Mute Swan

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Mute Swan
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Anserinae
Tribe: Cygnini
Genus: Cygnus
Species: C. olor
Binomial name
Cygnus olor
(Gmelin, 1789)
Range of C. olor      Breeding range     Year-round range     Wintering range
  • Anas olor Gmelin, 1789
  • Sthenelides olor (Gmelin, 1789)
  • Cygnus immutabilis Yarrell, 1838






Mute Swan subfossils, 6,000 years old, have been found in post-glacial peat beds of East Anglia, Great Britain.[8] They have also been recorded from Ireland east to Portugal and Italy,[9] and from France, 13,000 BP (Desbrosse and Mourer-Chauvire 1972–1973).[full citation needed] The paleosubspecies Cygnus olor bergmanni, which differed only in size from the living bird, is known from fossils found in Azerbaijan.[citation needed]

Fossils of swan ancestors more distantly allied to the Mute Swan have been found in four U.S. states: California, Arizona, Idaho and Oregon.[10] The timeline runs from the Miocene to the late Pleistocene, or 10,000 BP. The latest find was in Anza Borrego Desert, a national park in California.[10] Fossils from the Pleistocene include Cygnus paloregonus from Fossil Lake, Oregon, Froman's Ferry, Idaho, and Arizona, referred to by Howard in The Waterfowl of the World as "probably the mute type swan".[11]


"Polish Swan" on the right
Finding food underwater

Adults of this large swan typically range from 140 to 160 cm (55 to 63 in) long, although can range in extreme cases from 125 to 170 cm (49 to 67 in), with a 200 to 240 cm (79 to 94 in) wingspan.[4][12] Males are larger than females and have a larger knob on their bill. On average, this is the second largest waterfowl species after the Trumpeter Swan, although male Mute Swans can easily match or even exceed a male Trumpeter in mass.[4][13] Among standard measurements of the Mute Swan, the wing chord measures 53–62.3 cm (20.9–24.5 in), the tarsus is 10–11.8 cm (3.9–4.6 in) and the bill is 6.9–9 cm (2.7–3.5 in).[4]

The Mute Swan is one of the heaviest flying birds, with males (known as cobs) averaging about 11–12 kg (24–26 lb) and the slightly smaller females (known as pens) weighing about 8.5–9 kg (19–20 lb).[4][14] While the top normal weight for a big cob is 15 kg (33 lb), one unusually big Polish cob weighed almost 23 kg (51 lb) and this counts as the largest verified weight for a flying bird, although it has been questioned whether this heavyweight could still take flight.[15]




Mute swans courting


Unlike Black Swans, Mute Swans are usually strongly territorial with just a single pair on smaller lakes, though in a few locations where a large area of suitable feeding habitat is found they can be colonial. The largest colonies have over 100 pairs, such as at the colony at Abbotsbury Swannery in southern England, and at the southern tip of Öland Island, Ottenby Preserve, in the coastal waters of the Baltic Sea, and can have nests spaced as little as 2 m (7 ft) apart.[16][18] Non-mated juveniles up to 3–4 years old also commonly form larger flocks, which can total several hundred birds, often at regular traditional sites.[19] A notable flock of non-breeding birds is found on the River Tweed estuary at Berwick-upon-Tweed in northeastern England, with a maximum count of 787 birds.[20] Once the adults are mated they seek out their own territories and often live close to ducks and gulls, which may take advantage of the swan's ability to reach deep water weeds, which tend to spread out on the water surface.[citation needed]


Nesting in early spring, Aabach (Greifensee) in Wetzikon, Switzerland

Although this bird can be tame, especially to those who feed it daily, it is aggressive in defence of its nest, and its impressive size make it a formidable adversary for animals as large as a coyote.[citation needed] Most defensive attacks from a Mute Swan begin with a loud hiss and, if this is not sufficient to drive off the predator, are followed by a physical attack. Swans attack by smashing at their enemy with bony spurs in the wings, accompanied by biting with their large bill. The wings of the swan are very powerful, anecdotally reported to exert enough force to break an adult man's leg.[21] Large waterfowl, such as Canada Geese, (more likely out of competition than in response to potential predation) may also be aggressively driven off, and Mute Swans regularly attack people who enter their territory.[22] The cob is also responsible for defending the cygnets while on the water, and will sometimes attack small watercraft, such as canoes, that it feels are a threat to its young. The cob will additionally try and chase the predator out of his family territory, and will keep animals such as foxes and raptors at bay. In New York (outside its native range), the most common predators of cygnets are common snapping turtles.[22] Healthy adults are rarely predated, though canids such as coyotes, felids such as lynxes, and bears can pose a threat to infirm ones (healthy adults can usually swim away from danger unless defending nests) and there are a few cases of healthy adults falling prey to Golden Eagles.[23][24]


Distribution and habitat[edit]

Landing on a canal in Ireland




World population[edit]

Native populations[edit]


