Avian communities on utility rights-of-ways and other managed shrublands in the northeastern United States

Abstract

We studied bird density and nesting success on utility rights-of-way (ROW) managed primarily by selective herbicide application in New York, Massachusetts and Maine. For comparison, we also estimated bird density in ROW managed by cutting in New Hampshire and New York and in shrublands managed by fire in the Finger Lakes National Forest (FLNF), New York. On herbicide-managed ROW, we detected a mean of 14.3 individuals and 12.2 species per point count, including many species of early-succession habitat that are declining throughout northeastern United States. Nesting success in forested landscapes of New York, Maine, and Massachusetts was 55% on the ROW, 69% in forests within 20 m of the ROW, and 63% in forests more than 20 m from the ROW. Brown-headed cowbirds ( Molothrus ater) parasitized 5.3% of the nests and reduced host recruitment by even less. This suggests that ROW in forested areas support high production of shrubland birds and do not exert a measurably harmful effect on forest-nesting birds. Selective herbicide application on ROW sustained shrubland vegetation and supported high densities and high nesting success. Mechanical cutting lowered the structural diversity of vegetation the following spring and was associated with fewer individual birds and species. Cool burns in early spring produced a high structural diversity of herbs, shrubs and trees and supported a high density of birds and bird species. Long-term maintenance of shrublands by burning will require supplemental cutting to remove saplings. As reforestation continues to reduce shrubland habitat, probably below pre-colonial levels, active management for early-succession habitat will be necessary to sustain current population levels of numerous species.