow invasion by lodgepole pine, the pathway depending on a combination of physical and biotic factors. In other cases, succession begins with long-established meadows which do not owe their existence to fire. In this latter pathway, aspen invades meadows by suckering and changes the environment near the soil surface so as to facilitate establishment of the climax tree species. The biota and soils of four characteristic seral stages (meadow, aspen, fir, spruce-fir) in this latter pathway are described.     

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.     

Blue Grouse nesting parameters and habitat associations in northeastern Oregon

We examined Blue Grouse ( Dendragapus obscurus ) nesting characteristics in northeastern Oregon to identify relationships between hen age and nesting parameters and to ascertain habitat charactersicts related to successful nests. Adult and yearling hens exhibited no differences in clutch size, percentage of eggs hatched, nesting success, or hatch dates. Among nests located under logs, 100% ( n =10) hatched ≥ 1 egg, whereas 58% ( n = 10) of 17 nests not under logs hatched ≥ 1 egg.     

Use and selection of brood-rearing habitat by Sage Grouse in south central Washington

Sage Grouse ( Centrocercus urophasianus ) brood-habitat use was examined during 1992 and 1993 at the Yakima Training Center in Yakima and Kittitas counties, Washington. During the 2 yr we followed 30 broods, of which 12 persisted to 1 August (￣ x = approximately 1.5 chicks/brood). Food forb cover was greater at all brood locations than at random locations. Hens with broods in big sagebrush/bunchgrass habitat ( Artemisia tridentata/Agropyron spicatum ) selected for greater food forb cover, total forb cover, and lower shrub heights; broods in altered big sagebrush/bunchgrass habitats selected greater tall grass cover and vertical cover height; broods in grassland showed no preference for any measured vegetation characteristics. During the early rearing period (post-hatching-6 wk) each year, broods selected sagebrush/bunchgrass. Broods in 1993 made greater use of grasslands than in 1992 and selected grassland during the late brood-rearing period (7-12 wk). Broods selected for sagebrush/bunchgrass during the midday, but 52% of brood locations in the afternoon were in grassland. Tall grass cover was greater at morning (0500-1000 h) and afternoon (1501-2000 h) brood locations than at midday (1001-1500 h) and random locations. Midday brood locations had greater shrub cover and height than morning and afternoon locations. Selection of habitat components was similar to the results of other studies, but habitat conditions coupled with a possible lack of alternate brood-rearing cover types resulted in low survival of chicks.     

Ecology of Comandra umbellata (Santalaceae) in western Wyoming

Comandra umbellate is the alternate host of a hard pine canker rust disease induced by the fungus Cronartium comandrae . The occurrence and density of C. umbellata were recorded near lodgepole pine stands in the Wind River District, Shoshone National Forest, Wyoming. Comandra populations occurred most often on slopes with southern aspects, particularly southwestern, and on steep slopes; these sites tended to be dry and relatively open. Comandra was also found growing under heavy perennial shrub canopy covers. It was most often associated with sagebrush but was common near other perennial shrubs as well. Overall, C. umbellata appeared to be a poor competitor with dense grass populations. Comandra was found primarily on Abies lasiocarpa/Juniperus communis, Pinusflexilis/ Hesperochloa kingii , and Artemisia tridentata/Festuca idahoensis habitats. No comandra was found in the Abies lasiocarpa/Vaccinium scoporium habitat.     

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.     

Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon

The chronology of Juniperus occidentalis (western juniper) expansion in eastern Oregon, the effect of plant canopy and interspace on J. occidentalis seedling establishment and growth rates, and the age of J. occidentalis maximum reproductive potential were determined. Measurements were recorded in twenty-two 0.4-ha plots established in sagebrush-grassland communities and six 0.1-ha plots in Populus tremuloides (quaking aspen) communities. J. occidentalis began increasing during the 1880s in stands containing > 130 yr old. Relatively steady establishment ensued into the 1950s and then began to progress at a geometric rate in the 19602. J. occidentalis encroachment into aspen stands began between 1910 and 1920. The largest proportion of juvenile trees established beneath Artemisia species in sagebrush-grassland communities. J. occidentalis trees appeared to reach full reproductive potential at > 50 yr of age. The ratio of male:female trees increased from 1.7 in scattered J. occidentalis stands to 3.8 in closed stands. The initiation of J. occidentalis encroachment during the late 1800s coincides with optimal climatic conditions for Juniperus berry production and establishment, reduced fire-return intervals, and heavy livestock grazing. The accelerated increase in J. occidentalis expansion since 1960 may be due to the continued absence of fire, abundant woody plant cover, and the large increase in J. occidentalis seed production.     

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.     

Vegetal responses and big game values after thinning regenerating lodgepole pine

Understory vegetal response was found to significantly increase with the degree of thinning in an early regenerating, dense stand of lodgepole pine ( Pinus contorta ). The value of the increased vegetation for deer and elk was determined to be important through comparisons with known dietary and habitat preferences.     

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.