Snag Retention Increases Bird Use of a Clear-Cut

Abstract

Birds were counted during the breeding season from 1977 to 1981 in 4 snag and 4 snagless plots (80 X 250 m) in an east Texas clear-cut to assess effects of snag retention on the bird community. After 4 years, 44 of the original 75 snags remained. Species richness, bird abundance, bird species diversity, and equitability were all higher (P < 0.05) in plots with snags than in snagless plots. Cavity-nesting birds occurred on plots with snags but were virtually absent from snagless plots. Other species used snags for foraging and perching and were more abundant on plots with snags. Retention or creation of snags is recommended for bird management in clear-cuts. J. WILDL. MANAGE. 47(3):799-804 Increased demand for wood products (U.S. Dep. Agric. 1973) has brought more intensive management of forests. Lands are being fully stocked with fast-growing trees and harvest rotations are being shortened. Present management trends increase homogeneity of commercial forests. Decaying wood in forest stands has no commercial value and is being eliminated. High-yield timber management replaces stands of snags (dead or dying trees) and old growth with young vigorous stands. Forest birds evolved in association with natural forest stands that usually contained substantial decayed wood. Birds use decaying wood for cavity nests, winter roost sites, and as a foraging substrate. Approximately 85 species of North American birds use cavities in dead or deteriorating trees (Scott et al. 1977); many of these birds occur in southern pine forests (LeGrand and Hamel 1980). Primary cavity nesters, e.g., woodpeckers, excavate their own nest cavity, mostly in decaying wood (Conner et al. 1975). Many of these cavities are later used as nest and roost sites by secondary cavity nesters. Balda (1975) found secondary cavity nesters composed approximately 50% of the breeding bird population in natural ponderosa pine (Pinus ponderosa) stands that contained substantial decayed wood. In southern forest ecosystems the role of snags and their relationships to birds have not been fully established. This study was designed to investigate the following questions: (1) what birds use snags and in what ways?, (2) can bird density and diversity in early-succession pine stands be i creased by maintaining snags?, and (3) how long do snags stand and how long do birds use them? We thank J. A. Jackson, B. R. McClelland, and V. E. Scott for reviewing a draft of this manuscript and the Southern Timberlands Division of St. Regis Paper Co. for use of their land for this study.