Songbird response to partial-cut logging in the boreal mixedwood forest of Alberta

We documented the responses of songbird communities to two levels of partial-cut logging (30.1% and 40.3% canopy cover retention) relative to structured clearcuts (8.5% cover retention) and unharvested controls in old aspen (Populus tremuloides Michx.) stands in the boreal mixedwood forest of northern Alberta. Bird communities were censused using a 100-m fixed-radius point-count technique before and after logging on the same cut blocks to obtain estimates of species richness and bird abundances. Harvesting reduced both species richness and bird abundance, but both parameters declined less in partial cuts than in clearcuts. Ground-dwelling birds had similar abundance before and after harvesting, but the abundance of individuals of tree- and shrub-inhabiting birds decreased with the amount of remaining vegetation cover. Fourteen of 36 species declined significantly in abundance following logging. Seven of eight species that were absent from clearcuts were retained at very low abundances in partial cuts. Pending the collection of longer term data on reproductive success, we suggest that retention levels of residual vegetation up to 40% on cutover areas can benefit bird communities when used as one technique in a large-scale forest management strategy.