Species Assessment for Sage Thrasher (Oreoscoptes Montanus) in Wyoming
Author(s):Publication Date: 2004-12
Douglas A Keinath
Tags: WLCI, WLCI Agency Report, BLM
The sage thrasher (Oreoscoptes montanus), a sagebrush-steppe obligate that relies on large
expanses of sagebrush-steppe for successful breeding, is recognized by Canada and several U.S.
state agencies as a sensitive species that is apparently at risk based on loss or alteration of breeding
habitat and decreasing population trends. In this context, habitat alteration refers to modification
of any component of the required habitat mosaic, (e.g., presence and quality of tall big sagebrush
(Artemesia spp.), adequate cover, and increased vertical and horizontal heterogeneity) that might
directly decrease suitability for nesting habitat.
Primary threats to O. montanus habitat are agricultural field cultivation, domestic grazing,
invasion of exotic plant species, change in fire frequency, fragmentation from oil and gas
development, and increased recreational use.
To maintain populations of sage thrasher, it is important to protect and maintain extensive,
intact shrubsteppe habitats and rehabilitate sagebrush habitats that have been lost, fragmented, or
degraded. In addition, it is essential to understand the impacts of habitat alteration on local and
range wide O. montanus populations. More specific issues of conservation concern are discussed
later in this assessment. Fulfilling the information needs listed at the end of this document will
clarify population status and contribute to refining these conservation goals.