David R. Marks 

District Supervisor

USDA-APHIS Wildlife Services

Urbandale, Iowa

 

Human-Wildlife Conflicts

Mute swans (Cygnus olor, Figure 1) are an 

invasive species originally brought to the 

United States in the late 19th and early 

20th centuries for ornamental ponds and 

lakes, zoos and aviculture collections. 

Original populations were located in 

northeastern states along the Hudson 

Valley but have since expanded to several 

Midwestern states and portions of the 

western U.S. and Canada.

Mute swan damage includes competing 

with native waterfowl, destroying native 

plants, spreading disease, and colliding 

with aircraft. They are also considered a 

nuisance in some areas due to their 

abundant fecal droppings and 

aggressiveness towards people.

Natural Resources

Mute swans can impact ecosystems by 

foraging on native plants and competing 

with native species for food and habitat. 

Mute swans forage primarily on 

submerged aquatic vegetation, and each 

swan consumes 4 to 8 pounds of 

vegetation per day. While feeding, mute 

swans use their feet to expose plant 

shoots and roots for foraging, and to help 

dislodge food for cygnets (i.e., young 

swans). This damages aquatic substrates 

and vegetation surrounding preferred 

foods. Mute swans typically consume less 

than 50 percent of what they remove. 

Results from one study showed their diet 

overlaps considerably with many native

Wildlife Damage Management 

Technical Series

U.S. Department of Agriculture

Animal & Plant Health Inspection Service

Wildlife Services

February 2018 Mute Swans

Figure 1. Adult mute swan (Cygnus olor).

Quick Links

Human-Wildlife Conflicts 1

Damage Identification 3

Management Methods 3

Economics 8

Species Overview 8

Legal Status 11

Glossary & Key Words 12

Resources 13 

Appendix 14 
waterfowl species that overwinter in the lower Great Lakes 

or temporarily use the area during migration. 

Mute swans are known for their highly territorial behavior 

during their breeding season, and may compete with native 

wildlife for space and associated resources. Of particular 

concern are potential impacts on threatened and 

endangered species. During the breeding season, mute 

swans sometimes displace other native waterfowl from 

preferred nesting locations, and may kill adult and juvenile 

ducks and geese (Figure 2). During one incident in 

Maryland, a large molting flock of mute swans caused a 

colony of least terns (Sterna antillarum) and black 

skimmers (Rynchops niger) to abandon a nesting colony by 

trampling nests, eggs, and chicks. The mute swans also 

displaced nesting common terns (Sterna hirundo). In 2011 

in Michigan, a mute swan nest was found in the middle of 

a black tern (Chlidonias niger) colony that had previously 

supported approximately 54 black terns in 2009. Only a 

few black tern nests remained, approximately 30 to 40 

feet away from the swan nest. 

Agriculture

In some portions of the world, mute swans damage 

agricultural crops, such as wheat and oilseed rape. In the 

U.S., however, incidents of swan damage to crops are rare. 

Mute swans may serve as vectors or reservoirs for 

diseases of significance to agriculture, such as Newcastle 

disease and avian influenza. A 2014 study showed that 60 

percent and 45 percent of the mute swans sampled had 

been exposed to Newcastle disease virus and avian 

influenza virus, respectively.

Human Health and Safety

While the transmission of diseases or parasites from 

waterfowl to people has not been well documented, 

various studies indicate that the potential exists. In worst 

case scenarios, infections may be life-threatening for 

immunocompromised people. Diseases that potentially 

may be transmitted through mute swan feces to people 

include swimmer’s itch, salmonellosis, and E. coli

infections. However, scientists at the Centers for Disease 

Control and Prevention estimate the risk of such infections 

is low. Costs associated with disease issues and mute 

swans can be high and include the following:

 testing of water for coliform bacteria 

 regularly cleaning feces from beaches and other 

recreational areas

 lost revenue associated with recreational sites that are 

temporarily closed because of fecal contamination

 consultation with public health officials

 implementing nonlethal and lethal mute swan damage 

management methods

In addition to disease issues, mute swans also threaten air 

safety. Bird strikes usually kill birds and can damage 

aircraft, disrupt airport operations, and erode public 

confidence in the safety of air travel. Mute swan collisions 

with aircraft not only risk human safety, but also result in 

expensive damage to aircraft, loss of aircraft due to 

repairs, and monetary losses due to flight cancellations 

and delays. In the U.S. from 1994 to 2011, there were 

eight reported mute swan bird strikes. Although this 

number is low compared to other species, the size of mute 

swans makes them particularly hazardous to aircraft. 

