Treesearch

The Wilderness Act of 1964 established a National Wilderness Preservation System, and this publication is a compilation of selected information about every wilderness within this System. For each wilderness, the following information is given: legally correct wilderness name; public law that established the wilderness; date the enabling law was signed by the President; acreage designated in the enabling public law; modifying public law or laws that affected the name, boundary, or administration; current total acreage reported by the administering agency, the agency or agencies with current...

In this chapter, we describe research needs for the conservation of the cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) in Arizona. Estimates of population size, structure, and dynamics, as well as demographic data, are needed for the recovery team to formulate sound population objectives. Habitat loss due to residential development may represent the primary threat to the pygmy-owl, yet the impacts of other human activities and of disease or predation have not been evaluated. Studies of the cactus ferruginous pygmy-owl’s habitat requirements are essential to determine the...

Using broadcasted conspecific calls, nest boxes, miniature-video cameras, a fiberoptic stratascope, and radio-telemetry, researchers from Caesar Kleberg Wildlife Research Institute conducted studies to assess the viability and profile the natural history of ferruginous pygmy-owls in Texas (Mays 1996, Proudfoot 1996a, Proudfoot and Beasom 1996, Proudfoot and Beasom 1997, Proudfoot and Radomski 1997). Techniques used were specifically designed or adapted to address the concerns of this species (e.g., minimizing risks of nest abandonment resulting from nest inspection). In this chapter, we...

The habitat needs of the ferruginous pygmy-owl (Glaucidium brasilianum) are poorly understood. In the tropics, this common bird of prey inhabits many distinct vegetation communities or environments (e.g., Monroe 1968, Meyer de Schauensee 1970, Stiles and Skutch 1989, Sick 1993). A resident of woodlands and open forests, it is also found in the open, perched on telephone lines or fence posts (Ridgely 1976). At the northern edge of its range, the ferruginous pygmy-owl has been recorded in riparian woodlands and thickets (Bendire 1888, Breninger 1898, Oberholser 1974), live oak (Quercus...

In 1993, the Arizona Game and Fish Department (AGFD) began formal population surveys in an attempt to document the numbers and distribution of cactus ferruginous pygmy-owls (Glaucidium brasilianum cactorum) in Arizona. Surveys were initiated to gather information on this little-known subspecies which was considered for listing at the time. Prior to 1993, birders and avian biologists had conducted many informal surveys in a sporadic and opportunistic fashion. However, the information derived from those surveys was limited and often inaccessible, and contributed little to the overall...

The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) was discovered in the U.S. by Bendire in 1872 in the Tucson area (Coues 1872). During the next five decades, naturalists collected many specimens of this owl and typically described the subspecies as common or fairly common along some streams and rivers of central and southern Arizona. A common view among regional ornithologists is that the cactus ferruginous pygmy-owl’s Arizona population sharply declined around 1950 (see Monson and Phillips 1981). As a result of a petition (Galvin et al. 1992), the cactus ferruginous...

The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) is a small, cryptic owl that is often difficult to observe. Its natural history and conservation needs are poorly understood. Despite ongoing research in Texas and Arizona, the available information remains limited. In addition, factors influencing demographics (e.g., habitat configuration, causes of mortality and reproductive failure, and prey availability) may vary geographically, increasing the need for information from all parts of the range. Without a significant commitment to additional research, management and...

In March 1997, the U.S. Fish and Wildlife Service listed the Arizona population of the cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) as endangered under the Endangered Species Act (U.S. Fish and Wildlife 1997). Federal listing for the owl in Arizona resulted from a petition submitted in 1992 to the U.S. Fish and Wildlife Service (Galvin et al. 1992, U.S. Fish and Wildlife 1994). It was finalized based on historical and current evidence suggesting a significant population decline of this subspecies had occurred in Arizona and the owl population in this state was now nearly...

This report is the result of a cooperative effort by the Rocky Mountain Research Station and the USDA Forest Service Region 3, with participation by the Arizona Game and Fish Department and the Bureau of Land Management. It assesses the state of knowledge related to the conservation status of the cactus ferruginous pygmy-owl in Arizona. The population decline of this owl has been attributed to the loss of riparian areas before and after the turn of the 20th century. Currently, the cactus ferruginous pygmy-owl is chiefly found in southern Arizona in xeroriparian vegetation and well-structure...

Gambel oak (Quercus gambelii Nutt.) covers 3.75 million hectares (9.3 million acres) of the western United States. This report synthesizes current knowledge on the composition, structure, and habitat relationships of gambel oak avian communities. It lists life history attributes of 183 bird species documented from gambel oak habitats of the western United States. Structural habitat attributes important to bird-habitat relationships are identified, based on 12 independent studies. This report also highlights species of special concern, provides recommendations for monitoring, and gives...