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Avian Nesting Success in a Selectively Harvested North Temperate Deciduous Forest

2001; Wiley; Volume: 15; Issue: 6 Linguagem: Inglês

10.1046/j.1523-1739.2001.00226.x

1523-1739

Scott K. Robinson, W. Douglas Robinson,

Ecology and Vegetation Dynamics Studies

Abstract: Predators and parasites of bird nests often reach maximum abundance near ecotonal edges, potentially causing reproductive failure for birds breeding near edges. Timber‐harvesting methods in which single or small groups of trees are removed from forested lands may maximize amounts of edge created within forest tracts. We evaluated the effect of internal edges created by timber harvest in Trail of Tears, a deciduous forest in southern Illinois ( U.S.A.). We measured the nesting‐success and brood‐parasitism rates of four songbird species, the Acadian Flycatcher ( Empidonax virescens ), Kentucky Warbler ( Oporornis formosus ), Wood Thrush ( Hylocichla mustelina ), and Northern Cardinal ( Cardinalis cardinalis ). Each species bred in each of three forest management units: compartments selectively harvested within the previous 6 years (recent cuts); compartments 10 to 15 years post‐harvest (older cuts); and compartments remaining uncut for at least the last 40 years. Levels of brood parasitism by Brown‐headed Cowbirds ( Molothrus ater ) were high throughout the forest but were significantly higher in the selectively harvested compartments for Acadian Flycatchers and Kentucky Warblers. Nest predation differed among compartments in species‐specific patterns. None of the four species suffered consistently greater losses of nests in cut than uncut forest in Trail of Tears. For three of the four species, however, rates of nest failure were consistently higher in Trail of Tears than in two other large tracts of uncut forest in the southern Illinois region, suggesting that predator populations may be greater in Trail of Tears than in other large forest tracts. Overall, the results suggest that selective logging added little to existing fragmentation effects in this landscape in which levels of nest predation and brood parasitism are chronically high. Although the creation of internal edges appeared to have few detrimental effects on these two measures of songbird productivity, effects may differ in landscapes with greater forest cover or different predator and brood‐parasite assemblages.