Mute swan swimming
Scientific name: Cygnus olor
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. Currently, the population is believed to have increased further to about 3,000. 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).
Mute Swan Breeding Locations - NYS Breeding Bird Atlas Project
Mute swan nest
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.
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 disease, hypothermia, and predators. The most common predator of mute swan cygnets in New York is the snapping turtle.
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.
Current and Future Research
Concerns about the impact of mute swans on people, wildlife, and ecosystems have prompted the New York State Department of Environmental Conservation (NYSDEC) to initiate research on this species. In May 2004, researchers began collecting nesting and productivity data across New York State. These data provide information on nesting distribution, clutch sizes (eggs per nest), hatching rates, cygnet survival, and proportions of breeding birds within the populations.
Ground, boat, and aerial surveys are also being done across the state to monitor current population numbers, seasonal distribution and movement patterns, and habitat use. These data, along with productivity estimates, help to determine and predict population trends.
As part of this research, some swans have been tagged with identification markers, including aluminum leg bands, plastic neck collars, and even satellite-tracked radio-transmitters. Past research on swans and other waterfowl indicate that these methods of marking swans have little to no impact on the well-being of marked individuals.
Future research plans include:
- continuing studies of productivity, survival, and movements.
- determining the impact of mute swan feeding on submerged aquatic vegetation.
- documenting mute swan aggression toward people and other waterfowl.
- determining the extent to which feeding by people contributes to mute swan population growth and survival.
Reporting Collared Mute Swans
Please provide the following information when reporting a collared mute swan. Include 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. Your help in reporting mute swan sightings is an important part of the data collection process and is greatly appreciated.
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.
More about Mute Swan :
- Mute Swan Surveys - DEC conducts a Mid-summer Mute Swan Survey to assess the population status of this non-native species and to help evaluate the need for and success of management efforts.