In areas with high numbers of mute swans, attacks on 

people and pets have become more frequent. Mute swans 

defend their nests, nesting areas, and young from any 

Page 2 WDM Technical Series─Mute Swans

Figure 2. Mute swan showing aggression toward a mallard.
perceived threats, including people and pets. Birds that are 

fed by people may become aggressive in seeking food. 

Most of the aggressive behavior involves displaying 

dominant postures and making hissing noises, without 

making physical contact (called bluffing). However, mute 

swans are capable of inflicting bruises, sprains and bone 

fractures. In at least one case in Illinois, a mute swan 

attack resulted in a human fatality. A man in a kayak 

ventured too close to a mute swan nest; the swan attacked 

and caused the man to capsize the kayak. The man was 

not wearing a personal floatation device and witnesses 

reported the swan continued to attack as the man tried to 

keep his head above water. 

Nuisance

Most conflicts between mute swans and people affect 

people’s enjoyment of recreational sites or activities. 

People often cannot use and enjoy their own property, 

public parks and other areas because of aggressive swans 

or the accumulation of swan feces. Costs associated with 

mute swan nuisance problems include labor and 

disinfectants to clean and sanitize areas, loss of property 

use and resale value, loss of aesthetic value of aquatic 

vegetation in areas where mute swans nest, loss of 

customers or visitors fearful of swimming in waters with 

swan feces or of being attacked by aggressive swans and 

implementation of wildlife management methods. 

Damage Identification

Most mute swan damage is difficult to attribute to the 

species unless the birds are actually observed causing the 

damage. For instance, competition with other waterfowl for 

breeding or food resources may not be readily seen. 

Observable mute swan damage includes destruction of 

submerged and emergent aquatic vegetation. Mute swans 

typically consume only about 50 percent of the material 

they uproot or damage during feeding, therefore, remnant 

vegetation is often floating in areas where mute swans 

have fed. Although damage to submerged aquatic 

vegetation may be difficult to assess because it occurs 

underwater, it may become apparent as remnant 

vegetation accumulates along shorelines and beaches. 

Damage also may become visible during periods of lower 

water levels (Figure 3).

Damage to emergent vegetation typically occurs during the 

breeding season when swans are building their nests. 

Plants are used for the nest itself, and often large mats of 

uprooted vegetation can be found surrounding the nests 

(Figure 4). 

Mute swan feces can impact water quality, and land areas 

surrounding ponds and lakes, such as parks, beaches, and 

lawns. 

Management Methods

The most effective way to resolve wildlife damage is to 

integrate the use of several management methods either 

simultaneously or sequentially. The philosophy behind 

integrated pest management (IPM) is to implement the 

best combination of effective management methods in a 

cost-effective manner while minimizing the potentially 

harmful effects on people, target and non-target species, 

and the environment. IPM may incorporate cultural 

practices (e.g., no feeding policies), habitat modification 

(e.g., exclusion), animal behavior modification (e.g., 

U.S. Department of Agriculture Page 3

Figure 3. Area completely denuded of submerged aquatic vegetation by 

mute swans feeding in the area along the Detroit River, Michigan. Area 

exposed as water level dropped.
water and land. This method is less effective with mute 

swans than with other waterfowl species, such as Canada 

geese (Branta canadensis), because mute swans do not 

feed on land and do not often loaf on land. 

Removing submerged aquatic vegetation (food source) and 

emergent vegetation (nesting materials) may also help. 

However, this impacts other wildlife and fish at the site, 

and may not be practical. 

Mute swans require open water during winter months, 

therefore, removing aerators and allowing ponds to freeze 

will force the swans to leave. Again, this may impact other 

wildlife and fish at the site and may not be practical.

Exclusion

Like shrubs and boulders, adding electric fencing to a site 

may prevent swans from moving between the water and 

land. As with modifications to the shoreline habitat, this 

method is less effective with mute swans than with other 

waterfowl species. The use of electric fencing is usually 

limited to developed, nonrecreational sites because of 

potential risks to people or pets and may be prohibited in 

some areas. This method is not recommended for natural 

areas, such as wildlife refuges, given it could negatively 

impact nontarget species.

Other physical barriers and fencing, such as lawn furniture, 

vehicles, boats, snow fencing, plastic hazard fencing, metal 

wire fencing and multiple strand fencing, have been used 

to limit waterfowl movement, but have limited 

effectiveness. Fencing materials are most effective if the 

area to be protected can be completely enclosed and 

prevents birds from landing inside. Barriers are most 

effective when deterring small numbers of breeding mute 

swans and their flightless young from entering small 

portions of wetlands or waterways. 

