managing urban and rural rights-of-way as potential habitats for grassland birds

Urban grassy rights-of-way (ROWs) such as along transmission lines could be managed cumulatively as collections of potential grassland habitats to contribute to the conservation of grassland birds. To optimize conservation opportunities, managing urban ROWs for grassland birds may require reductions in frequent mowing and spraying and may also depend on the suitability of landscape structure within the urban environment. We compared effects of mowing regime relative to effects of the matrix surrounding ROWs on grassland bird abundance and occupancy along 48 ROWs in and surrounding Winnipeg, Manitoba, in 2007-2009. We used both hierarchical distance-sampling and multiseason occupancy modeling methods to account for effects of urbanization (e.g., traffic noise), observer experience, time of season, and survey time in the morning on the probability of detecting birds at study sites. We did not find differences in detection of grassland birds due to urbanization, but we did find effects of time of season, survey time in the morning, and observer experience. After accounting for availability, we found that several species declined along ROWs that were surrounded by more urban or wooded land. Western Meadowlark occupancy increased as the amount of grassland within 100 m of ROWs increased. Savannah Sparrow showed some evidence of increasing with mowing, whereas Clay-colored Sparrow showed some evidence of decreasing with mowing, although these species and Western Meadowlark also increased within hayed ROWs. We conclude that urban ROWs managed as grassland bird habitats will probably attract more individuals and species if there is less nearby urban or wooded land and more grassland, and within which there is a mixture of unmowed and hayed ROW sections.