A special task force has recommended that Maryland maintain some population of nonnative mute swans in the Bay, while establishing specific “swan free zones” to protect underwater grass beds, rare species and other sensitive sites,

The task force was appointed two years ago to study the issue after the killing of mute swans to protect the state’s only skimmer nesting site sparked an outcry.

Mute swans are natives of Asia, but the large beautiful birds which inspired Tchaikovsky’s “Swan Lake,” were brought to the United States to adorn private ponds. In 1962, five of the black-faced, orange-billed birds escaped from captivity into the Miles River. Since then, their population has grown to about 4,000.

Numbers of mute swans in the Bay have doubled since 1996. And the birds, once mainly confined to Maryland’s portion of the Bay, have been pressing into Virginia as well. DNR biologists say the population could double again within four years.

With their growing numbers, concern has risen that they could compete for habitat and resources with natives species, such as tundra swans, colonial wading birds and others.

The population is growing rapidly in part because it stays in the Bay all year and does not face the migration stress of native species. That also means the swans chew up underwater beds of Bay grasses all year, not just during the winter like other waterfowl.

Despite potential threats, the task force concluded that mute swans are “beautiful and pleasing to many Maryland residents” and that some population should be maintained for public enjoyment. It did not recommend a specific population level.

It also recommended the continuation of egg addling programs on public and — with permission — on private lands to prevent eggs from hatching. It also said problem swans could be relocated to other areas, and suggested that sterilization procedures may also be possible in the future.

The task force recommended that “swan free zones” should be established either seasonally, or year round, to prevent conflicts with other species that use similar habitats such as sandy beaches, and to protect resources such as underwater grass beds.

Possible ways to protect areas from swans could include fencing, and harassment, although the report said more research is needed on the issue. The task force suggested that as a last resort, lethal measures could be used to control swans within “swan free zones,” but that other measures should be exhausted first.

It recommended educational efforts for shoreline landowners, who are sometimes confronted by aggressive nesting mute swans. Landowners should be given information about fencing, addling eggs and managing conflicts, as well as be encouraged to not feed the swans.

The task force recommended that mute swans continue to be classified as “wetland game birds” but that no hunting season should be set in the foreseeable future. It also said regulations should be developed regarding the captivity, sale, transport, import and breeding of the birds.

The task force report is available for public review on the DNR’s web site at: www.dnr.state.md.us/wildlife/

After reviewing public comments, the state will finalize a mute swan management plan later this spring.