Effects of logging on bird populations in British Columbia as determined by a modified point-count method.

Abstract

Breeding bird populations in mature mountain hemlock Tsuga mertensiana and in Engelmann spruce Picea engelmannii-subalpine fir Abies lasiocarpa forests and clearcuts were surveyed. In steep, valley-oriented mountain hemlock forests the uncut strip of timber up-slope of the clearcuts supported the same bird communities as did continuous forest extending from below alpine to the valley bottom. In Engelmann spruce-subalpine fir forests, bird communities in unlogged stands between clearcuts were similar to those in large uncut areas. In forests where clearcut logging occurs there is a net loss to mature forest bird populations, but in residual stands the bird communities continue to exist at similar densities. Also, logging results in a different bird community which occupies the clearcuts. A single-visit modified point-count method was developed for censusing the rugged, heavily forested terrain. The method combines feature of the Finnish line transect and point-count methods. -from Authors