(Undated) -- Illinois is an important stop on the journey for billions of migratory birds making their way from South America to the boreal forest in Canada. The forest is referred to as “North America’s bird nursery," and a report released today (Monday) by the Boreal Songbird Initiative and Ducks Unlimited suggests that to protect the birds, at least half of the boreal forest must be protected from industrial development. Tom Clay with the Illinois Audubon Society explains. Clay says boreal birds are a valuable resource for Illinois, helping create a balanced ecosystem by pollinating plants, redistributing nutrients, and controlling pests. According to the report, birds are also big business, and in 2013, bird-watching trips and equipment generated more than 40-billion dollars in revenue nationwide.