Do mature forest birds prefer early-successional habitat during the post-fledging period?

Abstract

Recent studies have highlighted the importance of the post-fledging period to bird populations, suggesting that the importance of this portion of the life cycle is equal to or greater than the nesting period. Nevertheless, few studies have compared abundance of forest nesting species between mature forest and early-successional habitats while controlling for differences in detectibility and for biases associated with comparing low stature shrubby vegetation and tall stature forests. We investigated habitat use by forest-nesting birds during the post-fledging period in 2004 using both point counts and mist-netting in regenerating clearcuts, maintained wildlife openings, and mature forest in the White Mountain National Forest of New Hampshire, USA. We captured 1151 individuals of 50 species with mist-nets and detected 1267 individuals of 50 species with point counts during the course of the study. Of the nine mature forest-nesting species for which we had sufficient samples, seven were more abundant in early-successional habitats than mature forest. Additionally, these species highest densities were in large clearcuts with tall, complex vegetation structure and large wildlife openings with tall vegetation and standing dead vegetation. Our findings provide the first comparison of mature forest bird abundance between mature forest and early-successional habitat during the post-fledging period using estimates corrected for detectibility and for habitat stature. These results suggest that mature forest birds might actually prefer early-successional habitat to mature forest during the post-fledging period, which has important implications for managers and conservationists weighing the effects of management on early-successional versus mature forest birds.