Are There Snags in the System? Comparing Cavity Use among Nesting Birds in “Snagrich”and “Snag-poor” Eastside PineForests1

We compared the density of snags, snags with cavities, and cavity-nesting bird use at two sites in northern California: Blacks Mountain Experimental Forest, a site with large trees and large snags because of protection from logging, contrasted with the Goosenest Adaptive Management Area, where a century of logging left this forest with few large trees and snags. Indeed, there was a threefold difference between sites in total snags, and a fifteenfold difference in cavity-nesting bird use. However, we feel finding a “snags per acre” prescription is inadequate, as tree size, rate of snag generation, and mode of tree death have been disrupted this past century. We argue that understanding the interactions between fire, bark beetles, woodpecker foraging and excavating, sapwood decay organisms, snag “demography,” and cavity-nesting species ecological requirements apart from simply cavities are required in place of simply counting snags in landscapes.