Mute swans may be excluded from small ponds using wire 

grids. Overhead wire grids are most effective and 

applicable to ponds less than 2 acres. Wire grids may be 

aesthetically unappealing to some people, and render a 

pond unusable for boating, swimming, fishing, and other 

recreational activities. Birds may also be deterred from 

using a pond by covering the pond’s surface with 5-inch 

diameter floating balls. 

Page 4 WDM Technical Series─Mute Swans

frightening devices), nonlethal or lethal removal of 

individual animals, local population reduction, or any 

combination of these. The course of action depends on the 

circumstances of the specific damage problem. Consider 

the biology and behavior of the damaging species and 

other factors when developing an IPM strategy. The 

recommended strategy may include any combination of 

preventive and corrective actions. 

Preventive damage management applies IPM strategies 

before damage occurs, based on historical problems and 

data. Most preventive management techniques are 

nonlethal methods, and are most commonly applied by the 

resource owner or manager. An example is installing and 

maintaining a fence and/or overhead wire grid system to 

reduce mute swan access to a retention pond.

Corrective damage management uses IPM strategies to 

stop or reduce current conflicts. Both nonlethal and lethal 

methods may be used for corrective damage management. 

Examples include using pyrotechnics or border collies to 

chase away birds, removing breeding pairs of mute swans, 

or oiling eggs. 

Habitat Modification

Habitat modification can include planting vegetation that is 

unpalatable to wildlife or altering the physical habitat. 

Fences, hedges, shrubs, boulders, etc. can be placed at 

shorelines to impede mute swan movements between 

Figure 4. Mute swan nest built of bulrushes surrounded by a large floating 

mat of ripped-up vegetation.
Nest Treatment

Egg oiling or puncturing can help reduce local mute swan 

populations. These methods involve locating the birds’ 

nests and treating the eggs by either coating the eggs with 

corn oil or puncturing the eggshells, and then returning the 

treated eggs to the nest. The adult birds will continue to 

incubate the eggs and delay any attempts to re-nest. 

Generally, nests are visited more than once per breeding 

season to treat eggs. To ensure all eggs are treated, the 

nests must be treated during the incubation stage. If 

multiple swan nests are present at a particular site, they 

may have started nesting at different times and, therefore, 

some may be incubating while others are still laying or 

hatching. Treating swan nests is time and labor intensive 

and may not be the best method for quickly reducing mute 

swan populations. This method is primarily used with 

small, local swan populations in situations where the goal 

is to maintain the population at its current level.

Nest destruction is also used to reduce mute swan 

reproduction and discourage the use of a specific site. It 

involves locating the nests, destroying the eggs, and 

removing nest material from the site or dismantling nests 

and scattering the materials around the nest location. 

Birds may abandon the nest location and, depending on 

when the nest was destroyed during the breeding season, 

may attempt to re-nest at another site. This method is 

generally more useful for relocating problem birds than to 

reduce the population because of the tendency for birds to 

relocate and re-nest. Nest treatment may not be allowed or 

may require a special permit in some areas, so consult 

state wildlife agency regulations. 

Fertility Control

None are available.

Frightening Devices

Hazing involves the use of visual, auditory and/or biological 

frightening stimuli to discourage birds from using an area. 

Birds hazed from one area where they are causing damage 

may simply move to another area and cause similar 

damage. Birds becoming accustomed to and eventually 

failing to respond to frightening devices (known as 

habituation) reduces the effectiveness of frightening 

devices. In general, hazing is not used to protect natural 

resources because it may negatively impact nontarget 

species.

Visual

Commonly used visual deterrents for birds include 

reflective tape, flags or similar objects. In Europe, high 

visibility tape has been effective at reducing mute swan 

damage to crops. However, the tool is impractical in many 

locations due to its cost and unattractive appearance on 

properties where it is used. Other studies have shown 

reflective tape to be ineffective and may be only a shortterm deterrent for mute swans.

Effigies depicting alligators, people and floating dead birds 

have deterred some bird use for short periods of time in 

small areas. Although scarecrows have been used to 

reduce migrant Canada goose use of agricultural fields in 

rural areas, they likely would not be as effective with mute 

swans since the birds have little fear of people. Like most 

frightening devices, the efficacy of scarecrows may be 

improved/extended through the occasional use of lethal 

methods (e.g., shooting,) to reinforce the threat associated 

with the frightening devices. Often, reinforcement with 

lethal methods is not an option in urban and suburban 

areas.

The effectiveness of lasers as a nonlethal bird deterrent 

has been tested on a number of species. In some studies, 

waterfowl showed avoidance reactions to lasers under low 

light conditions. In field tests, lasers were effective at 

dispersing large waterfowl flocks from a lake, with nearly 

no habituation to the technique. Wide-scale public use of 

lasers for dispersing swans is not recommended until 

additional research on the lasers’ effectiveness and 

impacts to mute swans is completed. 

