Mute Swan

 Mute Swan are most commonly found in the Great Lakes terrain of Ontario and the U.S, the Atlantic coast of the U.S., and Southern British Columbia (GovofCan).

Swans are known for having lifelong mates, however they will choose a new mate if their partner dies. Interestingly, the age and sex of the Mute Swan determines who’s territory the pair will join. A male that is choosing a new mate will join the female’s territory if she is older or the female will join the male’s territory if she is younger (AllAboutBirds).

Mute swans will engage in a slow courtship ritual where the pair will bow their heads to each other, dunk their heads in the water in a synchronized fashion while making hissing sounds (BeautyOfBirds).

It is up to the male to find an acceptable location for the female to ultimately choose. The best location is based on the accessibility of food and nesting materials. Mute swans will chose their nest to be made on elevated vegetation surrounded by water (AllAboutBirds). The male will find nesting material (twigs, grasses and aquatic vegetation) and give it to the female who will build the nest and use her body to mold a space to lay eggs. Mute swans’ nests can also be lined with feathers and down (BeautyOfBirds).

Females will lay 2-5 eggs during clutch and will incubate for 34-41 days (AllAboutBirds). The male will defend the nest from any predators and will occasionally lay on the eggs for short periods if the female is absent either bathing, preening or feeding (BeautyOfBirds). 

The Mute swans young are called cygnets (Conover et al., 1999). They have black bills and feet and display a fluffy and grey plumage (AllAboutBirds). Mute Swans will carry cygnets on their back,  keeping the cygnets safe from predators while providing a dry warm place to sleep. Mute swans can adopt very aggressive behavior if they think their young/nest is in danger (AllAboutBirds).

Mute Swans are an invasive species to North America and pose risks to native wildlife and habitats. Mute swans have a large diet and require lots of food to sustain their large size. By overgrazing, these swans damage native wetland habitats. Mute swans have low conservation concern due to having little predator risks (AllAboutBirds). Their population is growing quickly and Partners in Flight has reported a 400,000 global breeding population (AllAboutBirds). A single Swan can eat up approximately 8 pounds (4kg) of aquatic plants per day, this can greatly affect wetlands ecosystems (GovofCanada).

 Their intense feeding habits also reduce food available for other native species. The Mute Swan is known to be very territorial and display extremely defensive behavior such as threat postures, pecking, trampling of native eggs and nests and physical attacks (Reynolds, 1972). This behavior often deters many native bird species such Mallards, Canada Geese and Trumpeter Swans away from their natural habitats (GovOfCan).  

• Males and females are normally difficult to distinguish between. During breeding season the male black knob on his bill will swell to become larger than the females (AllAboutBirds).
• The oldest Mute Swan recorded in North America was 26 years old (AllAboutBirds).
• The national bird of the Kingdom of Denmark is the Mute Swan (WhatBird).
• In the classic Swan Lake ballet, Princess Odette get transformed into a Mute Swan (JustFunFacts).
• North American Mute Swans typically don’t migrate (AllAboutBirds).

As mentioned above, the abundance of Mute Swans population along with their diverse and heavy diet have a huge impact on ecological system (Charles et al., 2003). Aquatic plants are an important habitat for many fish species to provide spawning locations and food resources (Guillaume et al., 2014). They also are critical for reducing algae blooms and improving water quality (Guillaume et al., 2014). 

 A 2008 study from The Journal of Wildlife Management set out to determine which aquatic vegetation important to native waterfowl were most impacted by the grazing of Mute Swans. This was  based off of age, sex, and seasonal  differences in the Mute Swans diet. 356 Mute Swans were collected from Lake St. Claire, Detroit River, and Long Point-Lake Erie throughout every season during 2001, 2002 and 2004 (Bailey et al., 2008) . They were sent to a laboratory at Bird Studies Canada where their digestive tracts were removed and food contents extracted from their esophagus and proventriculus. (Bailey et al., 2008) . The diets were sorted as identified genus or species, and unidentified (leaves, stems, seeds, decaying matter) (Bailey et al., 2008) . They were able to include 132 Mute swans to the statistical data (Bailey et al., 2008).

