Responses of cavity-nesting birds to stand-replacement fire and salvage logging in ponderosa pine/Douglas-fir forests of southwestern Idaho

In spring 1994, the Intermountain Research Station (now Rocky Mountain Rese arch Station), Boise National Forest, and Region 4 of the Forest Service in itiated long-term studies on bird responses to different fire conditions in ponderosa pine/Douglas-fir forests of southwestern Idaho. The first phase of the project is to evaluate effects of high-intensity wildfire on cavity- nesting bi rds and their associated habitats. During spring/summer 1994-199 6 we monitored 695 nests of nine cavity-nesting bird species (including thr ee Forest Service Sensitive Species: Black-backed, White-headed, and Lewis' woodpeckers) and measured vegetation at nest sites and at 90 randomly loca ted sites. The burned forests used for study areas were created in 1992 and 1994 by primarily high-intensity wildfire, thus most standing trees were s nags. Nests and vegetation were monitored in three treatments: standard-cut salvage logged, wildlife-prescription salvage logged, and unlogged control s. Tree densities for small diameter trees (>23 cm to less than or equal to 53 cm [>9" to less than or equal to 20"] diameter breast height [dbh]) in the unlogged units averaged 81 snags per ha (33 per acre) and for larger tr ees (>53 cm dbh [>20"]) averaged 17 snags per ha (7 per acre). In salvage-l ogged units about 50% of the trees were harvested, tree densities for small trees averaged 43 snags per ha (17 per acre) and for large trees ave raged 5 snags per ha (2 per acre). Lewis' Woodpecker was the most abundant (208 nests) and successful cavity nester on the 2-4 year-old burns, while Black- backed and White-headed woodpeckers were rare (23 nests). Lewis' Woodpecker and American Kestrel experienced the highest nesting success in the salvag e-logged units, whereas Northern Flicker and Hairy Woodpecker were most suc cessful in the unlogged units. All bird species selected nest sites with hi gher tree densities than that measured at random sites, and cavity nesters as a group selected clumps of snags rather than snags that were retained in uniform, evenly-spaced distributions. Among bird species, Black-backed Woo dpeckers used nest sites with the highest tree densities, while Lewis' Wood peckers selected relatively open nest sites. Cavity-nesters as a group sele cted larger diameter and more heavily decayed snags than that expected base d on availability of such snags. Snags with the highest probability (>85%) of being classified as nest trees were characterized by heavy decay and bro ken tops that pre-dated the wildfire. We discuss management implications of stand-replacement fire and post-fire salvage logging for cavity-nesting bi rds. Future plans are outlined, including bird and plant responses to diffe rent fire conditions (stand-replacement fire, fire suppression, and prescri bed fire). The intent of this work is to provide information on the action and no action alternatives to the Forest Health Initiative.