Decades of Wood Duck Banding Used as a Management Tool
Every summer while wood duck hatchlings are making their way to a nearby stream, river, pond or lake, a local Illinois Department of Natural Resources (IDNR) District Wildlife Biologist (DWB) isn’t too far behind. During this time of year DWBs begin to prepare sites with the goal of trapping and leg banding as many of these birds as possible.
Wood ducks (Aix sponsa) are one of 43 waterfowl species nesting in North America and are one of seven species that nest in cavities. These birds are the most abundant species of waterfowl nesting in Illinois and have been documented nesting in all 102 Illinois counties. Females begin selecting mates between October and February and initiate egg laying between March and May. An average clutch size is 12 eggs and incubation ranges between 28 and 37 days. Hens exhibit a high level of nest site fidelity, will regularly initiate a second nest if the first is destroyed, and have been known to produce two broods in a single nesting season. The precocial ducklings usually leave the nest within 24 hours after hatching. The hen-brood bond usually lasts 6 weeks. The young have replaced enough downy plumage with feathers to be capable of flight between weeks 8 and 10.
Waterfowl Banding History and Importance
Why do biologists trap and band wood ducks? The process of trapping and banding waterfowl in Illinois dates back before the 1920s, but really gained steam when Fredrick Lincoln, head of the U.S. Bureau of Biological Survey bird banding office in Washington, D.C., banded 1,667 mallards in the Sangamon bottoms in 1922. Lincoln’s banding effort in Illinois was considered the first large-scale trapping of waterfowl in the United States.
Waterfowl research in the Illinois River bottoms increased in the late 1920s in response to lower population levels and weather conditions. In 1938, Arthur Hawkins and Frank Bellrose chose to focus their research on wood ducks since they were abundant and breed in Illinois. A year later the Illinois Natural History Survey (INHS) began its waterfowl banding program when J. Anderson came on board.
The first continental migratory gamebird banding plan was prepared by the United States Fish and Wildlife Service (USFWS) and Canada Wildlife Service in 1959. The plan provided guidance to states on banding goals and distribution for priority species of waterfowl. The Mississippi Flyway states were given a goal of banding 500 wood ducks each year, but this objective increased to 1,000 per state in 1964. Banding goals and protocols for wood ducks have been revised several times since the mid-1960s as new information on population dynamics became available, statistical and banding reporting methods improved, and as management needs changed.
Since the 1980s, wood duck banding levels generally have been set to provide the minimum amount of information necessary to calculate reliable survival and harvest rate estimates for different populations, age and sex classes. On average, IDNR biologists have captured and banded approximately 2,300 wood ducks per year since 1989. Banding remains the best tool IDNR biologists can use to monitor wood duck population since there isn’t a better method available to count this species. Unlike several other species of waterfowl that that typically flock in open agriculture fields or open water, wood ducks tend to congregate in flooded timber or brushy swamps making these birds extremely difficult or impossible to count when conducting aerial surveys.
The need and importance of waterfowl banding as a tool for management decisions was reinforced in 2008 when the USFWS increased the wood duck daily bag limit to three because of the accurate and precise estimates of annual survival and harvest rates from successful banding programs.
IDNR biologists usually use corn-baited Y-traps, swim-in traps or rocket nets, although some biologists utilize an airboat, night-light and nets to capture wood ducks at night. At Union County State Fish and Wildlife Area, the trap constructed in the early 1950s, and used by George Arthur when he began banding waterfowl in southern Illinois, remains in operation.
Once a successful catch is made, biologists begin by securing the wood ducks, ensuring that none are at risk of injuring themselves, then carefully remove them from their cages and examine each one to determine sex and age. An aluminum band with a unique nine-digit code is placed on the leg, data is recorded and the bird is released.
The responsibility rests with hunters to assist in estimating survival and migration patterns by reporting all recovered bands by going to REPORTBAND.gov. Even old bands with only a phone-in reporting inscription can be reported online.
The information essential to monitoring wood duck populations has the potential of being record breaking. For example, Illinois currently holds a record for one of the oldest wood duck bands recovered—a wood duck banded in 1964 was found in Wisconsin in 1977, 13 years and 4 months later.
Kenneth Delahunt is an Illinois Department of Natural Resources District Biologist in Region 5, southern Illinois. He earned both his B.S. and M.S. in Zoology from Southern Illinois University—Carbondale. Previously, Delahunt worked as a Wildlife Biologist for USDA-Wildlife Services.