Bald eagle (Haliaeetus leucocephalus alaskanus) nesting related to forestry in southeastern Alaska

Abstract

There were 136 nests located by aerial survey along 225 miles of beach in six logged plots and six virgin plots. Nest densities during the three years were 0.20, 0.23, and 0.20 active nests per beach mile. Islets present within 2 miles of a logged main shore provided nesting territories for eagles not able to find suitable nest sites along the logged shore. Spatial distribution of active nests indicated a 1.25 mile territory radius per nesting pair. Statistical comparison (Mann and Whitney U test) of mean territory size found in logged versus virgin plots showed no significant difference in territory size between the two plot types. Nests located in beach fringe timber remaining after harvesting were utilized frequently because of the lack of alternate nest sites in the immediate vicinity; these nest sites were highly susceptible to wind throw. Storm damage resulted in the loss of 20 per cent of the known nests during winter 1968-1969. It is recommended that buffer zones (10 chain radius - 660 feet) around eagle nests be maintained during harvesting, and that logging activity in the vicinity of nesting eagles be curtailed during April and May. Also, smaller, scattered timber sales should be promoted to ensure that extensive beach strip logging does not remove potential nest sites along miles of shoreline.