Audio

Pyrotechnics (i.e., screamer shells, bird bombs, and 12-

gauge cracker shells) are commonly used to disperse 

birds. Studies show the effectiveness of pyrotechnics can 

U.S. Department of Agriculture Page 5
Page 6 WDM Technical Series─Mute Swans

vary among different flocks of waterfowl. Some flocks in 

urban areas required continuous harassment throughout 

the day with frequent discharges of pyrotechnics. The 

waterfowl usually return to the area within hours. In 

Virginia, some flocks of Canada geese showed a quick 

response to pyrotechnics during winter months, suggesting 

migrant geese made up some or all of the flock. Mute 

swans are not a hunted species in the U.S., so 

pyrotechnics may be less effective with them versus 

migrant Canada geese. The effectiveness of pyrotechnics 

is partially dependent on the availability of alternative 

loafing and feeding areas. Because of safety and legal 

issues regarding their use, pyrotechnics may be 

inappropriate and prohibited in some areas. 

Propane cannons are generally inappropriate for use in 

urban and suburban areas due to their repeated loud 

explosions which many people consider a nuisance and 

possible health threat (hearing damage). Although a 

propane cannon can be an effective dispersal tool for 

migrant waterfowl in agricultural settings, resident 

waterfowl in urban areas are more tolerant of noise and 

habituate to propane cannons relatively quickly. Since 

mute swans are not hunted in the U.S., propane cannons 

may not be effective.

Biological

Dogs are often used to harass waterfowl and keep them off 

of lawns and beaches. Around water, this technique 

appears to be most effective when the water body is 

smaller than two acres. Using dogs or other harassment 

techniques requires an ongoing financial and/or personnel 

commitment in order to be effective. When harassment 

with dogs ceases, the number of birds often returns to pretreatment levels. The use of dogs is not recommended 

when birds are molting or fledging, and are unable to fly. 

Repellents

Methyl anthranilate (MA), an artificial grape flavoring food 

additive, is a registered repellent for use with waterfowl. It 

is marketed under a variety of trade names. 

The effectiveness of MA appears to be mixed. One study 

reported that MA repelled Canada geese from grazing turf 

for four days. However, another study found it ineffective 

as a grazing repellent when applied at 20.2 pounds (label 

rate) and 60.5 pounds (triple the label rate) per acre. 

MA is water-soluble, therefore moderate to heavy rain, 

daily watering or mowing render MA ineffective. More 

recent formulation strategies have been developed to 

address some of the problems associated with water 

solubility. 

Instead of spraying it directly on a surface, MA may be 

applied more cost-effectively using a fog-producing 

machine. The fog drifts over the treated area and is 

irritating to exposed birds. It is not irritating to people. In 

contrast to the turf application, the manufacturer 

estimates that a one-gallon container of 40% MA 

concentrate for use in fogging applications is sufficient to 

treat up to 16 acres, depending on airflow. Several 

treatments spaced 1 to 4 days apart may be required to 

disperse nuisance birds. As with the turf application, it is 

likely that additional applications would be required to 

address conflicts with migrating or non-resident birds. 

MA can be applied to temporary pools of water (e.g., water 

on airport runways or taxiways), but may not be directly 

applied to permanent water bodies, such as lakes, ponds, 

streams and rivers. 

Shooting

Shooting mute swans can be highly effective for removing 

or reducing local populations and for reinforcing 

harassment activities. The shooter must be trained in the 

safe and effective use of firearms, and be able to 

distinguish between mute swans and other swan species. 

Shooting may not be allowed or may require a special 

permit in some areas, so consult state wildlife agency 

regulations. In addition, check local ordinances which may 

further restrict the use of firearms or require special 

permits and/or notification.

Shooting mute swans may not be a viable option, even if it 

is legal, simply due to public relations. Mute swans are a 
highly charismatic species. Often, people become 

accustomed to seeing the swans and enjoy viewing and 

even feeding them. Individuals that become emotionally 

attached to swans may consider any type of lethal 

management as inhumane. 

As with any long-lived species that has multiple young 

every year, lethal removal of adult breeding mute swans is 

the most effective method of reducing populations. In 

addition, shooting a few individuals from a larger flock can 

reinforce the birds’ fear of other harassment techniques. 

