Monitoring Bird Populations on Rice Lake National Wildlife Refuge

Abstract

Rice Lake National Wildlife Refuge (NWR) in north central Minnesota (Aitkin County) is located at the southern border of the major contiguous forested area of northern Minnesota. The refuge is approximately 18,000 acres in size of which over 5,300 acres is forested (Figure 1). The forested area can be generally divided into three types: (1) a large block of forest in the southeast corner of the refuge that can be regarded as forest interior habitat; (2) smaller stands of forest (fragmented timber stands) in the west and southwest area of the refuge; and (3) bog islands located in the northern portion of the refuge. A timber management plan has been completed for the refuge. The plan divides the refuge into 10 areas and each year an area is reviewed and given a treatment. Treatments are generally either to harvest or for no action. Future management decisions would be aided by a more thorough understanding of effects of management activities on wildlife in the refuge, and in particular effects on forest birds. Special consideration should be given to neotropical migrants (species that breed in North America and winter in Latin America or the Carribean), because several species have been declining on a national level (Robbins et al. 1989). Species that have shown the greatest declines are those dependent on contiguous forests or large tracts of grassland. Although causes of such declines are complex (Blake et al. 1992), forest fragmentation in breeding areas and deforestation in wintering areas are two major contributing factors (Terborgh 1989). Breeding bird population trends in Minnesota over the past 25 years do not reflect national level trends on a species specific basis (based on breeding bird surveys (Janssen 1990)). However, these data are based on limited coverage of roadside counts (53 total) completed in the State. The overall purpose of our research project was to identify bird species and their relative abundance in forested habitats of the refuge. These data will help determine management activities and land use practices on the Rice Lake NWR. Specific objectives for this study were to: (1) determine the distribution, relative abundance, and species composition of birds in forested habitats on the Rice Lake NWR; (2) begin refining avian/habitat relationships so that they can be used to aid forest management activities; (3) determine differences in bird community composition between fragmented and unfragmented forest areas of the refuge; and (4) integrate data gathered in the Rice Lake NWR with a large scale avian monitoring study to determine landscape level affects on bird species abundance and distribution in the State.