Looking Out for the Pileated Woodpecker. Science Findings, Issue One Hundred Nine, January 2009

摘要

The pileated woodpecker is a species of conservation concern and a keystone species in mature and old forests of the Pacific Northwest. In the Blue Mountains of northeast Oregon, researchers from the PNW Research Station in La Grande, Oregon, studied the effects of natural and human-caused disturbance on pileated populations and their habitat over a period spanning from 1973 to 2005. During this time, several pervasive insect outbreaks transformed the forest characterized by predominantly live conifers with dense canopy cover (prime pileated habitat) to one with increasing numbers of snags and downed wood. Logging for forest restoration and fuel reduction treatments also took place, further impacting habitat for the birds. The researchers were able to compare the effects on pileated populations at various stages as their environment changed. They found, surprisingly, that despite heavy tree mortality, the number of nesting pairs, their reproductive success, and home range locations remained fairly consistent--provided that dead trees and logs remained abundant and extensive logging had not occurred. Conversely, nesting pair numbers and reproductive success decreased significantly where extensive regeneration cuts eliminated many nest and roost trees, as well as snags and downed wood where the birds forage for insects.