Leucistic Trumpeter Swan at Bluffers Park in Toronto

 

When Kevin McLaughlin and I saw this swan at Bluffers Park in Toronto on 29 January 2011, we noticed with amazement its bright orange-yellow legs. Since it bore a yellow tag number H11, we surmised it was a Trumpeter Swan. Except for its leg colour, it fit Trumpeter Swan in every respect.

To find out more about this mystery swan, I talked to Harry Lumsden, Ontario’s Trumpeter Swan expert. Harry told me that H11 is a leucistic female Trumpeter Swan, about three years old, spending most of its time at Bluffers Park where it hatched and is the only survivor of its parents. H11’s female parent still lives, however the male parent died recently. Leucism is caused by a single recessive gene that must be carried by both parents.

There are two colour morphs of the Trumpeter Swan, a normal morph and a very rare leucistic or white morph. In Ontario there are currently only two known leucistic Trumpeters out of 652 (winter 2010-2011 inventory): the former pair at Bluffers Park produced one - H11 and a pair at Aurora produced one, which still lives. A pair on Big Rideau Lake produced two or three leucistic offspring about 10 years ago but they are no longer around.

H11 has a normal adult all black bill, however when it was younger, it showed other characters of leucism. As a cygnet during its first year of life its bill was orange-yellow, unlike a normal Trumpeter cygnet’s bill which is dark grayish black towards the tip with pink at the base. When H11 was a cygnet, it had a white plumage and yellow legs and feet, whereas normal cygnets are grey and their legs and feet are grayish pink.

Leucism also occurs in Tundra and Mute Swans. It is very rare in Tundra Swans, which can have pale blue eyes, yellow, orange, pinkish or red legs, and red bills, but is more frequent in Mute Swans, expressing itself as the white morph in cygnets, which remain white as juveniles and adults. The legs and feet of white morph Mute Swan cygnets and juveniles are pinkish tan, and in adults are greyish pink.

Next time you visit Bluffers Park in Toronto, look for this rare leucistic morph of the Trumpeter Swan.

 

Update: In January 2014, a rare leucistic adult Trumpeter Swan was still at Bluffers Park in Toronto

http://www.jeaniron.ca/2014/trumpeter.htm

 

Leucism is the absence of normal pigments, which exposes the underlying colours. It usually applies to plumage but may affect soft parts such as bill, legs and eyes.

 

Acknowledgements

I thank Harry Lumsden for information about leucistic Trumpeter Swans, and Ken Abraham and Ron Pittaway for helpful comments.

 
 

Further Reading

Enright, L. 1994. Ecological significance of the white and grey colour morphs of the Mute Swan. Ontario Birds 12(1):19-26

 

Mitchell, Carl D. and Michael W. Eichholz. 2010. Trumpeter Swan (Cygnus buccinator), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/105doi:10.2173/bna.105

 

This article was first published in the March 2011 Number 213 issue of Toronto Ornithological Club Newsletter