Treesearch

We studied habitat use by Mountain Quail (Oreortyx pictus) at four sites in northern California. Vegetative cover types (macrohabitats) were used in proportion to availability. Significant microhabitat variables which distinguished used from available microhabitat structure included proximity to water and tall, dense shrubs. Mountain Quail population densities ranged from 9 to 30 birds per 100 ha; populations with greater densities used a larger range of the available microhabitat structure.

Avian use of scoria outcrop habitats was compared to use of sagebrush (Artemisia spp.)/grassland habitats. Outcrop habitats exhibited higher species richness, total population density, density of lark sparrows (Chondestres grammucus), and density of rock wrens (Salpinctes obsoetus). Western meadowlarks (Sturnella neglecta) and vesper sparrows (Pooecetes grumineus) were more abundant in sagebrush/grassland habitats than in scoria outcrops. Habitat relationship models indicated that the unique plant community and structural diversity provided by the scoria outcrops were correlated with...

Home range size and habitat utilization of three breeding male Richardson’s Merlins (Falco columbarius richardsonii) in southeastern Montana were studied using radio telemetry. Home ranges of these birds encompassed 13,23, and 28 km2. Each bird traveled up to 9 km from its nest. Each home range encompassed five habitats; sagebrush/grassland, riparian, and Ponderosa Pine (Pinus ponderosa) communities were used significantly (p < 0.05) more, and grasslands and agricultural fields less (p < 0.05), than expected, based on the proportions in the combined home ranges. Four sites regularly used...

Eggshell weight and thickness indices of Richardson’s Merlin (Falco columbarius richardsonii) eggs collected in southeastern Montana were significantly (p < 0.01) lower than pre-1946 samples. Montana eggshells showed reductions of 13% in shell weight and 20% in shell thickness indices when compared to eggshells collected before 1946. The decreased eggshell weights and thickness indices and the occurrence of 7 organochlorine compounds in Merlin eggs recently collected in southeastern Montana indicates that this raptor population merits periodic monitoring.

Twenty-six hybrid poplar clones were planted as cuttings on a gold mine tailings in the Black Hills. Four exhibited very good survival and growth. Other clones had relatively high (exceeding 50 percent) survival but slow growth (below 60 cm) over a 5-year period.

We studied the effects of observer variability when estimating vegetation characteristics at 75 0.04-ha bird plots. Observer estimates were significantly different for 31 of 49 variables. Multivariate analyses showed significant interobserver differences for five of the seven classes of variables studied. Variable classes included the height, number, and diameter of trees, height to the first live tree branch, height and number of shrubs, and composite variables. We then compared observer estimates with measurements of the same habitat variables. Univariate and multivariate comparisons of...

Browse utilization estimates based on twig length and twig weight were compared for skunkbush sumac, wax currant, and chokecherry. Linear regression analysis was valid for twig length data; twig weight equations are nonlinear. Estimates of twig weight are more accurate. Problems encountered during development of a utilization model are discussed.

Literature pertaining to woodlands of southwestern North Dakota is reviewed. Woodland species composition and distribution, and factors influencing woodland ecosystems such as climate, logging, fire, and grazing are described. Potential management and improvement techniques using vegetation and livestock manipulation have been suggested.

Conifer establishment following regeneration treatments can be predicted in the grand fir-cedar-hemlock ecosystem of the northern Rocky Mountains. Alternative treatments can be evaluated by a model that represents regeneration establishment and early development. This model is designed to be used with the Intermountain Forest and Range Experiment Station's Prognosis Model (Stage 1973). Mathematical equations representing most harvest and site preparation methods common in the northern Rocky Mountains predict the probability of stocking, trees per acre, species composition, and tree heights...

Guidelines are provided to help forest managers and silviculturists develop even- and/or uneven-aged cutting practices needed to convert old-growth and mixed ponderosa pine forests in the Front Range into managed stands for a variety of resource needs. Guidelines consider stand conditions, and insect and disease susceptibility. Cutting practices are designed to integrate maintained water quality, improved wildlife habitat, and enhanced opportunities for recreation and scenic viewing, with providing wood products.