Cygnus olor

Taxonomy

Assessment Information

Geographic Range

Habitat and Ecology

Threats

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	ANSERIFORMES	ANATIDAE

Scientific Name:

Cygnus olor

Species Authority:

(Gmelin, 1789)

Common Name/s:

English

–

Mute Swan

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Published:

2009

Assessor/s:

BirdLife International

Reviewer/s:

Bird, J., Butchart, S.

Justification:
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History:

2008	–	Least Concern
2004	–	Least Concern

Geographic Range [top]

Countries:	Native: Afghanistan; Albania; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; China; Croatia; Cyprus; Czech Republic; Denmark; Estonia; Finland; France; Germany; Greece; Hungary; India; Iran, Islamic Republic of; Iraq; Ireland; Israel; Italy; Japan; Kazakhstan; Korea, Democratic People's Republic of; Korea, Republic of; Kyrgyzstan; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Mongolia; Montenegro; Netherlands; Norway; Pakistan; Poland; Romania; Russian Federation; Russian Federation; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Taiwan, Province of China; Turkey; Turkmenistan; Ukraine; United Kingdom; Uzbekistan Introduced: Australia; Canada; Faroe Islands; Iceland; New Zealand; Singapore; South Africa; United States Vagrant: Bahrain; Bermuda; Egypt; Jordan; Lebanon; Libyan Arab Jamahiriya; Malta; Morocco; Oman; Palestinian Territory, Occupied; Portugal; Syrian Arab Republic; Tajikistan; United Arab Emirates
Range Map:	Click here to open the map viewer and explore range.

Countries:

Native:

Afghanistan; Albania; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; China; Croatia; Cyprus; Czech Republic; Denmark; Estonia; Finland; France; Germany; Greece; Hungary; India; Iran, Islamic Republic of; Iraq; Ireland; Israel; Italy; Japan; Kazakhstan; Korea, Democratic People's Republic of; Korea, Republic of; Kyrgyzstan; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Mongolia; Montenegro; Netherlands; Norway; Pakistan; Poland; Romania; Russian Federation; Russian Federation; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Taiwan, Province of China; Turkey; Turkmenistan; Ukraine; United Kingdom; Uzbekistan

Introduced:

Australia; Canada; Faroe Islands; Iceland; New Zealand; Singapore; South Africa; United States

Vagrant:

Bahrain; Bermuda; Egypt; Jordan; Lebanon; Libyan Arab Jamahiriya; Malta; Morocco; Oman; Palestinian Territory, Occupied; Portugal; Syrian Arab Republic; Tajikistan; United Arab Emirates

Range Map:

Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour Truly wild populations of this species are migratory (particularly where displaced by cold weather)^{1, 6} although European and feral populations are essentially sedentary^{1, 4, 5, 6} or only locally migratory or nomadic^{5, 6}. The species breeds during the local spring^{1, 2}as isolated pairs in well-defended territories¹. After breeding the adults may gather in large concentrations of thousands or more^{3, 4} on selected waters³ (non-breeders in northern Europe migrating to such gatherings⁶) between July and August⁵ to undergo a flightless moulting period lasting for 6-8 weeks². Although not noticeably sociable in many areas during the winter⁴ the species may flock in groups of several thousands on favoured waters^{3, 4, 5}. Habitat The species inhabits a variety of lowland freshwater wetlands¹ such as shallow lakes², ponds³, lagoons, marshes¹, reedbeds^{1, 6} and slow-flowing rivers² (showing a preference for clean, weed-filled streams over larger, polluted rivers)⁴. It is also common on artificial waterbodies such as reservoirs, gravel-pits, ornamental lakes¹, ditches⁶ and canals⁵, and will graze on grassland and agricultural land (e.g. arable cereal fields)². Moulting congregations of adults and non-breeders⁶ may also utilise brackish or saline habitats⁴ including brackish marshes², estuaries and sheltered coastal sites¹ (e.g. brackish lagoons² and bays³). Diet Its diet consists predominantly of leaves and the vegetative parts of aquatic plants^{1, 4} and grasses¹ as well as algae⁴ and grain¹, occasionally also taking small amphibians^{1, 4} (frogs, toads and tadpoles)⁶ and aquatic invertebrates (e.g. molluscs, insects and worms)^{1, 4}. Breeding site The nest is a large mound of aquatic vegetation^{1, 2} placed close to or floating on shallow water^{1, 2} or amongst reeds¹. Breeding pairs often re-use nesting sites from previous years if the it was successful⁴. Management information The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK resulted in an increase in the growth of submerged aquatic macrophytes and in turn led to an increase in the winter use of the habitat by the species⁸. The removed fish (dead or alive) were sold to generate funds⁸. A control of the breeding output of the species (brood reduction) carried out in the Wylye Valley, UK to try to alleviate the species's negative impacts on fisheries (e.g. by overgrazing submergent riverine vegetation) was found to be ineffective as it had an insignificant impact on local population sizes (possibly due to immigration from surrounding areas)¹⁵.
Systems:	Terrestrial; Freshwater; Marine

