Initiated in 1995, the Wisconsin Breeding Bird Atlas (WBBA) is an on-going project to document all bird species breeding in the state of Wisconsin. A project of the Wisconsin Society for Ornithology, WBBA documents the presence and breeding status of bird species detected within a selected 5km x 5km area, as well as (optionally) the estimated abundance of the species and the type of habitat in which it was detected. The results of this ambitious initiative are now available in the form of online Species Distribution Maps and multiple species summaries. While not all maps have been error-checked, these color maps offer detailed images showing confirmed and probable breeding locations for Wisconsin's several hundred species of breeding birds. In addition to the maps, the site provides a section on WBBA methods, numerous bird identification images, and a Casual Observation Form. A select list of links (to other states's Breeding Bird Atlas projects) rounds out the site.