Bird populations were censused on a 50-m wide, wooded expressway median and a similar tract not so bordered. Vegetation was compared, and the 2 sites were found to be alike in the habitat they offered to bird life. Noise levels at the median site were substantial, while the control site, far from traffic, was relatively quiet. Species and numbers of birds on the median site were about half that of the control. The species present on the control site but absent from the median were largely forest species while the median site contained primarily species of wide ecological amplitude, all but 1 of which were also present on the control. The median acted as an insular environment which was large enough for use as a nesting territory by some species but probably insufficient for others. Disturbance from traffic was probably another factor making the median unsuitable for nesting habitat, since it was large enough to support a number of species which were absent there but present in the surrounding woodland. The birds occurring on both sites used area outside of the strips as territory; accordingly, the suggestion is made that the species absent from the median were those unable to cross the highway to utilize adjacent land. A wider median of similar vegetation would therefore probably support a greater number of forest species.