The Boy Who Drew Birds is a free 20-page download from Homeschool Share — another one of their very nicely pulled-together resources.
Using the picture book biography The Boy Who Drew Birds: A Story of John James Audubon by Jacqueline Davies as a spine for the study, the unit covers history, geography, science, language arts, art and math.
The topics you will cover include Napoleon, France, Pennsylvania, caves, seasons, idioms, and, of course, birds.
Activities include map work, copywork, writing a letter, keeping a backyard bird lapbook, making a bird feeder, creating a mixed-media picture and keeping a nature journal. A bibliography provides more options for further research.