Breeding bird monitoring in Great Lakes National Forests: 1991-2000

Abstract

• A total of 135, 168, and 133 stands (1,268 survey points) were surveyed for breeding birds in the Chippewa, Superior, and Chequamegon National Forests, respectively. Surveys have been completed for ten years in the Chippewa and Superior, and for nine years in the Chequamegon NF.• Breeding bird surveys in the St. Croix region of Minnesota have been conducted over the last nine years at 171 points. Surveys in southeast Minnesota have been conducted over the last six years at 211 points.• We were able to examine trends in abundance for 72 bird species in at least one of the five study areas. Fifty species in the Chequamegon NF, 40 species in the Superior NF, 47 species in the Chippewa NF, 36 species in the St. Croix region, and 36 species in Southeast Minnesota were tested.• Twenty-nine species showed a significant increase (P < 0.05) in at least one of the five study areas, and 23 species showed a significant decrease. The Least Flycatcher showed significant increases (P < 0.01) in two study areas and the American Robin increased in three study areas. The Eastern Wood-Pewee, Black-and-white Warbler, and Brown-headed Cowbird showed significant declines (P < 0.01) n two study areas and the Common Yellowthroat and White-throated Sparrow declined in three study areas.• Nine (18%) of the species tested in the Chequamegon NF had increasing trends and nine (18%) had decreasing trends. In the Chippewa NF, 12 (26%) of the species tested increased significantly and 10 (21%) decreased. Seven (18%) of the species tested in the Superior NF had significant increasing trends, and seven (18%) had decreasing trends. In the St. Croix study area, six (17%) of the species tested increased significantly, and seven (19%) decreased. In the Southeast, ten (28%) species increased significantly and three (8%) decreased.• The regional analysis of the three National Forests combined revealed five species (14%) with significant increases; Yellow-bellied Flycatcher, Least Flycatcher, Redbreasted Nuthatch, American Robin, and American Redstart. Six species (17%) had significant decreases: Eastern Wood-Pewee, Ovenbird, Canada Warbler, Scarlet Tanager，Song Sparrow, White-throated Sparrow.• Over 70% of the decreasing species nest on the ground, which is significantly more than would be expected. Ground-nesting species that declined in multiple study areas, such as the White-throated Sparrow, Common Yellowthroat, Black-and-white Warbler, and Ovenbird, warrant closer attention in the future.• Neither increasing nor decreasing species showed a relationship with any particular migration strategy, although no permanent residents declined significantly.• The abundance of many species varied over the survey period but did not show significant increases or decreases. A common thread among many species was a decline in abundance between 1994 and 1996, with an increase from 1996 to 1998. The reason for this pattern is unclear, but it may be related to winter and spring weather.