We conducted a 2-year study of bird populations on the Green Lane Research and Demonstration Project, which is located along a 500-kV transmission line right-of-way (ROW) of the Philadelphia Electric Company, in the Piedmont Province, Montgomery County, Pennsylvania, U.S., in spring and summer 2001 and 2002.
The objectives of our study were to (1) determine the diversity and relative abundance of bird populations in spring versus summer on the ROW, (2) compare bird use among five representative treatment units of the ROW, and (3) compare use of wire zones versus border zones on the ROW. In addition, bird populations in this study were compared to those observed on the ROW in 1987 and 1988. Forty-four species (including one hybrid) were observed on the ROW during 2001 and 2002. In 1987 and 1988 combined, 42 species were noted on the ROW; thus, despite continued mechanical and herbicidal maintenance of the right-of-way, the bird community has changed very little over the past 15 years.
More species were observed on the ROW in spring than in summer. Common bird species on the ROW in one or both seasons were those adapted to early successional or edge habitats. Total abundance of all species combined, however, was higher in summer than in spring, in part because of the presence of many family groups (parents and fledgling young).
Most species were found in the mowing plus herbicide unit and the fewest were noted in the foliage-spray unit. Considerably more birds were observed in border zones than in wire zones of the ROW. Thus, border zones are very important habitat for birds along a ROW, with its combination of shrub–forb– grass cover type.