Frequently Asked Questions about Maryland's Mute Swan Management Policy

NOAA

This family of swans calls the Chesapeake Bay home.

1. What are mute swans?
2. Where are mute swans found?
3. What is the Maryland Department of Natural Resource's plan for mute swan management?
4. Are mute swan populations a threat to the Chesapeake Bay?
5. Why does The HSUS oppose the DNR's management plan?
6. What is The HSUS doing to protect mute swans, and why have we asked Governor O'Malley to intervene?
7. Is The Humane Society of the United States prepared to work with DNR?

1. What are mute swans?

Mute swans are a species of white swan (Cygnus olor) with a distinctive red bill. These spectacular birds can reach up to five feet tall and can weigh up to 30 pounds. Pairs of swans tend nests of 5-8 eggs in the spring. The "ugly ducklings" (or cygnets) hatch within 38 days and stay with their parents for about a year. In the wild, pairs tend to mate for life, and individuals may live for nearly 20 years.

2. Where are mute swans found?

Mute swans reside primarily in estuarine environments with smaller numbers on inland lakes and ponds. Mute swans can be found up and down the eastern seaboard and as far west as Montana and Utah.

There is conflicting evidence about whether mute swans are native to the North American continent or were introduced into the United States in the 1800s for aesthetic enjoyment. (Some posit that native populations were supplemented by non-native birds.) Regardless, they are now a naturalized part of the environment.

3. What is the Maryland Department of Natural Resource's plan for mute swan management?

For the last four years, over the vehement objections of its citizens, the Maryland Department of Natural Resources (DNR) has slaughtered adults and cygnets in the Chesapeake Bay, claiming it was necessary to stop the birds from eating Submerged Aquatic Vegetation (SAV), which is their natural food. As of 2002, there were approximately 3,624 mute swans in the state. In 2005 and 2006, the DNR killed approximately 2,700 swans. The DNR has not reported how many swans it killed in 2007 or how many it has killed so far this summer. According to eyewitnesses, swans are being killed randomly without regard even to alleged "damage."

4. Are mute swan populations a threat to the Chesapeake Bay?

No. Although mute swans eat some SAV, they are in no way a threat to the health of the Chesapeake Bay ecosystem. The Chesapeake Bay is a dynamic ecosystem stressed by the effects of pollution, turbidity and the catastrophic effects of rampant development of adjoining land (contamination with pesticides, fertilizers, sewage, septic algae, etc.). But the Chesapeake Bay has always been host to huge populations of various species of waterfowl including geese and swans and ducks, most of whom eat the underwater vegetation. From a macro perspective, the relatively recent arrival of a few thousand mute swans is just a minor—and incredibly beautiful—variation in the annual species composition of waterfowl in the bay. 

The DNR has alleged concerns regarding the amount of SAV mute swans eat. Of course, mute swans do eat vegetation; however, this is a minuscule problem compared to the waste run-off of farms into the Bay, water pollution, turbidity caused by boat propellers and wakes, and physical damage to aquatic vegetation from boats. Moreover, as of 2006, the Chesapeake Bay in Maryland contained 32,586 acres of aquatic vegetation. There are now probably fewer—perhaps far fewer—than 1,000 left in Maryland's Chesapeake Bay. It is preposterous to suggest that a few thousand swans can have more than an incidental localized effect on aquatic vegetation.

Furthermore, aquatic vegetation is adapted to being eaten by aquatic herbivores such as swans. To remove these birds now that they have become established will disrupt the food webs of which they have become a part. The fact is that the DNR is scapegoating mute swans to cloak its inability to control the real threats to the Bay. 

5. Why does The HSUS oppose the DNR's management plan?

The DNR's lethal management plan arbitrarily targets a beautiful element of the Chesapeake Bay ecosystem, causing the unnecessary and inhumane killing of these animals, reportedly using cruel methods.

The state cannot support its claims that mute swans are having a significant effect on the overall quality or quantity of SAV in the Bay with any data. Studies have shown that mute swans do, in fact, eat SAV, but no study to date has proven a link between SAV loss in the Bay and localized mute swan activity. In its 2003 mute swan management plan, the DNR admitted that "data on the reduction of SAV by mute swans is limited." Furthermore, the U.S. Fish and Wildlife Service has found that "it is unlikely that swans (or any other grazers) represent a threat serious enough to decimate the submerged aquatic plants throughout the Bay."

Pollution and increased sediments in the water, along with physical effects of boat propellers and major turbidity cause SAV loss, not mute swans or any other herbivore. Agricultural, municipal, and industrial run-off; increased development; channelization, and dredging all serve to degrade and destroy the delicate balance between water quality and substrate characteristics that foster the perpetuation of healthy SAV beds.

6. What is The HSUS doing to protect mute swans, and why has it asked Governor O'Malley to intervene?

When then-Governor Ehrlich’s administration first announced its swan-killing plan in 2003, The Fund for Animals (now an affiliate of The HSUS) filed suit on the grounds that the killing was not only unnecessary but also illegal under the National Environmental Policy Act (NEPA). This case was voluntarily dismissed when Maryland agreed to abstain from killing mute swans until it had prepared the Environmental Assessment required by NEPA.

After the EA was completed, the Ehrlich Administration renewed its efforts to begin killing mute swans, and The HSUS went back to the court, asking it to stop the state from killing any mute swans on grounds that the swans were protected under the Migratory Bird Treaty Act (MBTA). The court granted a preliminary injunction in The HSUS's favor, and the state withdrew all pending permits to kill mute swans and agreed not to issue new permits to kill mute swans until it had conducted a new environmental review consistent with both NEPA and the MBTA.

Unfortunately, on Dec. 8, 2004, Congress enacted the Migratory Bird Treaty Reform Act of 2004, which limited the MBTA's protections to native migratory bird species. Although The HSUS continues to maintain that mute swans are protected by law, the DNR is now allowed—but certainly not required—to kill mute swans at will.

However, since the DNR first announced its swan-killing plan, The HSUS has offered to help implement a non-lethal management plan such as egg-addling that would control any significant damage caused by mute swans while limiting population growth. The HSUS has been involved in egg-addling efforts which have successfully and humanely resolved conflicts with waterfowl populations in problem areas in several states and has offered to help Maryland officials humanely reduce the mute swan population through an egg-addling program, in lieu of the proposed wholesale slaughter. Although state officials have previously acknowledged that addling the eggs of mute swans may slow or reduce Maryland’s population, they now refuse to rely on this humane approach and are intent on killing swans.

7. Is The HSUS prepared to work with the DNR?

The HSUS is eager to work with the state of Maryland to resolve the situation using humane methods. We have significant experience in implementing non-lethal wildlife problem resolution techniques and have participated actively in non-lethal management of Canada goose populations in urban areas across the nation. We also direct the first nationally recognized commercial operation to implement Humane Wildlife Solutions to solve wildlife problems in urban areas. We have offered all of our proven expertise to the DNR and are seeking a cooperative relationship to protect the majestic mute swans of the Chesapeake Bay and humanely mitigate any perceived or real conflicts that may occur. The agency, unfortunately, has not been willing to change course from its lethal control program, although our offer of cooperation still stands.

Updated August 28, 2008.