A 12-gauge shotgun can be highly effective for shooting 

mute swans up to 50 to 75 yards, especially if several 

swans are to be removed in a quick manner. A mid-sized 

duck shot (Nos. 2 to 3 shot size) is recommend for head 

shots at stationary swans within 50 yards. A larger shot 

(BBB or T shot size) is recommended if swans are in flight 

or farther than 50 yards. Rifles are more effective for 

longer-range shots, and may have advantages if equipped 

with sound-suppressors. For removing single mute swans 

(e.g. aggressive male that has attacked people), a .22-

caliber rifle can be used at close range (less than 30 

yards). Mid-size rifle calibers (e.g. .223 to .243) are 

recommended for shooting swans effectively up to 300 

yards. 

All ammunition used for removing mute swans should be 

non-toxic (no lead). A wide variety of steel or “heavier-thanlead” alloys are available for shotguns, and are required by 

law for use in areas with water. Although not necessarily 

required by law, it is highly recommended that non-toxic 

rifle bullets be used. To reduce the risk of ricochets on 

water, a highly frangible bullet is also recommended. 

Availability of highly-frangible, non-toxic rifle ammunition is 

currently limited to a few sources. The Varmint Grenade® 

by Barnes Bullets and the Controlled Chaos by Lehigh 

Defense, LLC are two options.

Toxicants

No toxicants are currently registered for use with mute 

swans.

Trapping

Birds may be captured with panel nets, rocket nets, drive 

traps, net guns, hoop nets or by hand. Mute swans typically 

molt from late July through August or early September. 

Molting mute swans do not typically loaf on land as Canada 

geese do, so capturing mute swans using panel nets or 

drive traps is less effective than with Canada geese. 

Rocket netting involves setting bait in an area that would 

be completely contained within the dimensions of a 

manually propelled net. The launching of the rocket net 

occurs too quickly for the birds to escape. Net guns are 

typically shoulder-mounted or hand-held. Rocket nets and 

net guns may be used anytime during the year. Again, 

consult the state wildlife agency to determine if mute 

swans can be captured and, if so, whether they can be 

relocated and released. If relocation is not allowed, 

euthanize captured mute swans by one of the methods 

approved by the American Veterinary Medical Association. 

Handling

Mute swans are large, strong birds and have little fear of 

people. Their strong wings are capable of inflicting bruises, 

sprains and other injuries to a handler. It is important to 

obtain proper training before handling any live swan to 

prevent injury to the handler and the bird. 

Relocation

Check local and state regulations regarding the relocation 

of mute swans. Even if it is legal to relocate mute swans, it 

is not recommended because mute swans are a nonnative, invasive species. Relocating mute swans may result 

in damage to the area and further promote the spread of 

the species. If a mute swan must be relocated, it is 

recommended that it be surgically sterilized, rendered 

incapable of flight, and released on privately-owned land 

with the permission of the landowner. 

Euthanasia

Conduct euthanasia of mute swans in a safe, humane and 

effective manner. Refer to the American Veterinary Medical 

Association’s guidelines for recommended methods of 

euthanasia. 

U.S. Department of Agriculture Page 7
Page 8 WDM Technical Series─Mute Swans

Disposal

Euthanized mute swans must be buried, disposed of in 

landfills, or incinerated according to state or local 

regulations. 

Economics

Little has been published on the economic costs 

associated with mute swan damage. The primary damage 

is the consumption of submerged aquatic vegetation, and 

destruction of habitat that is a valuable resource to other 

wildlife and fish. Mute swans also directly compete with 

other waterfowl for food and breeding habitat, and may act 

aggressively towards them, sometimes even killing them. 

These impacts are not easy to quantify. Furthermore, 

threats to human safety from aggressive swans, and 

disease risks due to fecal contamination, are subjective. 

Costs are incurred when sites must be cleaned or closed 

because of the presence of mute swans and/or the 

accumulation of mute swan feces. 

Limited data exists on mute swan collisions with aircraft. In 

the U.S. from 1994 to 2011, there were eight reported 

mute swan strikes in the Federal Aviation Administration 

Wildlife Strike Database. There were no data recorded on 

the specific costs for damage incurred for any of these 

strikes. However, one strike report noted a flap skin was 

punctured and the plane was taken out of service for 

repair. Another strike report noted that a flock of five mute 

swans crossed the flight path immediately after takeoff 

and the pilot used evasive maneuvers to avoid colliding 

with the birds. Bird remains were subsequently recovered 

from the runway.

Species Overview

Identification

The mute swan is a member of the order Anseriformes and 

the family Anatidae which include ducks, geese and swans. 

They are one of six species in the genus Cygnus (swans). 

Two of these species, trumpeter swan (C. buccinators) and 

tundra swan (C. columbianus) are native to North America.

