---
title: "What the sources say about the Mute Swan | AnimalTracks.wiki"
description: "44 claims from the Mute Swan profile, each beside the words of the source that backs it."
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---

# What the sources say about the Mute Swan (*Cygnus olor*)

> 44 claims from the Mute Swan profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Mute Swan](https://animaltracks.wiki/animals/mute-swan/)

## Cygnus olor. The IUCN Red List of Threatened Species 2025: e.T22679839A281844289.

https://doi.org/10.2305/iucn.uk.2025-2.rlts.t22679839a281844289.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | Least Concern (note: GBIF copy of the Red List, taxon id checked against the DOI) |

## Wood et al. (2024). Mute Swan (Cygnus olor). Birds of the World.

https://doi.org/10.2173/bow.mutswa.02

| The page says | The source says |
| :--- | :--- |
| Birds of the World says the pair bonds often last for life | form strong pair bonds that often last for life |
| Often, though not always. Birds of the World says males and females form strong pair bonds that often last for life. | Males (properly called “cobs“) and females (known as “pens“) form strong pair bonds that often last for life. |
| Males and females form strong pair bonds that often last for life, and a pair bows and entwines necks each spring. | form strong pair bonds that often last for life (note: vibe.reason; same source as the body claim) |

## BirdFacts: Mute Swan. British Trust for Ornithology.

https://www.bto.org/understanding-birds/birdfacts/mute-swan

| The page says | The source says |
| :--- | :--- |
| From weighings of live birds, adult males average 10.75 kg and females 8.54 kg | Female 8.54±1.23 kg (6.3-10.5 kg, N=233) Male 10.75±1.56 kg (8.2-13.4 kg, N=314) (note: Averages from the Body weight table, adults by sex) |
| A bird that reaches breeding age typically lives 10 years, and breeding usually starts at four | Typical life expectancy of bird reaching breeding age 10 years with breeding typically at 4 years |
| The oldest bird in the British Trust for Ornithology's ringing records was 29 years old, a record set in 2009 | Maximum age from a ringed bird 29 years, 1 month, 11 days (set in 2009) |
| The grey cygnets turn grey-brown, then white, during their first year | the grey cygnets transform through grey-brown into white adults during their first year |
| Males are the heavier sex. Across 314 live adult males weighed for the British Trust for Ornithology, the average was 10.75 kg; across 233 adult females, 8.54 kg. | Female 8.54±1.23 kg (6.3-10.5 kg, N=233) Male 10.75±1.56 kg (8.2-13.4 kg, N=314) (note: Body weight table, adults by sex; weights are from live birds) |
| Ten years is typical for a swan that survives to breeding age, by the British Trust for Ornithology's ringing data. | Typical life expectancy of bird reaching breeding age 10 years with breeding typically at 4 years |
| The longest-lived bird in those records reached 29 years, 1 month and 11 days, a record set in 2009. | Maximum age from a ringed bird 29 years, 1 month, 11 days (set in 2009) |
| weightKg: 10.75 | Male 10.75±1.56 kg (8.2-13.4 kg, N=314) (note: task #1114: BTO's live-bird average for adult males; Medium, where the name guess gave Light. Not in a curated matchup) |

## Mute Swan. RSPB.

https://www.rspb.org.uk/birds-and-wildlife/mute-swan

| The page says | The source says |
| :--- | :--- |
| Lakes, rivers, canals and sheltered bays across Europe and Asia, introduced in North America | including lakes, rivers, canals and urban park ponds |
| Mainly aquatic plants, plus grass grazed from nearby fields | They feed mainly on aquatic plants, but also graze on grass in nearby fields and meadows. |
| Despite the name, mute swans are not silent. They often grunt softly while feeding and will hiss loudly if disturbed, especially when protecting their young | Despite their name, Mute Swans aren’t actually silent. They often grunt softly while feeding and will hiss loudly if disturbed – especially when protecting their young. |
| In flight, their wings make a whooshing sound | While flying, their wings make a dramatic whooshing sound |
| Newly hatched cygnets often hitch a ride on their parents' backs for warmth, protection and to save energy. | Newly hatched cygnets often hitch a ride on their parents’ backs for warmth, protection and to save energy. |
| In spring, pairs bow to each other with wings held aloft, then entwine their necks, often forming a heart shape | Each spring, pairs perform a beautifully synchronised courtship display out on the water, bowing to each other with wings held aloft, before entwining their necks, often forming a heart shape. |
| The female lays four to seven eggs and incubates them while her partner stands guard | The female lays a clutch of four to seven eggs, which she incubates while her partner stands guard. |
| Mute swans feed mainly on aquatic plants, and also graze on grass in nearby fields | They feed mainly on aquatic plants, but also graze on grass in nearby fields and meadows. |
| No. A feeding swan often makes quiet grunts, and a disturbed one hisses loudly, most of all near its cygnets. The wings are noisy too: you might hear a swan flying over before you see it. | They often grunt softly while feeding and will hiss loudly if disturbed – especially when protecting their young. While flying, their wings make a dramatic whooshing sound, so you might hear them coming before you see them! |
| Males and females form strong pair bonds that often last for life, and a pair bows and entwines necks each spring. | Each spring, pairs perform a beautifully synchronised courtship display out on the water, bowing to each other with wings held aloft, before entwining their necks, often forming a heart shape. (note: vibe.reason, second part) |

