Mute swans are beautiful, but deadly
Submitted by Ted Williams on Mon, 04/03/2006 - 10:45.
Mute swans are beautiful, but deadly By KAY CHARTER Special to the Record-Eagle How would we react if we opened our morning newspaper to find a headline that read as follows: "Nests of endangered and threatened birds destroyed" Without a doubt, most of us would want to hunt down the culprits and mete out serious punishments. We absolutely would do everything in our power to make certain it never happened again. The sad reality is that this actually did happen in Chesapeake Bay, where nesting populations of endangered least terns and threatened black skimmers were not only disturbed, they have actually been eliminated by mute swans. With its wings arched elegantly over its back, and its neck held in a graceful curve, the mute swan is one of the most beautiful of all waterfowl as it moves silently across the water. But this bird is not native to North America. It is an alien species from Northern Europe and parts of Asia. It was introduced in this country when it was brought in as an ornamental species for parks, zoos and private estates. As with most successful non-native species this one didn't just survive and reproduce. It thrived, its population exploded, and it is now doing significant damage where it occurs. Mute swans reach sexual maturity at about three years of age and can live 25 years or longer. With each pair raising four to five cygnets (young) annually, it's easy to see how local populations increase exponentially. In the troubled Chesapeake Bay region, this species grew from five individuals in the early 1960s to more than 4,000 by 2002. Breeding mute pairs aggressively defend their nests and young against all comers, using their powerful wings and strong bills to drive away any other waterfowl. They outcompete endangered native trumpeter swans for breeding sites and food resources. They adversely impact numerous native species, including loons, ducks, geese and migrating tundra swans. They have even been known to displace or kill species that have entered their nesting areas, and they have a deleterious impact on the beds of native aquatic plants upon which native water birds feed. In high densities, they have overgrazed wetland vegetation to the point that the carrying capacity of the ecosystem has been reduced. It is for these reasons that groups as diverse as the Wisconsin Society for Ornithology, the Migratory Committee of the Conservation Congress, and the Wisconsin Wetlands Association are calling for the elimination — or at least reduction — in mute swan populations. Some states, including Michigan and Wisconsin, are actively trying to restore populations of native trumpeter swans. Without the control of mutes, however, these programs may ultimately fail. As long as the mute population growth goes unchecked, threatened species such as loons will have ever greater difficulties finding suitable — and safe — nesting sites. When asked about the presence of mute swans in Chesapeake Bay, Dr. Greg Butcher, Director of Bird Conservation for National Audubon said, "I strongly believe that the Chesapeake Bay, given its poor health, can only host one species of swan, and that the swan it should host is tundra." This issue is a very sticky wicket for state and federal wildlife management personnel. These swans are incredibly popular birds. They are handsome, and they are immortalized in literature and music as symbols of love, purity and fidelity — never mind that they do not always mate for life and that they often stray outside their pair bonds. Because of their popularity, efforts to control their numbers are inevitably met with angry outcries, protests and sometimes lawsuits. Even oiling the eggs, which prevents development and hatching, has been opposed. At an awards banquet in Lansing last month, I sat next to a DNR wildlife biologist who told me that efforts to restore trumpeter swans to Grand Traverse Bay were abandoned because of the mutes. Those who take up the banner on behalf of mute swans must ask themselves if protecting them is worth the prospect of giving up the loons, least terns, black skimmers, trumpeter swans and other waterfowl that are negatively impacted by them. Just as purple loosestrife and phragmites choke wetland ecosystems and autumn olive and spotted knapweed degrade upland habitats, these beautiful and elegant birds place an unacceptably heavy burden on native North American environments where they now occur. - 30 - Kay Charter is executive director of Saving Birds Thru Habitat, an organization dedicated to teaching people how to help migrating birds whose populations are declining.