Physical Description

Adult mute swans are easy to recognize due to their large 

size, all white feathers and bright orange bills. Males 

typically weigh 20 to 25 pounds, and females are slightly 

smaller at 16 to 20 pounds. Wing spans typically are 7 to 8 

feet for adult mute swans. They are distinguished from 

other white swans by their body size and bill color. Mute 

swans are larger than tundra swans which are typically 

around 13 to 15 pounds. However, body size cannot be 

used to distinguish mute swans from trumpeter swans. The 

best characteristic to use is bill color, as both tundra and 

trumpeter swans have black bills. Mute swans have a 

prominent black knob at the base of an orange bill 

(Figure 5).

Juveniles are more difficult to distinguish among the swan 

species. Body sizes vary depending on age and may 

overlap during the fledging stage. Juvenile swans of the 

three species vary in feather color as well, ranging from all 

gray to all white, with varying shades in between. Bill color 

can be similar among species, especially during the early 

stages of fledging when all three have gray-colored bills. As 

mute swans grow, bills begin to show shades of pink and 

eventually orange. The bills of tundra and trumpeter swans 

also may show shades of pink, but will eventually turn 

predominately black. The trained observer can use the 

shape of the bill to distinguish among the species of 

swans. The tundra and trumpeter swans have a more 

wedge-shaped bill compared to the mute swan’s sloping 

bill and small knob.
Range

Mute swans are native to Eurasia. They were introduced 

into the U.S. in the late 19th and early 20th centuries for 

ornamental ponds and lakes, zoos and aviculture 

collections. Original populations were located in 

northeastern states and feral breeding was believed to 

have first started among escaped birds in the lower 

Hudson Valley in 1910 and on Long Island in 1912. 

Mute swans have since expanded their range to many 

eastern states, several Midwestern states and portions of 

the western U.S. and Canada (Figure 6). Established feral 

populations exist along the northern Atlantic coast, in the 

Great Lakes region, and the Pacific Northwest. Small 

localized populations of mute swans may be found in other 

locations throughout the U.S. due to intentional releases 

for aesthetic purposes. 

Voice and Sounds

Although the name suggests mute swans make no sounds, 

this is not the case. Mute swan vocalizations are much 

quieter than other swans and do not carry far. They usually 

are limited to snorting or hissing when aggravated. Mute 

swans also emit a quiet trill or bugle to communicate with 

their mates or young. During flight, their large wings make 

a distinctive whistling who who sound that is relatively loud 

compared to their voice.

Tracks and Signs

Due to their webbed feet, the tracks of mute swans are 

similar to other waterfowl, but much larger than those of 

ducks and geese. Track size is indistinguishable from 

trumpeter swans. Other mute swan signs include large 

fecal droppings, areas where aquatic vegetation has been 

removed and gathered into mounds for nests, and the 

presence of long, white flight feathers during the molting 

period. 

Reproduction

Mute swans typically are monogamous, but have been 

known to separate and find new mates, particularly when 

breeding fails. A mute swan typically finds a new mate 

when its partner dies. The size of the breeding territory 

varies depending on the quality of the habitat, density of 

other breeding mute swan pairs, and the aggressiveness of 

that particular pair. Non-breeding mute swans do not 

U.S. Department of Agriculture Page 9

Figure 5. Bill colors and shapes of North American swans.

Figure 6. Range of mute swans.
Page 10 WDM Technical Series─Mute Swans

establish territories, but rather congregate with each other 

throughout the year.

Mute swan nests are similar to Canada goose nests in 

construction and placement, but are about twice the size, 

averaging 5 to 6 feet in diameter and 1.5 to 2 feet high. 

Mute swans typically use emergent wetland vegetation to 

construct their nests. If emergent vegetation is lacking, 

they use other materials, such as sticks and floating 

debris. Nests usually are situated away from shorelines to 

minimize threats from predators. If emergent vegetation is 

lacking, mute swans may nest on shorelines or on islands.

Mute swans usually lay one egg every 2 days until the 

clutch is complete. The average clutch size varies in 

different regions, but an overall average is between 5 to 6 

eggs. Most males are highly territorial during egg-laying, 

and some will help with incubation by sitting on the nest to 

allow the female to feed. Nesting periods vary among 

regions, but typically begin in March. Hatching occurs in 

May or June. Cygnets grow very quickly and are able to 

swim almost immediately after hatching once their down 

feathers dry (Figure 7). Adults protect cygnets from 

predators and other waterfowl (including other mute 

swans), and uproot vegetation for the cygnets to eat. By 

August, cygnets usually are similar in size to adults and 

have lost all their downy plumage. 

