The Wisconsin Society for Ornithology was organized in 1939 to encourage the study of Wisconsin birds. The aims have since expanded to emphasize all of the many enjoyable aspects of birding and to support the research and habitat protection necessary to preserve Wisconsin birdlife. WSO strives to alert members and the public to situations and practices that threaten Wisconsin's bird populations. Members include those who enjoy birds attracted to their homes by feeders and bird houses, those who pursue field study or bird banding as a hobby, and those who engage in ornithology professionally. Membership exceeds 1500 from across the United States and around the world.
The WSO publishes The Passenger Pigeon, a quarterly journal featuring a wide range of articles on Wisconsin birds, seasonal field sightings including Christmas, May and Big Day counts, and scientific research reports. Reports from birders throughout the state on unusual and interesting sightings and articles on all aspects of birding are included regularly.