Last spring, flooding destroyed 19 percent of trumpeter swan nests in Iowa. Then in the fall many of the juveniles, or cygnets, died from drought.
Iowa Department of Natural Resources wildlife research technician Dave Hoffman says modification of Iowa’s watershed causes this severe weather.
“Wetlands…act as sponges to clean and hold the water in the spring, but also…hold the water in the fall (to) provide the moisture we need.”
In fact, Iowa’s lost over 98 percent of its wetlands, or 2.5 million acres. “There are consequences when Mother Nature loses over 98 percent of her kidney functions…or flood control. How often do we have our 500-year floods?”
Trumpeter swans—the largest waterfowl in North America—disappeared from Iowa by the late 1880s. For two decades, the Iowa DNR’s worked to reestablish trumpeter swans to the state and at last count 48 mated-pairs resided in Iowa.
While 2013 was not a great year for the birds, northern Iowa’s population is nearing sustainable numbers. Now the DNR’s shifting attentions to introducing trumpeter swans in Iowa’s southern counties.
Last week Hoffman released nine trumpeter swans in southwest Iowa; five at Lake Icaria in Adams County and four at Union County’s Summit Lake.
Adams County Conservation Board park officer Travis Paul says that a 2005 rehab of Icaria, which was overrun by invasive species, made the swans' release possible.
“Part of that renovation was the construction of a large wetland," says Paul. "And when that wetland’s full, its 50-60 acres of water that is perfect shallow water...good for aquatic plants, food for filtering those nutrients and sediment from our water.”
He adds that in addition to swans, he regularly sees ducks, geese, pelicans, great blue herons, egrets and osprey around the lake.
In time and with efforts similar to those at Icaria, trumpeter swans could reside in all of Iowa's 99 counties.