Mortality

Cygnet mortality rates are relatively unknown due to 

variations in site characteristics, such as availability of 

food, density of other mute swans, presence of particularly 

aggressive mute swans and predators. In one 20-year, 

mark-recapture study, cygnet mortality was estimated at 

60 to 70 percent. Once the mute swans fledged, the 

mortality rate decreased to about 30 percent for subadults and 10 percent for breeding adults.

Population Status

Because mute swans are an introduced species and 

people can purchase and place them (with special permits) 

on their property, mute swans can be found in many areas 

of the United States. Feral populations of mute swans 

occur in three areas of the country: 1) the northeast coast, 

2) the Great Lakes region, and 3) the northwest coast. 

Within these areas, mute swans vary in densities from 

single swans or pairs to over a thousand birds. Several 

states have developed management plans to reduce the 

number of feral mute swans breeding in natural habitats to 

prevent competition with native waterfowl and colonial 

waterbirds.

Habitat 

Mute swans are found in a variety of habitats with water. 

Mute swans typically are not afraid of people. They can be 

found in highly-developed areas, such as densely 

populated lakes, city parks, subdivisions, airport retention 

ponds and marinas. As feral populations have grown, 

however, they have expanded into more natural habitats 

including lakes, emergent wetlands, rivers and coastal 

areas of large waters (e.g., the Great Lakes and 

Chesapeake Bay). 

Behavior

Mute swans are primarily diurnal and feed almost 

exclusively on submerged aquatic vegetation. In times of 

stress when food is limited, mute swans have been 

documented feeding on small fish. Figure 7. Mute swans with cygnets.
Figure 9. Mute swan feeding on aquatic vegetation and insects.

Mute swans are non-migratory, but they do make local 

flights during different seasons (Figure 8). During winter in 

the northern climates, mute swans fly to areas with open 

water and often gather in large concentrations. When the 

ice starts to thaw, the swans return to their breeding sites. 

Breeding adults remain at these sites until the fall when 

their cygnets are old enough to fly and fend for themselves. 

Non-breeding sub-adults disperse in the spring to sites with 

suitable habitat. This may be their birth site or a new area, 

depending upon the aggressiveness of adult birds in the 

area. Non-breeding sub-adults undergo a molt in mid to 

late summer (July to August) and typically migrate to larger 

bodies of water. Breeding adults remain with their cygnets 

and molt at breeding sites. 

Food Habits

Mute swans eat throughout the day, from sunrise to shortly 

after sunset. The main food source of mute swans is 

submerged aquatic vegetation (Figure 9). They also 

consume small fish, insects and other small animals 

incidentally along with plants and when plants are sparse. 

They prefer shallow waters where they can reach the 

bottom. 

Because of their long necks, mute swans can exploit areas 

in far deeper water than geese and dabbling ducks. Mute 

swans use their feet while feeding to expose plant 

rhizomes and to help dislodge food for cygnets. In one 

study, mute swans consumed less than 50 percent of what 

they removed. 

During winter in northern climates, mute swans congregate 

in areas of open water and may feed exclusively on small 

fish or algae if submerged aquatic vegetation is lacking. In 

the U.S., mute swans rarely feed on land. When they do, 

they may feed on crops or grasslands near shores. 

In areas with human development, mute swans readily 

habituate to artificial feeding. Begging behavior becomes 

more prevalent when aquatic vegetation is limited. Artificial 

feeding has been responsible for maintaining populations 

in British Columbia and Traverse City, Michigan.

Legal Status 

Some have questioned the status of mute swans as an 

introduced species, but multiple reviews by scientists and 

the U.S. Fish and Wildlife Service clearly support the 

conclusion that mute swans are not native to North 

America. The Migratory Bird Treaty Act, therefore, does not 

protect mute swans, and management authority falls 

under jurisdiction of the states and Tribes. 

Before initiating any damage management actions, consult 

the state wildlife agency regarding the status of mute 

swans in your area. Management options may be limited 

and special permits may be required. 

U.S. Department of Agriculture Page 11

Figure 8. Mute swan in flight.
Page 12

Acknowledgements

Figure 1. Photo by USDA

Figure 2. Photo by Wikimedia Commons

Figure 3. Photo by Friends of the Detroit River

Figure 4. Photo by Michigan Department of Natural Resources

Figure 5. Graphic by Trumpeter Swan Society 

Figure 6. Map by The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology

Figure 7. Photo by Wikimedia Commons

Figure 8. Photo by Wikimedia Commons

Figure 9. Photo by Wikimedia Commons

Special thanks to Dusty Arsnoe, Jason Suckow, Caleb Wellman for their critical review.

