The mute swan gets its name from the fact that it does not make the loud trumpeting sounds that other swans are known for. Unlike the whooper swan and trumpeter swan, the mute swan is silent for much of its life, leading to its descriptive name.
The Voice of the Mute Swan
While mute swans do make some sounds, they are generally much quieter than other swan species. The most common sound made by mute swans is a soft hoarse whistle used to communicate between mates or between parents and cygnets (baby swans). The voice of the mute swan has been described as grunting, snorting, or puffing, but not the loud, resonant honking or trumpet-like sounds of other swans.
Adult mute swans are mostly silent, but cygnets and juveniles use quiet chirping or whistling sounds to communicate with their parents. The female mute swan, called a pen, uses quiet grunts and snorts to talk to her mate or cygnets. Male mute swans, called cobs, make hissing noises when threatened or defending their territory.
While mute swans don’t make loud honking calls, they do have a repertoire of snorts, grunts, hisses, and whistles to communicate essential information within their flock. Their most common vocalizations are substantially quieter than the noisy trumpeting of other swan species, lending the mute swan its descriptive name.
Comparison with Other Swans
In contrast to the nearly silent mute swan, the trumpeter swan of North America is known for its loud, resonant, trumpet-like call that can be heard from miles away. Trumpeter swans use their trumpet call to communicate with flock members over long distances. Another swan famed for its voice is the whooper swan of Eurasia, whose far-carrying, melodious call has been described as sounding like a musical wind instrument.
The most similar species to the mute swan is the black swan of Australia. Like the mute swan, the black swan is relatively silent, uttering only occasional croaks, whistles and fanfare calls. However, while black swans may be quieter than other swans, they are not as silent as the mute swan and do make loud calls on occasion.
The mute swan’s silence is unique among swans, making it stand out from its noisy relatives in other parts of the world. This lack of loud honking calls is the origin of its name.
Reasons for the Mute Swan’s Silence
There are a few theories as to why mute swans lack the loud voice of their close relatives:
- They evolved in a different habitat – Unlike trumpeter swans which migrated in noisy flocks over long distances, mute swans lived a more sedentary lifestyle in Europe with less need for long-distance communication.
- Adaption to their habitat – Mute swans may have developed quieter habits to avoid detection in reed beds where they nested.
- Physiological differences – Some experts believe anatomical differences like a reduced syrinx (vocal organ) may limit mute swans’ ability to make loud calls.
- Genetic differences – There may be genetic factors that separate mute swans from other vocal swan species.
In the end, the evolutionary reasons for the mute swan’s nearly silent behavior are still not fully understood. Their lack of loud honking calls nevertheless gives them their distinctive common name.
Sounds Mute Swans Make
While mute swans are mostly silent birds, they do make some quiet vocalizations. Here are some of the sounds mute swans can produce:
Snorts and Grunts
Mute swans use soft snorts and grunts to communicate with flock members at close range. These short, quiet noises convey information like warnings or signaling location between mates and offspring.
Hissing
A hissing noise, similar to the hiss of a goose, is made by mute swans to signal danger or when defending territory or a nest. The hissing sound warns other animals that the swan feels threatened.
Whistling
Mute swan cygnets and juveniles use a whistling sound to keep in contact with parents. The whistling call allows them to indicate their location over short distances.
Occasional Croaks
While uncommon, mute swans may make occasional brief, hoarse croaking noises. These guttural croak sounds are most often heard from breeding males during the mating season.
Wing Sounds
The sound of mute swans’ wings when flying is often associated with their flight call. The slow, labored flapping of their wings as they take flight produces a muted throbbing sound.
While not totally silent, the various sounds mute swans produce are generally very quiet compared to other swan species. They lack the loud trumpeting or bugling calls that give other swans their musical voices.
When Do Mute Swans Vocalize?
While mute swans are quiet most of the time, there are some situations when they may vocalize more than usual:
- Breeding Season – Male mute swans may make hoarse croaking noises when claiming territory and attracting a mate in spring.
- Territorial Defense – Hissing is used to fend off rival swans encroaching on a mute swan’s territory.
- Nesting – Female mute swans use quiet grunts and snorts to communicate with their cygnets at the nest.
- Flying – The throbbing wing sound and occasional whistling may be heard when mute swans are in flight.
- Warning Signaling – Grunts or hisses are used to signal danger or a threat within the flock or family.
While not loud birds in general, mute swans do vocalize more when communicating essential information in key situations like breeding, nesting and defending territory.
Do Mute Swans Make any Loud Sounds?
Though mute swans are famously quiet compared to other swan species, they have very occasionally been reported to make loud calls. These unusual loud vocalizations include:
Snoring Call
Some reports note certain populations of mute swans emitting a surprisingly loud, snoring-like vocalization. These unusual snoring calls seem to be made only by certain flocks in isolated areas.
Alarm Call
When extremely alarmed or frightened, mute swans may sometimes make loud cracking or trumpeting sounds as a warning call to signal imminent danger within the flock.
Triumph Ceremonies
In the mating season, mute swan pairs may engage in loud and elaborate triumph ceremonies after driving off a rival swan. These noisy celebrations are characterized by calling, wing-flapping and splashing.
However, these loud calls are extremely uncommon and do not represent the typical silent behavior of mute swans. The vast majority of mute swans do not make loud sounds as part of their normal behavior.
Do Mute Swans Make Sounds When Flying?
Mute swans do make some noise during flight, but these sounds are quiet compared to the noisy wing beats of other waterfowl. The sounds mute swans produce while flying include:
- Quiet whistling or grunting vocalizations
- Some rustling sounds from their large wings flapping slowly
- Gentle throbbing or whooshing wing beat noises
The large wings of mute swans beating slowly produce minimal sound compared to ducks or geese. Combined with their muted vocalizations, mute swans are among the quietest of flying birds. However, their great size does mean their wing-flapping produces some gentle throbbing noises audible to nearby observers.
Geographic Variation in Sounds
The typical sounds made by mute swans may vary somewhat depending on their geographic location. Some differences include:
Northern Europe
Mute swans in England, Scandinavia and Russia exhibit classic mute swan behavior, being almost entirely silent. These northern European mute swans use only occasional soft grunts and whistles to communicate.
Southern Europe
In parts of southern Europe like Spain, Italy and Greece, mute swans may make rattling or harsh grunting noises more frequently than swans further north. But southern European mute swans remain very quiet compared to other swan species.
Asia
The isolated mute swan populations of Asia have some of the most divergent vocalizations. In Asia, mute swans may make unusual snoring-like honking sounds and more loud alarm calls compared to European flocks.
While there are some minor regional variations, the core characteristics of mute swan vocalizations remain soft grunts, hoarse whistles and hissing sounds across their global range.
Conclusion
In the end, mute swans are named for their lack of the loud trumpeting calls that define other swans. While not completely silent, mute swans rely on soft snorts, grunts and whistles to communicate rather than noisy honking. Their quiet nature starkly contrasts with the boisterous vocals of their close swan relatives. Even in flight, mute swans produce only muffled throbbing wing beats rather than the loud whistling of many waterfowl. The mute swan’s hushed characteristics reflect its evolutionary adaptation to its habitat and distinguish it from other, more loquacious swan species around the world.