Birds and the Mississippi River. Each day, birds must find food, water, shelter, and places offering refuge from predators. This becomes even more important during migration as birds are often moving through unfamiliar terrain with unknown risks. The Mississippi River valley--along with its rich diversity of habitats--provides birds with those important resources. It is little wonder then that this large, south-flowing river forms the core of one of North America's great flyways and offers birders wonderful opportunities to observe a wide variety of species.