There were 10 major food items found which included slender naiad, coontail, common waterweed, pondweed spp, stone-worts, wild rice, wild celery, arrowhead, tubers, milfoil spp., and aquatic invertebrate (Bailey et al., 2008). This study  concluded that there were no seasonal or age differences in the  diet of Mute Swans (Bailey et al., 2008) . There was however sex-related differences in that females consumed a higher amount of pondweed spp and less common waterweed and slender naiad than males. This could be explained by dietary preferences related to female egg production, incubation and brood rearing energy demands (Bailey et al., 2008) .

Their findings suggested that there was substantial overlap with native waterfowl diets, which may imply that there is considerable competition for wetland vegetation (Bailey et al., 2008) . Mute Swans in comparison to native waterfowl  differ in their size, intake rate and energy demands which may be seen in a reduction of grazing by smaller waterbirds due to a depletion of food sources and the aggressive behavior of Mute Swans (Guillaume et al., 2014) .

Bailey, M., Petrie, S. A., & Badzinski, S. S. (2008). Diet of Mute Swans in Lower Great Lakes coastal marshes. Journal of Wildlife Management, 72(3), 726–732. https://doi.org/10.2193/2007-133

Charles C. Allin and Thomas P. Husband “MUTE SWAN (CYGNUS OLOR) IMPACT ON SUBMERGED AQUATIC VEGETATION AND MACROINVERTEBRATES IN A RHODE ISLAND COASTAL POND,” Northeastern Naturalist 10(3), 305-318, (1 September 2003). https://doi.org/10.1656/1092-6194(2003)010[0305:MSCOIO]2.0.CO;2

Conover, M. R., & Kania, G. S. (1999). Reproductive Success of Exotic Mute Swans in Connecticut. The Auk, 116(4), 1127–1131. https://doi.org/10.2307/4089693

Guillaume, G., Matthieu, G., Pierre, D.R. et al. Effects of mute swans on wetlands: a synthesis.Hydrobiologia 723, 195–204 (2014). https://doi.org/10.1007/s10750-013-1704-5

Interesting facts about mute swans: Just fun facts. Just Fun Facts | Fun and interesting site. (2019, December 2). Retrieved October 17, 2022, from https://justfunfacts.com/interesting-facts-about-mute-swans/

Mute swan overview, all about birds, Cornell Lab of Ornithology. Overview, All About Birds, Cornell Lab of Ornithology. (n.d.). Retrieved October 17, 2022, from https://www.allaboutbirds.org/guide/Mute_Swan/overview

Mute swan – Cygnus Olor. Observation.org. (n.d.). Retrieved October 17, 2022, from https://observation.org/observation/76096036

Mute swans: Breeding / reproduction. Beauty of Birds. (2022, September 21). Retrieved October 17, 2022, from https://beautyofbirds.com/mute-swan-breeding/

Mute swans (Cygnus Olor): Nantucket Conservation Foundation. Nantucket Conservation Foundation | Preserving the Island for Everyone. (2018, December 19). Retrieved October 17, 2022, from https://www.nantucketconservation.org/mute-swans-cygnus-color/

Mute swan. Whatbird.com. (n.d.). Retrieved October 17, 2022, from Mute Swan – Whatbird.com.

olsxBene. (2015, December 5). Mute Swan Courtship dance. YouTube. Retrieved October 17, 2022, from https://www.youtube.com/watch?v=egUCF1emVWE

Reynolds, C. M. (n.d.). Mute swan weights in relation to breeding. Wildfowl. Retrieved October 17, 2022, from https://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/443/443

Singh, B. N. (2017, February 6). Mute swan. Flickr. Retrieved October 17, 2022, from https://www.flickr.com/photos/bnsingh/32746283065/

. UWL Website. (n.d.). Retrieved October 17, 2022, from http://bioweb.uwlax.edu/bio203/2010/aspenson_kris/reproduction.htm

Wikimedia Foundation. (2022, September 22). Mute swan. Wikipedia. Retrieved October 17, 2022, from Mute swan – Wikipedia

Yorkshire Swan & Wildlife Rescue Hospital. (2021, March 22). Nesting swans. Twitter. Retrieved October 17, 2022, from https://twitter.com/swan_rescue/status/1374053295547891712