Spatial variation in songbird demographic trends from a regional network of banding stations in the Pacific Northwest

Abstract

ABSTRACT Many North American landbird populations have declined in recent decades, including those that occupy Western forest habitats. Long-term monitoring of abundance and vital rates allows us to detect species and habitats of concern, and to identify potential management actions. Here, we analyze capture data from a regional network of 10 banding sites in the Klamath-Siskiyou Bioregion, USA, to examine demographic trends for 12 Western forest bird species from 2002 to 2013. Adult abundance declined significantly in some breeding populations of Audubon's Yellow-rumped Warbler (Setophaga coronata auduboni) and Purple Finch (Haemorhous purpureus), and near-significantly in Oregon Dark-eyed Junco (Junco hyemalis oreganus). We observed significant declines in productivity of the Purple Finch and Spotted Towhee (Pipilo maculatus). Black-headed Grosbeaks (Pheucticus melanocephalus) and Yellow-breasted Chats (Icteria virens) increased significantly in adult abundance, but with variation among sites. Productiv...