Encompassing 8,501-acres, the Two Rivers National Wildlife Refuge is one of five refuges in the Mark Twain National Wildlife Refuge Complex. The majority of the land protected is located near the confluence of the Illinois and Mississippi rivers. The refuge is managed for migratory birds, endangered species, and migratory fish and provides an important link in the chain of resting, feeding, and wintering areas for migratory species using the Mississippi Flyway, as well as important habitat for many resident wildlife species. Spring and fall are the ideal seasons to witness migrating waterfowl, shorebirds, wading birds, and songbirds as they move along the Mississippi Flyway. In the winter months, the migrating American Bald Eagles can often be found nesting in the Gilbert Lake Refuge or roosting and feeding near Swan Lake.