Habitat and Ecology:

Behaviour Truly wild populations of this species are migratory (particularly where displaced by cold weather)^{1, 6} although European and feral populations are essentially sedentary^{1, 4, 5, 6} or only locally migratory or nomadic^{5, 6}. The species breeds during the local spring^{1, 2}as isolated pairs in well-defended territories¹. After breeding the adults may gather in large concentrations of thousands or more^{3, 4} on selected waters³ (non-breeders in northern Europe migrating to such gatherings⁶) between July and August⁵ to undergo a flightless moulting period lasting for 6-8 weeks². Although not noticeably sociable in many areas during the winter⁴ the species may flock in groups of several thousands on favoured waters^{3, 4, 5}. Habitat The species inhabits a variety of lowland freshwater wetlands¹ such as shallow lakes², ponds³, lagoons, marshes¹, reedbeds^{1, 6} and slow-flowing rivers² (showing a preference for clean, weed-filled streams over larger, polluted rivers)⁴. It is also common on artificial waterbodies such as reservoirs, gravel-pits, ornamental lakes¹, ditches⁶ and canals⁵, and will graze on grassland and agricultural land (e.g. arable cereal fields)². Moulting congregations of adults and non-breeders⁶ may also utilise brackish or saline habitats⁴ including brackish marshes², estuaries and sheltered coastal sites¹ (e.g. brackish lagoons² and bays³). Diet Its diet consists predominantly of leaves and the vegetative parts of aquatic plants^{1, 4} and grasses¹ as well as algae⁴ and grain¹, occasionally also taking small amphibians^{1, 4} (frogs, toads and tadpoles)⁶ and aquatic invertebrates (e.g. molluscs, insects and worms)^{1, 4}. Breeding site The nest is a large mound of aquatic vegetation^{1, 2} placed close to or floating on shallow water^{1, 2} or amongst reeds¹. Breeding pairs often re-use nesting sites from previous years if the it was successful⁴. Management information The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK resulted in an increase in the growth of submerged aquatic macrophytes and in turn led to an increase in the winter use of the habitat by the species⁸. The removed fish (dead or alive) were sold to generate funds⁸. A control of the breeding output of the species (brood reduction) carried out in the Wylye Valley, UK to try to alleviate the species's negative impacts on fisheries (e.g. by overgrazing submergent riverine vegetation) was found to be ineffective as it had an insignificant impact on local population sizes (possibly due to immigration from surrounding areas)¹⁵.

Systems:

Terrestrial; Freshwater; Marine

Threats [top]

Major Threat(s):	The species suffers heavy losses from lead poisoning due to ingested lead fishing weights^{1, 11}, lead shot⁹ and lead contaminated sediments from mining and smelting activities¹³. Heavy losses have also been recorded from local incidences of copper poisoning¹⁴. The ingestion of or entanglement in fishing lines and/or hooks can also cause severe injury or mortality¹¹ as can collisions with overhead lines¹. The species may be threatened by future oil spills (which can cause death by oil saturation)¹². The species is also susceptible to avian influenza⁷ (e.g. strain H5N1)¹⁰ so may be threatened by future outbreaks of the virus.

Major Threat(s):

The species suffers heavy losses from lead poisoning due to ingested lead fishing weights^{1, 11}, lead shot⁹ and lead contaminated sediments from mining and smelting activities¹³. Heavy losses have also been recorded from local incidences of copper poisoning¹⁴. The ingestion of or entanglement in fishing lines and/or hooks can also cause severe injury or mortality¹¹ as can collisions with overhead lines¹. The species may be threatened by future oil spills (which can cause death by oil saturation)¹². The species is also susceptible to avian influenza⁷ (e.g. strain H5N1)¹⁰ so may be threatened by future outbreaks of the virus.

Citation:	BirdLife International 2009. Cygnus olor. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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