Treesearch

Your first encounter with goshawks (Accipter gentilis) often leaves an impression that lasts a lifetime, especially if it involves being attacked by an angry female as you approach too close to her nest. I still clearly remember my first encounter when, as a 7th grader, I was invited to the field by two falconers who were hunting a brace of goshawks (i.e., two birds hunting simultaneously) in the scrub oak­covered foothills just west of Denver, Colorado. Both birds sprang from the falconer's fist as a cottontail rabbit (Sylvilagus nuttallii) darted through the scrub oak. The inexperienced...

We document the first observed instance of polygyny in Flammulated Owls (Otus flammeolus) and the first among insectivorous raptors. Chronologies of the male's two nests, which were 510 m apart, were separated by nearly 2 weeks. Each brood initially consisted of three owlets, similar to the mean brood size in monogamous pairs. The male delivered considerably fewer prey to the secondary nest, compared with prey-delivery rates at nests of monogamous males during the nestling period. Evidence suggested that all owlets fledged from the primary brood, but only one fledged from the secondary...

The identification of species from hair samples is probably as old as humanity, but did not receive much scientific attention until efficient and relatively inexpensive methods for amplifying DNA became available. Prior to this time, keys were used to identify species through the microscopic analysis of hair shaft morphology (Moore et al. 1974; also see Raphael 1994 for a review of pre-DNA approaches to species identification). For North American carnivores, such analyses are reliable primarily at the family level. Canid hairs, for example, can consistently be differentiated from felid...

Ponderosa pine (Pinus ponderosa) forests with Gambel oak (Quercus gambelii) are associated with higher bird abundance and diversity than are ponderosa pine forests lacking Gambel oak. Little is known, however, about specific structural characteristics of Gambel oak trees, clumps, and stands that may be important to birds in ponderosa pine-Gambel oak (hereafter pine-oak) forests. We examined associations among breeding birds and structural characteristics of Gambel oak at a scale similar in size to individual bird territories in pine-oak forests in northern Arizona and western New Mexico,...

The U.S. Forest Service and other federal agencies treated more than 2.8 million ha of forested land between 2001 and 2003 under the Healthy Forest Restoration Act (USDA Forest Service 2004). Because many more areas across our landscape are slated for fuel reduction treatments, understanding how wildlife communities will respond is essential to conserving biodiversity, yet little is understood about the ecological consequences of such treatments.

We assessed responses of the breeding bird community to mechanical thinning and prescribed surface fire, alone and in combination, between 2000 and 2006 in ponderosa pine (Pinus ponderosa) forests in northern Arizona, USA. Fuel-reduction treatments did not affect species richness or evenness, and effects on density of 5 commonly detected species varied among species. Populations of some species, such as the western bluebird (Sialia mexicana), increased following burning treatments, whereas others, such as the mountain chickadee (Poecile gambeli), decreased in response to thinning treatments...

Hybridization between federally threatened Canada lynx (Lynx canadensis) and bobcat (L. rufus) was recently documented in the United States, but little is known regarding physical characteristics of hybrids compared to parent species. We report on the morphology and physical characteristics of five of seven Canada lynx-bobcat hybrids detected near the southern extent of the lynx's geographic range in Maine, Minnesota and New Brunswick. Hybrids displayed a range of physical characteristics, including features common to both lynx and bobcat, or that were intermediate in character. Observation...

Many studies have investigated the ecological effects of roads and roadsides as both habitat and dispersal corridors for exotic plant species. Several of these compared roadside exotic species richness and abundance with adjacent interior habitats, but we found no studies of individual exotic species' abundance between the two habitats in the context of prescribed fire. We measured exotic species richness and individual species' abundance along roadsides and in adjacent interior habitat (.150 m) before and after prescribed fire at three ponderosa pine (Pinus ponderosa Douglas ex Lawson &...

Unique haplotypes indicating the presence of a residual native population of fisher were found in central Idaho (Vinkey et al. 2006). Fishers had been detected previously using camera sets in the Selkirk Mountains just south of the Canadian border, but their population status and genetic composition were unknown. The purpose of the study was to provide a comprehensive survey of the northern Selkirk Mountains and to determine the genetic makeup (and therefore population source) of detected fishers.

The Northern Goshawk (Accipiter gentilis) is a large, highly mobile, mostly nonmigratory and widespread forest raptor. It ranges across the Boreal forests from Alaska to Newfoundland, and south into forests of the Great Lakes, and montane regions of the Appalachian, Cascade, Sierra Nevada, Rocky Mountain, and Sierra Madre Occidental.