Forest Bird Population Trends in Minnesota and Northwestern Wisconsin Forests 1991-1997

Abstract

A forest breeding bird monitoring program was established in 1991 to provide data on abundance trends over time for individual species and community parameters in the Chippewa, Superior, and Chequamegon National Forests; Minnesota’s St. Croix River Valley; and southeast Minnesota. Our objective was to identify species that have statistically significant population trends for each study area and all study areas. Our results were compared with Breeding Bird Survey (BBS) statewide trends for Minnesota for 1980-1996. Across all study areas, 57 species had significant linear trends: 31 species (54%) increased, 16 species (28%) decreased, and 10 species (18%) increased in one and decreased in others. Eleven species had increasing trends in two or more study areas including the Yellow-bellied Sapsucker, Red-breasted Nuthatch, Winter Wren, Solitary Vireo, Red-eyed Vireo, Chestnut-sided Warbler, Magnolia Warbler, Yellow-rumped Warbler, Blackburnian Warbler, American Redstart, and Chipping Sparrow. Six species had decreasing trends in two or more study areas including the Downy Woodpecker, Golden-crowned Kinglet, Black-and-white Warbler, Indigo Bunting, Brown-headed Cowbird, and Purple Finch. Many of these species had similar significant regional trends. In comparison, most (82 %) Minnesota BBS trends indicated no change in abundance over 1980 to 1996.