Accipiter Use of Pinyon-Juniper Habitats for Nesting in Northwestern Colorado. BLM Technical Note 435

摘要

Three accipiter species breed in North America, the Sharp-shinned Hawk (Accipiter striatus), Coopers Hawk (A. cooperii), and Northern Goshawk (A. gentilis). Accipiters are known to use a variety of habitats for nesting throughout the United States, but in the West, attention has focused primarily on conifer-dominated habitats. Very little published information is available on accipiter nesting use of pinyon-juniper habitats (in most of western U.S., typically Pinus edulis or monophylla Juniperus spp.), although use is known outside the nesting season (e.g., Northern Goshawk use of pinyon-juniper habitats during post-fledgling dispersal and winter periods; Drennan and Beier 2003, Kennedy and Ward 2003, Wiens et al. 2006). The scarcity of information on nesting use of pinyon-juniper habitats in part may be due to a bias toward searching for nests in habitats assumed a priori to be suitable. It is also possible, however, that pinyon-juniper habitats do not regularly provide the individual tree, habitat, or landscape-structure characteristics sought by nesting accipiters, as pinyon-juniper woodlands are often more shrub-like and open relative to other conifer woodlands.