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Mute Swan

Scientific name: Cygnus olor

New York State Mute Swan Management Plan

Picture of a mute swan swimming.
Mute swan swimming.

Mute Swans in New York: A Final Management Plan to Prevent Population Growth and Minimize Impacts of a Non-Native Invasive Species (PDF)

This plan provides guidance to New York State Department of Environmental Conservation (DEC) staff and the public concerning management of mute swans (Cygnus olor). Mute swans are a non-native, "invasive" species that many people enjoy seeing despite adverse impacts the birds can cause. The plan strives to balance these competing values by accepting the continued existence of some feral mute swans in the wild, while preventing any further population growth or range expansion. It also supports efforts by DEC and others to prevent or alleviate site-specific conflicts with mute swans that may be experienced by public or private property owners and outdoor enthusiasts. Based on extensive public input over the past three years, the plan gives priority to non-lethal management techniques, documents the scientific basis for population projections and environmental impacts, and emphasizes public outreach and education as a management strategy.

Related documents

2017 Biennial Mid-Summer New York Swan Survey (PDF)

Status and Ecology of Mute Swans in New York State (December 2013) (PDF)

DEC Responses to Public Comments on the Third Draft Management Plan for Mute Swans in New York State (January 2019) (PDF)

Mute swans are most numerous on Long Island and in the lower Hudson Valley, but they have expanded their range in recent years especially around Lake Ontario. Mute swans can cause a variety of problems, including aggressive behavior towards people, destruction of submerged aquatic vegetation, displacement of native wildlife species, degradation of water quality, and potential hazards to aviation. This plan supports actions by DEC to minimize the impacts of swans, while allowing them to remain in urban parks and other controlled settings. DEC recently adopted regulations listing mute swan as a "prohibited" Invasive Species, which prohibits the sale, importation, transport, or introduction of this species in New York.

History in New York

Mute swans are a non-native, invasive species first brought to this country from Europe in the late 1800s for their aesthetic value. Initially introduced in New York's lower Hudson Valley and Long Island, mute swans were kept by breeders as domestics on the ponds of private estates. The release of domestic swans into the wild on Long Island and the lower Hudson Valley has led to well established populations in those areas. The largest known releases occurred from 1910-1912 and consisted of about 500 birds.

By 1993, New York's mute swan population had increased to about 2,000. The population peaked at more than 2,800 birds in 2002 and is currently estimated at about 2,200 birds statewide. The largest numbers of swans still occur on Long Island and in the lower Hudson Valley, but a rapidly increasing population has taken hold in the Lake Ontario region (see the map of mute swan breeding locations in New York).

Map Showing Mute Swan Breeding Locations
Mute Swan Breeding Locations:
from NYS Breeding Bird Atlas Project.

Life History

Mute swans are the largest birds in New York, with an average adult weight of 20-25 pounds and a wing span of nearly 7 feet. Both sexes have a black face patch with a fleshy knob on the forehead that overlays an orange bill. These facial characteristics distinguish mute swans from other swan species in New York State. Males ("cobs") tend to have slightly larger knobs and body sizes than females ("pens"). Despite these differences, it is very difficult to tell the sexes apart. Mute swans, as indicated by their name, are not very vocal. They will, however, grunt, snort, or hiss to communicate, especially if threatened.

The diet of mute swans consists of submerged aquatic vegetation (SAV) found in water as deep as 4 feet. They eat a variety of plant species and consume about 4-8 pounds of vegetation daily, sometimes uprooting plants completely. Often, adult swans will uproot more plants than they actually consume. Submerged aquatic vegetation plays an important role in aquatic ecosystems by providing both food and cover to a variety of vertebrate and invertebrate species. In turn, many species (e.g., fish) rely on animals that live in SAV beds for food. Thus, loss of SAV caused by large flocks of feeding swans could have a detrimental impact on aquatic ecosystems.

Mute swans become sexually mature when they are two years old, but often will not begin breeding until they are three, four, or even five years old. Some individuals may pair and sometimes even build a nest when they are 1 year old, but will not breed.

Picture of a mute swan nest.
Mute swan nest.

The nesting period for mute swans begins in late March to April. Nests are large (4-5 feet across) with shallow depressions in the center. Nest sites will vary based on available habitat, but are typically in secluded areas on shore or in shallow water. In marshes, nests are often floating, constructed of cattail stems. Other nest materials include twigs, leaves, and stems of wetland plants, such as cattail and phragmites. Occasionally, nests will contain litter, such as paper, plastic wrappers, and fishing line.

Mute swans lay an average of 6 eggs but can produce as many as 11 in one clutch. The off-white to pale green eggs are laid at a rate of one per day, and hatch 35 days after the last egg is laid. The average hatch date for swans in New York is around June 1. Re-nesting may occur if the initial nest fails. Mute swan offspring ("cygnets") are either gray or white upon hatching. Their color at hatch is a genetic trait and not related to sex. Gray cygnets gradually turn a brownish color by their first winter, before gaining their white adult plumage. White cygnets remain white. Mute swan families typically stay close to their nesting area and separate from other broods and non-breeding swans for the first couple of months after hatching. Cygnets can fly at about 4-5 months of age and are considered "juveniles" at that time. On average, only 3 cygnets per breeding pair survive to juvenile age. Causes of death include starvation, collisions with structures and disease, including lead poisoning.

During the nesting and brood rearing-periods mute swans are very territorial. Both males and females are aggressive toward people and other waterfowl within their nesting area. Sometimes their behavior is so aggressive that they will drive other waterfowl out of areas where the swans are nesting. Reports of swan attacks on people, especially small children and users of personal watercraft, are common. Because of this, waters occupied by breeding swans are often unusable to people during the nesting and brood-rearing periods. Aggression among swans also occurs, especially when an adult male with a nest or brood encounters another male. In these instances both males raise their wings and fluff their feathers, known as "busking" (also part of the mating ritual), and begin twirling in place; a ritual that appears more like a dance than a fight.

Status and Ecology of Mute Swans in New York

Picture of three banded mute swans.

Concerns about the impact of mute swans on people, wildlife, and ecosystems prompted the New York State Department of Environmental Conservation (NYSDEC) to conduct field research on this species. From 2004-2007, researchers collected nesting and productivity data, documented survival and movement of neck-banded swans, compiled available population survey data, and investigated impacts of mute swans on aquatic vegetation, other wildlife and water quality. Results of this research, and other information about Mute Swans in New York, are summarized in a new report, Status and Ecology of Mute Swans in New York State (PDF, 446 KB).

Reporting Collared Mute Swans

Several of the swans tagged for our research are still being seen in New York. If you see one of these birds, please provide the following information to report a collared mute swan: your name, address, phone number, e-mail; date and time of sighting; location of the sighting (including county, town, name of water body, and nearest road intersection); collar identification code; and an estimate of the total number of mute swans observed in that location. Although our study is over, these sightings provide additional information about survival and movements of Mute Swans in New York.

Reporting Problems Related to Mute Swans

If you have concerns regarding mute swans impacting vegetation, wildlife, or human activities on your property, please contact the DEC wildlife office in your region. They can provide information or assistance to alleviate the problem. Remember, mute swans are protected by the New York State Environmental Conservation Law. Therefore, swans, as well as their nests and eggs, may not be handled or harmed without authorization from DEC.

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