The population in the United Kingdom is about 22,000 birds, as of the 2006–2007 winter,[26] a slight decline from the peak of about 26,000-27,000 birds in 1990.[3] This includes about 5,300 breeding pairs, the remainder being immatures.[27] Other significant populations in Europe include 6,800-8,300 breeding pairs in Germany, 4,500 pairs in Denmark, 4,000-4,200 pairs in Poland, 3,000-4,000 pairs in the Netherlands, about 2,500 pairs in Ireland, and 1,200-1,700 pairs in Ukraine.[3]



Introduced populations[edit]

Since being introduced into North America, the Mute Swan has increased greatly in number, to the extent that it is considered as an invasive species. Populations introduced into other areas remain are small, with around 200 in Japan, less than 200 in New Zealand and Australia, and about 120 in South Africa.[2]

North America[edit]

The Mute Swan was introduced to North America in the late 19th century. Recently, it has been widely viewed as an invasive species because of its rapidly increasing numbers and adverse effects on other waterfowl and native ecosystems. For example, a study of population sizes in the lower Great Lakes from 1971 to 2000 found that Mute Swan numbers were increasing at an average rate of at least 10% per year, doubling the population every seven to eight years.[32] Several studies have concluded that Mute Swans severely reduce densities of submerged vegetation where they occur.[33]


The status of the Mute Swan as an introduced species in North America is disputed by the interest group "Save The Mute Swans".[37] They assert that Mute Swans are native in the region and therefore deserving of protection. They claim that Mute Swans had origins from Russia and cite historical sightings and fossil records. These claims have been rejected as specious by the U.S. Department of the Interior.[35]

New Zealand[edit]


Cultural references[edit]


  2. ^ a b c d e del Hoyo, J., et al., ed. (1992). Handbook of the Birds of the World 1. Barcelona: Lynx Edicions. pp. 577–78. ISBN 84-87334-10-5. 
  5. ^ Cheng, Tso-hsin (1987). A Synopsis of the Avifauna of China. Beijing: Science Press. pp. 48–49. ISBN 3-490-12518-5. 
  8. ^ Northcote, E.M. (1981). "Size difference between limb bones of recent and subfossil Mute Swans (Cygnus olor)". J. Archeol. Sci. 8 (1): 89–98. doi:10.1016/0305-4403(81)90014-5. 
  9. ^ Palmer, R.S. (1976). Handbook of North American Birds 2. New Haven: Yale University Press. 
  10. ^ a b Jefferson, G.T. (2005). Fossil Treasures of the Anza-Borrego Desert. p. 153. 
  11. ^ The Waterfowl of the World. pp. 262–265. 
  13. ^ del Hoyo, et al, Handbook of the Birds of the World. Volume 1: Ostrich to Ducks (Handbooks of the Birds of the World). Lynx Edicions (1992), ISBN 978-84-87334-10-8
  16. ^ a b c Cramp, S., chief editor (1977). The Birds of the Western Palearctic. Oxford: Oxford University Press. ISBN 0-19-857358-8. 
  20. ^ "The Berwick Swan and Wildlife Trust". 
  21. ^ [1]
  22. ^ a b "Mute Swan". New York Department of Environmental Conservation. Retrieved 2012-05-03. 
  23. ^ "ADW: Cygnus olor: INFORMATION". Retrieved 2012-05-03. 
  24. ^ Watson, Jeff (2011). The Golden Eagle: Second Edition. ISBN 978-0=30017-019-1 Check |isbn= value (help). 
  25. ^ Dement'ev, G.P.; Gladkov, N.A. (1967). Birds of the Soviet Union IV. U.S. Fish & Wildlife Translation. 
  26. ^ Austin, G.; Collier, M.; Calbrade, N.; Hall, C.; & Musgrove, A. (2008). Waterbirds in the UK 2006/07. Thetford: Wetland Bird Survey. ISBN 978-1-906204-33-4. 
  27. ^ Baker, H. et al. (2006). "Population estimates of birds in Great Britain". British Birds 99: 25–44. 
  28. ^
  29. ^ a b
  32. ^ Petrie, Scott A.; Francis, Charles M. (2010). "Rapid increase in the lower Great Lakes population of feral mute swans: a review and a recommendation". Wildlife Society Bulletin 31 (2): 407. 
  33. ^ Allin, Charles C.; and Husband, Thomas P. (September 2003). "Mute Swan (Cygnus olor) impact on submerged aquatic vegetation and macroinvertebrates in a Rhode Island coastal pond". Northeastern Naturalist 10 (3): 305–318. doi:10.1656/1092-6194(2003)010[0305:MSCOIO]2.0.CO;2. ISSN 1092-6194. 
  34. ^ Williams, Steve. "Finding of No Significant Impact and Final Environmental Assessment for the Management of Mute Swans in the Atlantic Flyway" (PDF). Federal Register 68 (152): 47085. 
  37. ^ "Mute Swan Advocacy". Mute Swan Advocacy. Retrieved 2012-05-03. 
  39. ^ British Monarchy website regarding swan upping and the Crown's ownership of Mute Swans.
  40. ^ "Swan Watch: The Bishop's Swans". Retrieved 2013-09-04. 

External links[edit]