Bird Populations Associated with an Electric Transmission Right-of-Way

A 2-year study of bird populations was conducted along a 230-kV transmission line right-of-way (ROW) in spring (June) and summer (August) 2000 and 2001. Forty-four species were observed on the ROW during 2000 and 2001. In 1987 and 1988 combined, 39 species were noted on the ROW; thus, bird populations have changed relatively little over the past 13 to 14 years. In both 2000 and 2001, slightly more species occurred on the ROW in summer (n = 26-32) than in spring (n = 25-26), and considerably fewer species were noted in the adjacent forest in both spring (n = 8-13) and summer (n = 7). Common bird species (50 individuals/100 ha/day) on the ROW were those adapted to brushy or early successional habitat. Most species were found in the low-volume basal spray and foliage spray units (n = 29 and 28 species, respectively), and fewest species were noted in the handcutting unit (n = 19 species). Considerably more bird species were observed in border zones than in wire zones of the ROW in 2000 and 2001 combined (n = 39 versus 17 species, respectively). Moreover, abundance of all bird species combined was nearly fourfold higher in border zones (1,530 individual birds/100 ha/day) than in wire zones (393 birds/100 ha/day). Thus, the border zone is a very important habitat for birds along a ROW, with its combination of shrub-forb-grass cover type.