Avian habitat relationships in pinyon-juniper woodland

Publication Type:

Journal Article

Authors:

Sedgwick, James A.

Source:

Wilson Bulletin, Wilson Ornithological Society, Volume 99, Issue 3, p.413-431 (1987)

Call Number:

A87SED02IDUS

URL:

https://sora.unm.edu/node/130531

Keywords:

Black-throated Gray Warbler, Blue-gray Gnatcatcher, Brewer's Sparrow, Catharus guttatus, Chipping Sparrow, Dendroica nigrescens, dusky flycatcher, Empidonax oberholserii, Green-tailed Towhee, Hermit Thrush, Juniperus osteosperma, Mourning Dove, Pinus edulis, pinyon pine, Pipilo chlorurus, Pipilo erythrophthalmus, Polioptila caerulea, Pooecetes gramineus, Rock Wren, Rufous-sided Towhee, Salpinctes obsoletus, Solitary Vireo, Spizella brewerii, Spizella passerine, Utah juniper, Vermivora virginiae, Vesper Sparrow, Vireo solitarius, Virginia's Warbler, Zenaida macroura

Abstract:

Habitat relationships of breeding birds were examined in northwestern Colorado in pinyon-juniper (Pinus edulis-Juniperus osteosperma) woodland and in openings where most overstory trees had been knocked down by anchor chaining. Vegetation characteristics and physical habitat features were measured in 233 0.04-ha circular plots around singing males of 13 species of birds from 15 May to 15 July 1980. Thirteen-group discriminant function analysis ordinated bird species along three habitat dimensions described by (1) canopy height; (2) slope, shrub size, and shrub species diversity; and (3) percentage canopy cover, large tree density, distance from a habitat edge, litter cover, and green cover. Woodland, open-area, and intermediate edge species were clearly segregated along the first discriminant axis, and species' associations with shrubs, inclination, ground cover, and edges were revealed by the ordinations along the second and third discriminant axes. Two-group discriminant analyses comparing occupied and available plots identified additional and more specific habitat associations. For example, Hermit Thrushes (Catharus guttatus) were associated with mature forested habitats and forest interiors, Virginia's Warblers (Vermivora virginiae) favored steep, oak-covered draws, Rock Wrens (Salpinctes obsoletus) selected areas where percentage log cover and small tree density were high, and Dusky Flycatchers (Empidonax oberholseriy preferred shrubby slopes with scattered large trees near woodland edges.