The public continues to raise concern over the possible effects of noise resulting from military low-altitude aircraft. Even though some research has been accomplished in this technical area, conclusive results as to the effects of aircraft noise have not been documented for many types of animals. The Air Force has developed, through meta-analysis, an interim dose-response model to predict the effects of aircraft noise on raptors, but it has not been tested fully.

This research examined the problem and tested the Air Force model. This advanced technology research has been inserted into the latest version of the Assessment System for Aircraft Noise (ASAN) model for Air Force and Department of Defense-wide use in environmental impact analyses.

The first project task developed a study protocol in cooperation with the National Biological Service, University of Alaska Fairbanks Cooperative Fish and Wildlife Research Unit. The protocol addressed the effects of military aircraft overflights on raptor populations and included such factors as habitation, prey abundance, and changes in parental behavior. The second task was designed to make observations of behaviors and responses of nesting raptors during aircraft overflights. The effects of aircraft overflight noise on threatened and endangered species then were addressed using the protocol developed in task one, concentrating on the Peregrine Falcon (Falco Peregrinus Anatum). The final task involved making alterations to the current dose-response model for Air Force use and inserting the model into the ASAN model in FY 1998.

The project has developed a defense-unique ANM for noise data collection to assess noise exposure levels accurately. Approximately 127 of these monitors were deployed at experimental and control sites to gather quantitative noise data on the overflights over a 3-year period. The field teams made routine behavioral observations at both experimental and control sites and recorded the behavioral responses of the birds to jet aircraft overflights. The effort benefitted from some of the best "worst-case" scenarios on a limited number of occasions, thanks to the cooperation and support provided by the 11th Air Force. This project was completed in FY 1997.

In furthering our understanding of the effects of military aircraft overflights on the environment, this project accomplished the following: (1) enhanced our management tools for monitoring effects, (2) obtained valuable baseline data not previously obtained (past information is anecdotal in nature), and (3) improved the capability to predict noise effects on raptors. Researchers developed a defense-unique animal noise monitor (ANM) for remote noise data collection to assess noise exposure levels accurately. They also developed an interim dose-response model for raptors that will be validated or updated, depending upon the results of this effort. This updated model has been incorporated into the ASAN model, which will assist environmental planners greatly in conducting environmental impact analyses, developing timely environmental planning documents, and addressing concerns raised by the general public. These integrated resource management techniques will minimize potential noise impacts of aircraft operations on threatened and endangered raptors while maintaining mission readiness.