Will revolutionary new leg bands significantly expand our understanding of North American ducks? This is our hope. The bands, affixed to day-old ducklings, are designed to allow us to learn more about duckling mortality, post-hatching dispersal and migration.

The new bands are oval-shaped, narrow (5-6 mm in width, about half the width of a conventional wood-duck size aluminum leg band) and correspond to the shape and maximum size of the leg (tarsus) of adult ducks. The inside surface of the band is covered with a thin layer of plasticine, a soft material widely used as a modeling clay. Plasticine prevents the relatively large bands from slipping off the small tarsus of ducklings. It gradually wears out as the leg grows, so the band fits perfectly and remains on the leg during the rest of the adult duck’s life. Importantly, the bands are detected just as easily as regular leg bands by both biologists and hunters.

I participated in the refinement of this banding technique during the 1960s and early 1970s in Latvia (Eastern Europe) and introduced these bands in the United States in 1993. The primary problem involved developing a band filler that (1) prevented band loss during the first two weeks after the hatch when ducklings are still small, and (2) did not cause leg injuries during the post-fledging period.

We tested more than 10 different fillers (modeling clays, plastic and rubber foams, etc.) on day-old ducklings in Missouri’s Mingo Swamp and elsewhere. This research, coupled with five years of experimental banding in Missouri, Kentucky, and Mississippi, prompted the U.S. Bird Banding Laboratory (BBL) in 1998 to approve the bands. All duckling bands currently used in North America have the BBL toll-free number inscription (CALL 800-327-BAND) on the band.

Prior to the development of these plasticine bands, survival studies in North American waterfowl primarily depended on the use of conventional leg bands. These aluminum bands normally are attached to young just before they reach flight stage, on breeding or molting adults in summer, or on adults or subadults during winter. North American biologists also have marked day-old ducklings with web tags for more than three decades, but these tiny tags are rarely reported because hunters generally fail to notice them.

The new plasticine-filled leg bands were developed and successfully used by a team of dedicated waterfowl biologists in Latvia in early 1960s. The two individuals who conceived the idea and contributed most to the development of this technique were G. Lejins and V. Klimpins. Approximately 100,000 day-old ducklings were banded in Latvia during 1961-2004. This banding technique gradually expanded to many other European countries but was never used in North America before 1993.

The plasticine-filled leg bands for day-old ducklings currently are used for different banding projects across North America. In Missouri’s Mingo Swamp, we used the bands to mark more than 11,600 day-old wood ducks and hooded mergansers from 1998-2004, and have received more than 500 returns from hunters.

There are two primary reasons for leg band studies of ducklings. First, estimates produced by most current banding studies do not include the first two to four weeks following hatching when most mortality occurs. Survival estimates based on studies of ducklings banded on the day of hatch would include this early period. Second, using plasticine-filled leg bands may also answer questions about the exact location where young birds are produced, and thus there is a potential to learn much more about post-hatching dispersal, migrations, and wintering of young birds. This is especially important for many waterfowl species that are very difficult to capture during the period between nest exodus and first breeding. For many species with delayed maturity this non-breeding period can last for two to three years.

For example, large-scale banding of day-old hooded merganser ducklings in Mingo Swamp has provided new information on unusual long distance natal dispersal movements. Fifty-four mergansers (27 percent of all recoveries) banded at hatch were later shot by hunters more than 400 miles north of the Mingo Swamp study area. The recovery locations of these 54 birds included Iowa (1), Nebraska (1), South Dakota (3), North Dakota (9), Michigan (7), Minnesota (27), Wisconsin (5), and Manitoba, Canada (1).

Unlike wood ducks (see below), 54 percent of the hooded mergansers that moved north were recovered during the first hunting season, suggesting that more than half locally hatched mergansers moved north immediately after they fledged. The true proportion of juveniles that moved north during the first fall was probably much higher because not all long-distance dispersers were shot during the first hunting season. Northward movements of juveniles after fledging are energetically costly, because these birds must then migrate southward and overfly their natal wetlands before reaching their Gulf Coast wintering areas.

The difference in long-distance northward movements between hooded mergansers and wood ducks hatched at Mingo is striking. The percentage of recoveries showing long-distance dispersal movements was much larger for hooded mergansers than for wood ducks (27 percent vs. 5 percent). In addition, most mergansers moved north during the first autumn following hatching, but no recoveries of young wood ducks were recorded from these distant northern areas during the same time period.

The observed difference in long-distance northward movements probably can be explained by a different population status of the two species in Mingo Swamp. The local merganser population was gradually expanding during the study period (1996-2004) while the wood duck population remained relatively stable during the same period.

The northward movements of hooded mergansers are poorly understood. We need more information on this behavior. For example, were these dispersers males or females? Why did the young mergansers migrate northward mostly during the first fall immediately after fledging?

Plasticine bands can identify these unusual behaviors for all species and guide us in directing future research so that we can better manage our waterfowl.