Abundance of Grassland Sparrows on Reclaimed Surface Mines in Western Pennsylvania

Abstract

Grassland songbird populations have experienced some of the most severe declines of any migratory songbird guild in North America and are continuing to disappear from portions of their historic ranges. Habitat loss and degradation have been implicated as primary causes of these declines. However, intensive surface coal mining and subsequent reclamation in western Pennsylvania have created large tracts of grassland habitat during the past 30 to 40 years. We estimated the area of habitat suitable for breeding grassland songbirds on reclaimed strip mines in nine western counties of Pennsylvania using a stratified random sample design. We used distance sampling methods to estimate abundance of Henslow’s (Ammodramus henslowii), Savannah (Passerculus sandwichensis), and Grasshopper (Ammodramus savannarum) Sparrows. We estimated that 35,373 ha (95 percent CI = 26,758 - 46,870) of reclaimed-mine grassland suitable for breeding grassland songbirds were present in our 1.85 × 106 ha study area in 2001. Henslow’s, Savannah, and Grasshopper Sparrow abundances were 4,884 (95 percent CI = 2,128 – 8,460), 1,921 (95 percent CI = 848 – 2,790), and 9,650 (95 percent CI = 4,390 – 13,614) singing males, respectively. Reclaimed-mine grasslands in western Pennsylvania supported substantial grassland songbird populations during the 2002 breeding season. Therefore, management of reclaimed surface mine areas as grassland reserves may help prevent populations of some species, notably Henslow's Sparrow, from becoming endangered.