Spring begins as ice on the river begins to break up and melt. Winter’s grip has not gone, but we know spring is on its way when the first red winged blackbird males return. There will begin a continuous flow of different species into and through the refuge. Each day offers something new. Birds are in their bright and colorful breeding plumage and the observant visitor can witness eons-old courtship rituals. Large flocks of mountain blue birds against the background of a late spring snow is a memorable sight. Bald eagles begin laying and incubating eggs in early March and will remain on the nest through inclement weather. Although some Canada geese, trumpeter swans, and mallards wintered here on open stretches of the river, new species of ducks begin to arrive in early March. Common goldeneyes and ring necked ducks arrive in numbers with aggressive courtship displays to watch. Canada geese and trumpeter swan pairs select and begin defending a nesting site from others of their kind. Next to arrive are widgeon, gadwalls, shovelers, green winged, blue winged, and cinnamon teal. The last of the ducks to arrive are ruddy ducks with their electric blue bills. Shorebird migration lasts from early April through mid-May. One of the last migratory “shows” goes little noticed. In May, secretive warblers move onto the Refuge to rest and feed on insects among the newly emerging leaves of narrow leaf cottonwood and other riparian vegetation. They have migrated here from some distance, a few as far as southern South America. One of the best places in Wyoming to find these warblers during spring migration is from Refuge Headquarters to the base of Fontenelle Dam.