Monitoring Bird Populations on National Forest Lands: Chippewa National Forest, 1991

Abstract

Much concern has recently been expressed over possible declines in many birds that breed in eastern North America. Probable causes of such declines are varied, but generally can be attributed to events occurring on both the breeding and/or wintering grounds. Possible influences affecting birds in both regions are changes in habitat structure, including loss of forest habitat, conversion from natural to managed stands, and changes in climate. Changes in bird populations reflect local, regional, and larger scale phenomena; thus, birds may serve as indicators of environmental change that influence the structure and composition of entire ecosystems. In general, the consequences of changes in habitat structure on birds and other wildlife probably have been large but are poorly understood. The composition of bird communities in forests of Minnesota is determined by the dynamic interaction of many factors, including disturbance (e.g., logging, fire, wind), weather (e.g., drought), and habitat (e.g., successional change). Minnesota once was covered by a diverse mix of forested and non-forested habitats. Over the past century, this naturally diverse State has been greatly altered; no longer do extensive stands of undisturbed (by humans) forest remain. Increasing demands on forest resources have the potential to further transform forest cover in Minnesota. Many bird species that breed in the State depend on forest habitats (see Green 1991) during all or part of their life cycle; loss or alteration of forests can have profound consequences on the populations of many species. To understand the effects of different environmental influences (habitat alteration, climate change) on birds, it will be necessary to develop a comprehensive monitoring program that will allow us to detect changes in bird populations. Our objectives for this study in the past year (1991) were to: (1) establish bird monitoring programs in the Chippewa and Superior National Forests; (2) monitor abundance of selected indicator bird species that have been specified by each Forest; (3) monitor abundance of common bird species in each respective Forest; (4) compare point count data gathered in interior forests to data collected along roadsides in the Chippewa, Superior and Chequamegon National Forests; (5) work with NCFES and other Forest Service personnel to coordinate data gathering, data entry, and analyses; and (6) begin refining avian/habitat relationships used to assess forest management activities on breeding bird abundance and distribution.