Contact: Jonathon McKnight, Maryland Department of Natural Resources
ANNAPOLIS, MD (June 6, 2003) - The descendants of five pet mute swans that escaped from their Talbot County home in 1962 have reached a population of more than 4000 in the Chesapeake Bay region. Their aggressive behavior has led to the displacement of native birds from nesting and feeding areas and is devastating underwater grass beds. It is for these reasons that the Maryland Invasive Species Council (MISC) has named the mute swan to be June’s “Invader of the Month.”
Mute swans, a native of Asia, are the largest species of waterfowl in the Chesapeake Bay region and one of the world’s most aggressive bird species. Mute swans were responsible for driving the last remaining colony of Black Skimmers from the Chesapeake Bay and for eliminating important tern nesting habitats.
But it is the devastation of underwater grasses that the swan is having its greatest effect. Already reeling from decades of water quality degradation, this important aquatic ecosystem is now being devoured at an alarming rate by the Chesapeake’s burgeoning mute swan population. The current population eats an estimated 10.5 million pounds of aquatic grasses every year. Natural resource managers are afraid that without control of adult swans, this population-- which has doubled more than nine times in 40 years, will double again. If the population is allowed to double again, the level of consumption and disruption will rise accordingly.
Aquatic grasses are the base of most of the food chains in the Chesapeake estuary and many plants and animals depend upon them for survival, including many commercially important species. Native waterfowl graze the same grasses, but are only in the Chesapeake Bay region for over-wintering.
Because mute swans are in the Chesapeake year-round, they spend the summer eating the new plants that are critical for the re-establishment of aquatic grass beds. Grass bed restoration, a key component in the effort to restore the Chesapeake Bay, has been severely curtailed by mute swans, who can wipe out a restoration planting in a few days.
The Maryland Department of Natural Resources has developed a mute swan management plan which provides guidance to manage the species in Maryland through 2008. The plan can be viewed at: http://www.dnr.state.md.us/wildlife/Hunt_Trap/waterfowl/muteswans/
MISC hopes to raise public awareness about the problems with this and other invasive species through its “Invader of the Month” program. For more information about mute swans and other Invasive Species of Concern in Maryland, visit http://www.mdinvasivesp.org or call Jonathon McKnight, Maryland Department of Natural Resources at 410-260-8540.