## Mute Swan. New York State Department of Environmental Conservation.

http://www.dec.ny.gov/animals/7076.html

| The page says | The source says |
| :--- | :--- |
| Not actually mute: it hisses, snorts and twirls with its wings raised. | mute swans, as indicated by their name, are not very vocal. However, they will grunt, snort, or hiss to communicate |
| Not actually mute: it hisses, snorts and twirls with its wings raised. | both males raise their wings and fluff their feathers, known as "busking" (also part of the mating ritual), and begin twirling in place |
| Raises its wings and twirls in a busking display, part of both rival standoffs and the mating ritual | both males raise their wings and fluff their feathers, known as "busking" (also part of the mating ritual), and begin twirling in place |
| When an adult male with a nest or brood meets another male, both raise their wings and fluff their feathers | when an adult male with a nest or brood encounters another male. In these instances both males raise their wings and fluff their feathers |
| This is called busking, and the two males then twirl in place | known as "busking" (also part of the mating ritual), and begin twirling in place |
| New York's wildlife agency says the ritual appears more like a dance than a fight | a ritual that appears more like a dance than a fight |
| Busking is also part of the mating ritual | known as "busking" (also part of the mating ritual) |
| Breeding mute swans are very territorial, and both sexes are aggressive toward people and other waterfowl within their nesting area | 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. |
| New York's wildlife agency says they eat about 4 to 8 pounds (1.8 to 3.6 kg) of vegetation a day | consume about 4-8 pounds of vegetation daily (note: task #1114: figure tied to its New York source, metric added) |
| New York's wildlife agency says they were first brought to the United States from Europe in the late 1800s, and it lists the mute swan as a prohibited invasive species | Mute swans are a non-native, invasive species first brought to this country from Europe in the late 1800s |
| it lists the mute swan as a prohibited invasive species | DEC recently adopted regulations listing mute swan as a "prohibited" invasive species |

## Cygnus olor (mute swan). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Cygnus_olor/

| The page says | The source says |
| :--- | :--- |
| Lakes, rivers, canals and sheltered bays across Europe and Asia, introduced in North America | They live in well-sheltered bays, open marshes, lakes, and ponds. |
| Lakes, rivers, canals and sheltered bays across Europe and Asia, introduced in North America | Mute swans breed in the British Isles, north central Europe and north central Asia. |
| Lakes, rivers, canals and sheltered bays across Europe and Asia, introduced in North America | They have been successfully introduced in North America |
| blows from their wings can be especially painful | Blows from their powerful wings can be especially painful. |
| there are records of swans knocking boaters off jet skis | There are records of them knocking boaters off of jet skis. |
| Their voices do not carry far, and Animal Diversity Web ties that to a straight trachea, the windpipe | the sounds are not far-reaching due to their straight trachea |
| An adult measures 144 to 158 cm long, with a wingspan of 2 to 2.5 metres | Mute swans are large birds, measuring 144 to 158 cm. The wingspan is 2 to 2.5 meters. |
| some swans have been seen with as many as four mates | some have been observed to have as many as four mates |
| They breed in the British Isles, north central Europe and north central Asia | Mute swans breed in the British Isles, north central Europe and north central Asia. |
| dangerLevel: Medium | Blows from their powerful wings can be especially painful. (note: task #1114: Medium: can injure, rarely seriously) |
| dangerLevel: Medium | There are records of them knocking boaters off of jet skis. |