Birds & Insects

Emphasis will be on determining the influence of land management treatments on nesting and foraging habitat of passerine birds (particularly sagebrush-obligate species). We will measure passerines directly in the woodland experiment, and focus on foraging (arthropod prey) and nesting habitat variables in both woodland and cheatgrass networks.

Three aspects of faunal biodiversity will be evaluated:

(1) Demography and habitats of passerine birds. Passerine birds are of keen interest because sage-obligate passerines are considered to be especially at risk to habitat loss and subsequent population declines given the rapid habitat changes now occurring in sagebrush steppe ecosystems. Species richness and diversity, survival, and productivity of passerine birds will be evaluated. Primary questions to be addressed are:

• What are the dominant habitat characteristics that determine response in the bird community? What spatial and temporal scales are the primary drivers of change in bird populations?

• What are the primary mechanisms by which the bird community responds to changes in quantity, composition, and configuration of their habitat? Does individual or area-specific productivity of birds change relative to habitat treatments?

(2) Food sources of Greater sage-grouse. Currently, all populations of Greater sage-grouse are being considered for federal designation as threatened or endangered. Ground-living arthropods, especially ants, beetles, and spiders, will be studied to better understand how treatments may influence potential foraging habitat for passerine birds and other vertebrates.

(3) Species richness and abundance of butterflies. Butterflies have been considered as indicators of conditions for many other invertebrates, as have passerine birds, thus allowing us to provide further insights about the likely responses of other wildlife species of conservation concern.