Founded by professional ornithologists in December 1912, Chicago Ornithological Society is engaged in promoting public appreciation of birds and the restoration of bird habitat in the Chicago region. Everyone is welcome to join us, whether you are a beginner, an experienced birder, or have an interest in conservation and restoration of bird habitat.

COS is a also founding member of Bird Conservation Network, a coalition of 21 organizations (Audubon chapters, bird clubs, and conservation organizations) sharing an interest in the conservation of birds.

Our mission is to promote public awareness, knowledge, appreciation and enjoyment of birds and their habitat in the Chicago region.