GRASSLAND SONGBIRD NEST SITE SELECTION PATTERNS IN NORTHCENTRAL MONTANA

Abstract

Abstract We explored nest site habitat selection patterns for six grassland passerine species in northcentral Montana: Sprague's Pipit (Anthus spragueii), Savannah Sparrow (Passerculus sandwichensis), Grasshopper Sparrow (Ammodramus savannarum), Baird's Sparrow (A. bairdii), Chestnut-collared Longspur (Calcarius ornatus), and Western Meadowlark (Sturnella neglecta). We quantified habitat characteristics at sites chosen for nesting and compared them to randomly selected sites, both spatially and temporally. Using discriminant analysis, two species groups were discernable based on a combination of habitat characteristics, which were distinct from random sites. Nest sites had greater foliage height and density than random sites. This pattern generally was shown most strongly by Western Meadowlarks, Baird's, and Savannah sparrows. Three bird species selected nest patches (5-m radius plots centered on nests) having little or no clubmoss (Selaginella densa) cover, which was one of the most powerful discriminati...