a) Extend what is known about masking effectiveness of traffic noise on the vocalizations of birds by conducting behavioral tests with a wider range of individual and species.  It should be noted that precise definition of the questions and issues of the effects of highway noise on birds should be developed with the guidance of individuals who are expert on avian endocrinology and the literature on this topic.
b) Assemble current data or generate new data on vocalizations of endangered species including types, levels, preferred singing location preferences, habitat characteristics, territory size, effect of habitat characteristics on vocalization and noise transmission. This will allow precise modeling of the masking effect of traffic noise acoustic communication (high priority).
c) Obtain ABR measures of hearing (audiogram) and masking (critical ratios) in endangered species to determine how well they conform to the emerging model of masking of vocalizations by noise which, to date, is based primarily on laboratory species of birds (high priority).
d) Develop a generalized quantitative model for estimating communication distance based on masking data, habitat characteristics, territory size, the bird’s singing position preferences, and different traffic noise profiles (high priority).