The Missouri River corridor is on the western edge of migration routes for many eastern warbler species. In synchrony with the tree buds opening in May and bugs emerging to forage on the new plant growth, the warblers arrive to feast on the abundance of insects. Some warblers are resting and refueling here as they continue their long journeys from their winter grounds in central and South America northward to their breeding grounds in the northern United States and the boreal forests of Canada.
Most of the warblers, especially the males, have bright yellow, orange, or sharply contrasting white and black plumages. While some species like the American Redstart will stay to breed in the wooded river corridors, many species such as the Magnolia Warbler will merely pause here on their way to their northern breeding grounds and again in early fall as they return to their wintering grounds.
Although brightly colored, warblers can be deceptively tricky to see among the foliage of tree canopies. To locate warblers, listen for their unique songs and calls and then watch for quick flashes of color as the warblers flit restlessly among the branches. Often warblers migrate together in mixed flocks so look closely as one tree may have several species foraging in it.