The birds of Illinois and their particular habitats are explored in this guide which is a part of a series of Nature Discovery publications. The materials are designed to directly supplement the natural science curricula and to complement other subject areas including social studies, language arts, music, and art. The program is formated for students in a self-directed and participatory manner. The chapter introductions and individual exercises address the students directly. Exercises appropriate for indoor use bear a "Classroom Discovery" emblem, while outdoor activities are designated with an "Outdoor Discovery" emblem. A system of tallying points is offered at the conclusion of the activities. A teachers guide is provided and contains suggestions for each of the five student chapters. The themes of these chapters are: (1) preparing a discovery manual (focusing on the terms and concepts basic to the study of avian ecology); (2) building bird field guides (examining the processes of bird identification and habitat adaptation); (3) nature sleuthwork (including simulated and actual field investigations); (4) making environmental decisions (reviewing problems involving birds and other wildlife); and (5) nature discovery poster (providing a song about birds, a bird model, and a plan for constructing a nesting box). Pen and ink illustrations are offered throughout the document. (ML)