HOUGHTON - A proposed amendment to Michigan wildlife conservation regulations will give the state Department of Natural Resources and Environment increased leeway to deal with management of the mute swan.
However, lethal management of the bird that the DNRE considers non-native and a potential threat to Michigan ecosystems has proven unpopular in the past and the rule already has some wildlife activists up in arms.
"Mute swan populations are still quite low in the Upper Peninsula, but we do get more and more reports of sighting each year," said Barb Avers, DNRE waterfowl and wetland specialist.
The change in regulations, which is slated for a vote before the state's Natural Resources Commission Feb. 10, prohibits the possession and rehabilitation of live wild mute swans and establishes short- and long-term goals for controlling their population in Michigan.
The mute swan, which has an orange bill with a pronounced knob on the top, is considered by the DNRE to be a non-native species imported from Europe in the 19th century for their aesthetic qualities. The trumpeter swan, which is native to North America, has a black bill that tapers evenly.
Avers said the major reasons the DNRE seeks to manage mute swan numbers are threefold: first, the birds eat several pounds of aquatic vegetation daily and can damage ecosystems; second, they are aggressive toward native waterfowl species like trumpeter swans and common loons; and third, they can be aggressive to humans. Changes to the policy were crafted with the advice of 16 agencies (including the Audubon Society) over the summer.
At a glance
The mute swan is one of the world's heaviest and largest flying birds, weighing about 20 (females)?to 26 (males)?pounds. It has an orange bill with a pronounced knob, while the native trumpeter swan's bill is black and evenly tapered. Though it's called 'mute,' this type of swan does vocalize, just less than other swan species. Most wildlife agencies believe it was imported from Europe in the 19th century, unlike trumpeters, which they consider native.
DNRE officials estimate 15,500 swans live in the state, mostly in the southern half of Lower Michigan, and are growing at a rate of nine to 10 percent annually.
Wildlife biologist Bill Scullon of the DNRE's Baraga office said he has observed roughly a half-dozen at the head of Keweenaw Bay.
"Once they become established in an area, they slowly build up, then they hit a point where they begin to expand rapidly," he said.
The DNRE's intent is first to bring population growth to zero, then reduce the state count to about 2,000 by 2030. They also want to remove all mute swans on DNRE lands.
"We're managing these areas for native wildlife species," Avers said.
However, activists including bird rehabilitators and the Humane Society of the United States, contest many of the DNR's claims, believing that the birds could have migrated naturally from Europe via the Arctic, and that their purported impact on aquatic ecosystems and other species has been overstated.
The DNR has attempted to control the population through non-lethal means, such as the destruction of mute swan eggs and nests, but Avers said that effort just hasn't kept up with the birds' population growth.
"You've got to destroy an enormous number of nests and eggs to really make an impact," she said.
A small population of mute swans exists in Delta County on Little Bay de Noc. In 2008, DNR personnel shot two Bay de Noc swans as part of a control effort, which triggered a sizable public outcry from residents who enjoyed seeing the swans on the bay. DNR officials there now take what they call a 'stand-back-and-watch approach' to the issue.