The San Pedro River's riparian forest is a regionally important area for breeding and migrating birds. Many land managers and restoration ecologists see the re-establishment of beaver as a potentially invaluable and low-cost tool for the restoration of riparian environments. In 1999, the Bureau of Land Management, in cooperation with the Arizona Game and Fish Department, re-introduced beaver in the San Pedro Riparian National Conservation Area, resulting in their successful establishment. Because diversity and density of breeding birds increases with volume and density of vegetation, bird communities will likely be influenced by beaver. Effective management of riparian systems requires that we understand how beaver activity affects bird communities. In this study, we will quantify the influence of beaver on bird community composition on the San Pedro, and, for select priority bird species, determine differences in density and nest success among areas with and without beaver. Over the course of this project we will (1) compare density, nest success, species richness, and diversity of bird species found in areas influenced by beaver as compared to those without beavers at multiple scales in the San Pedro Riparian National Conservation Area; (2) describe influence of beaver on vegetation and habitat structure that may explain bird community dynamics; and (3) inform land managers and restoration ecologists regarding potential influence of beaver re-introduction projects on local bird communities, especially in riparian ecosystems of the southwest.