Effects of selective logging on forest bird populations in a fragmented landscape

We evaluated the effects of perforation, or the creation of small gaps, wit hin a mature, deciduous forest in southern Illinois (U.S.A.) opt abundances of breeding birds. Openings of 0.02-0.4 ha were created by group and singl e-tree selection logging within a 2000-ha tract of forest. We used point co unts to compare abundances of birds in uncut forest with those in similar a djacent forest compartments that were recently cat (1-5 years previously) a nd less recently cut (10-15 years earlier). Most species of forest birds we re not significantly less common in logged tracts. Only Red-eyed Vireos (Vi reo olivaceus) and Ovenbirds (Seiurus aurocapillus) were significantly more numerous in uncut forest, but the vireo responded negatively to cuts at si tes on ridges only, not in ravines, whereas Ovenbird populations differed s ubstantially among years. Blue Jays (Cyanocitta cristata), important nest p redators, were significantly more abundant in cut than uncut forest, but br ood parasitic Brown-headed Cowbirds (Molothrus ater) showed no consistent d ifferences. Populations of gap-dependent species such as Hooded Warbler (Wi lsonia citrina),, Indigo Bunting (Passerina cyanea), White-eyed Vireo (Vire o griseus), and Carolina Wren (Thryothorus ludovicianus) were dramatically larger in recently cut forest, with populations of most species reaching a peak 2-3 years after cutting Between 5 and 10 years after cutting nearly al l gap-dependent species had returned to population levels comparable to tho se in uncut forest. Species dependent upon larger gaps, such as Yellow-brea sted Chat (Icteria virens), Blue-winged Warbler (Vermivora pinus), and Prai rie Warbler (Dendroica discolor), were absent. We conclude that the first c utting cycle in selective logging had only a miller effect on the forest bi rd community composition and created a short-lived availability of habitat for gap species. In the southern Illinois landscape selective logging appea red to add little to the existing effects of forest fragmentation. Effects of perforation may differ in more continuous forested landscapes however, a nd may be influenced by total basal area of timber removed and by the lengt h of the inter-cut interval.