Some ducks return to the precise location where they nested the previous spring, while others return to the same wintering area year after year. The ability of migratory birds to find these specific locations after being away for several months is a form of navigation known as homing.
Homing rates vary among waterfowl species. For example, up to three-quarters of adult female canvasbacks return to the same pothole where they nested the previous year.
Cavity-nesting species like wood ducks, buffleheads, and goldeneyes also return at high rates to prior nesting sites. In contrast, blue-winged teal have one of the lowest homing rates of all ducks. Only 5 to 15 percent of female bluewings return to their former nesting grounds the next year.
Amazing Migration Facts
- Some Pacific brant migrate nonstop from a staging area in Alaska to their wintering grounds in Baja California—a journey of about 3,000 miles. The birds lose almost half their body weight in this 60- to 72-hour flight.
- Not all populations of a given species are migratory. About one-third of the wood ducks in the eastern United States and nearly three-fourths of the Pacific Flyway wood duck population are nonmigratory.
- Birds fly at varying altitudes during migration. Skeletons of pintails have been found at elevations of 16,000 feet on Mt. Everest, but most birds migrate at altitudes of between 500 and 2,000 feet.
- Mallards migrating at 55 miles per hour burn 1 gram of body fat for every four miles they fly.
- A mass migration of waterfowl—known as a grand passage—is often triggered by a severe winter storm. During one of these events in November 1995, so many ducks and geese were on the move that radar operators at several major midwestern airports couldn't distinguish flocks of waterfowl from airplanes.
Dr. J. Dale James is manager of conservation planning and Andi Cooper is a communications specialist at DU's Southern Regional Office in Ridgeland, Mississippi.