The potential for adverse effects to grassland birds, one of the most imperiled groups of birds, and other passerine birds as a result of construction and operation of roadways is of concern for projects within or adjacent to suitable habitat. An analysis of peer-reviewed literature indicates the complexity of determining the effect of noise on avian species, including that from roadway projects. This is exemplified by several studies that show positive, neutral, and/or negative effects for specific avian species. Based on the available literature, assumptions, and limitations of studies completed, a review of the ecological and biological characteristics of passerine species studied and those known to occur, an impact assessment methodology was identified and applied to a proposed roadway project adjacent to grassland bird habitat. An area of Potential Indirect Noise Impact was identified, and additional analysis was conducted using population capacity, habitat requirement, nest-effect, and masking analysis. To assess the potential for masking, absolute threshold and critical ratio of avian species was compared to approximated noise levels from build and no-build conditions within suitable habitat. This analysis provided a basis for coordination with interested stakeholders and identification of avoidance, minimization, and mitigation options for the proposed roadway.
Terrestrial Wildlife and Ecosystem Interactions with Transportation