A quintessential urban estuary is the lower Passaic River in northeastern New Jersey, USA. This system is environmentally degraded and its ecosystem is functionally limited. Birds in this river are of particular interest for ecological assessment and environmental management because they are conspicuous, ecologically important, and their habitat requirements encompass the full range of ecosystems associated with the estuary. In this article, we present the results of a 1-year seasonal bird survey of the lower 6 miles of the Passaic River. We contrast our survey results with those from other waterways in the region that have stressor issues similar to the Passaic (i e, contaminants, pathogens, physical disturbance, etc), but which have substantially more wetlands habitat available for birds (i e, fewer habitat constraints). Our objective was to evaluate the influence of habitat availability or constraints on bird use in such systems. The results of our survey and comparison to conditions of other regional waterways demonstrate that the lack of wetland and associated shoreline habitat in the lower Passaic River is likely the primary constraint on bird use of the system. Future investigations of individual stressors in this region should identify the habitat constraints in the decision matrix for judging management options.
