Treesearch

Previous chapters outlined the biology and ecology of boreal owls as well as the ecology of important vegetation communities based on literature from North America and Europe. That technical review provides the basis to assess the current conservation status of boreal owls in the United States. By conservation status, we mean the demographic condition of the species as it relates to the likelihood of local and national persistence of wild populations over the long term. Are populations of boreal owls in the United States currently threatened? Are current land management practices likely to...

Most humans are reluctant to make decisions without thorough knowledge of the consequences of those decisions. Therefore, a desire for further research is almost universal in any complex management arena. The value of further study is determined, in part, by the cost in time and resources to obtain new information and the cost of making incorrect decisions without the desired knowledge. In the case of managing forest lands and conserving boreal owls, our knowledge is so limited that well directed research on distribution, habitat use at many scales linked with studies of local demography,...

The breeding range of great gray owls (Strix nebulosa) in the United States includes portions of Alaska, mountains in the western United States including portions of the Cascades and Sierra Nevada ranges and the northern Rockies, and portions of Minnesota, Michigan, Wisconsin, and New York (see Chapter 14 and Map 3). The species is sometimes observed in more southerly states during severe winters. Based on the species' documented distribution (see National Geographic Society 1987, Johnsgard 1988, and others), the owl may occur on National Forests across seven Regions. To document the...

The great gray owl (Strix nebulosa) is the longest, but not heaviest, of the northern forest owls. Distributed holarctically across the boreal forests of North America and Eurasia, the great gray owl extends its range southward into the contiguous states by inhabiting forests other than the boreal type. The subalpine and montane forests of the Cascade Range, Sierra Nevada Range, and the Rocky Mountains support great gray owl populations in central Washington; central and northwestern Oregon; north-central and eastern California; northern, central, and southeastern Idaho; western Montana;...

Many kinds of basic information are required to devise a comprehensive and well-informed conservation strategy for this species. It is imperative that a unified, centrally directed approach be taken to obtain this information. Central oversight will make the effort more efficient and cost effective.

The boreal owl's fairly specific habitat requirements restrict its range in the conterminous U.S. to subalpine forests (see Chapter 9). These forests provide tree cavities, uncrusted snow that facilitates preying on small mammals, and cool microclimates essential for summer roosting. Such forests also provide habitat for the owl's prey which consists primarily of red-backed voles, mice, and other small mammals. Significantly these prey animals often eat lichens and the sporocarps of fungi. Both are common at high elevations or along drainages in the middle and northern Rocky Mountains, the...

The flammulated owl (Otus flammeolus) is a western mountain species associated mainly with ponderosa (Pinus ponderosa) and Jeffrey pine (Pinus jefferyi) forests in the United States and Canada (see Chapter 4). As a neotropical migrant, this small forest owl occurs on national forests in the United States during the breeding season and winters mainly south of the border but also in southern Texas, Arizona, and California. Based on the owl's documented distribution (see National Geographic Society 1987, Johnsgard 1988), it may occur on 89 National Forests across 6 Regions. To establish the...

Ponderosa (Pinus ponderosa) and Jeffrey pine (Pinus jefferyi) forests are ecologically diverse ecosystems. The communities and landscapes in which these trees dominate are variable and often complex. Because of the economic value of resources, people have used these forests extensively.

This forest owl conservation assessment focuses on three species of forest owls that occur on national forest lands in the United States. Sixteen other species of owls also regularly breed in the United States, but these three species were designated "sensitive" on forests in more than one region of the Forest Service in 1992. Within the National Forest System, "sensitive species" are plants and animals whose population viability is identified as a concern by a regional forester. Sensitive species require special management, so knowledge of their biology and ecology is critical. The...

Flammulated (Otus flammeolus), boreal (Aegolius funereus), and great gray (Strix nebulosa) owls occur over a broad portion of North America and each is designated as a "sensitive species" in four or more USDA Forest Service regions. The insectivorous flammulated owl is a neotropical migrant requiring suitable wintering habitat in the extreme southwestern United States, Mexico, and Central America as well as breeding habitat in the mountains of the western United States. Flammulated owls breed predominantly in yellow-pine (Pinus ponderosa and Pinus jeffreyi) forests and are cavity nesters....