Key Words

Aggressive birds, Cygnet, Cygnus olor, Invasive species, 

Mute swan, Waterfowl

Disclaimer

Wildlife can threaten the health and safety of you and 

others in the area. Use of damage prevention and control 

methods also may pose risks to humans, pets, livestock, 

other non-target animals, and the environment. Be aware 

of the risks and take steps to reduce or eliminate those 

risks. 

Some methods mentioned in this document may not be 

legal, permitted, or appropriate in your area. Read and 

follow all pesticide label recommendations and local 

requirements. Check with personnel from your state 

wildlife agency and local officials to determine if methods 

are acceptable and allowed. 

Mention of any products, trademarks, or brand names 

does not constitute endorsement, nor does omission 

constitute criticism. 

Citation

Marks, D.R. 2018. Mute Swans. Wildlife Damage 

Management Technical Series. USDA, APHIS, WS National 

Wildlife Research Center. Fort Collins, Colorado. 14p.

Glossary

Aviculture: The breeding and rearing of birds. 

Bird strike: The collision between a bird or flock of birds 

and an airplane. 

Cygnet: A young swan.

Diurnal: Active during the day. 

Effigy: An artificial likeness. 

WDM Technical Series─Mute Swans
 Page 13

Resources

Ciaranca, M., C.C. Allin, and G.S. Jones. 1997. Mute Swan (Cygnus olor). Pages 273-300 in A. Poole and F. Bill, editors. 

The Birds of North America, No. 273. The Academy of Natural Sciences, Philadelphia, Pennsylvania and The American 

Ornithologists’ Union, Washington, D.C.

Cornell Lab of Ornithology – All about birds: Mute swan. http://www.allaboutbirds.org/guide/mute_swan/id.

Ellis, M.M. and C.S. Elphick. 2007. Using a stochastic model to examine the ecological, economic and ethical 

consequences of population control in a charismatic invasive species: Mute swans in North America. Journal of Applied 

Ecology 44:312-322.

Frequently Asked Questions about Mute Swans. http://www.michigan.gov/dnr/0,4570,7-153-

10370_12145_59132_59333-263394--,00.html.

Maryland Department of Natural Resources. 2003. Mute swans in Maryland: A statewide management plan. Maryland 

Department of Natural Resources Wildlife and Heritage Service. 

http://dnr.maryland.gov/wildlife/Documents/MuteSwan_StatewideMgtPlan.pdf.

Michigan Department of Natural Resources. 2012. Mute Swan management and control program policy and procedures. 

https://www.michigan.gov/documents/dnr/2012_Mute_Swan_Policy_378701_7.pdf.

Mississippi Flyway Council. 2012. Mississippi Flyway Council Policy – Management of Mute Swans. Mississippi Flyway 

Technical Section. https://www.michigan.gov/documents/dnr/

Mississippi_Flyway_Council_Mute_Swan_policy_364885_7.pdf.

Mute swans in Maryland. http://dnr.maryland.gov/wildlife/Pages/plants_wildlife/Invasives/inv_MuteSwan.aspx.

Mute swans in Michigan. http://www.michigan.gov/muteswans. 

Pedersen, K., D.R. Marks, D.M. Arsnoe, S.N. Bevins, E. Wang, S.C. Weaver, R. M. Mickley, and T.J. DeLiberto. 2014. Short 

Report: Antibody prevalence of select arboviruses in Mute Swans (Cygnus olor) in the Great Lakes region and Atlantic 

coast of the United States. The American Journal of Tropical Medicine and Hygiene 91(6):1247-1249. doi: 10.4269/

ajtmh.14-0280.

United States Department of Agriculture Wildlife Services. 2012. Final Environmental Assessment: Mute Swan Damage 

Management in Michigan. http://www.aphis.usda.gov/regulations/pdfs/nepa/Mute%20Swan%20EA%20Final%209-27-

12.pdf.

U.S. Department of Agriculture
Appendix 

Page 14

 

 

Type of Control 

 

Available Management Options 

Exclusion  Install fencing or other barriers along shoreline, around ponds and yards to prevent access 

 Install overhead wire grids or netting on ponds

Fertility Control None available

Frightening Devices  Pyrotechnics and propane cannons

 Mylar® tape, flags, balloons and effigies

 Dogs or human presence in an area 

Habitat Modification  Modify shoreline habitat to impede movement onto land

 Remove vegetation used for nesting and feeding

 Allow ponds and lakes to freeze in winter

Nest Treatment Allowed with proper State permits; Egg oiling or puncturing of eggshells and nest destruction

Repellents Methyl anthranilate

Shooting Allowed with proper State permits or hunting licenses

Toxicants None available

Trapping Allowed with proper State permits; Live-trapping with rocket or cannon nets, swim-in funnel traps, net 

guns or by hand

Damage Management Methods for Mute Swans