Hello again, welcome back to animals under threat. Today,
we will be covering a species of bird from the genus Cygnus that was at the
brink of extinction but is making a comeback. It is also called North America’s
heaviest flying bird with males weighing over 26 pounds and the main character
in E. B. White’s 1970 children’s book the Trumpet of the swan. Give a warm
welcome to the trumpeter swan (Cygnus buccinator).
The Trumpeter swan is one of three species of swans that
resides in North America along with the Mute swan (Cygnus olor) which was
introduced and the Tundra Swan (Cygnus columbianus). Trumpeter and tundra swans
look similar to each other, but Trumpeter swans are characterized by their solid
black straight beak and white feathers while Tundra swans have yellow markings
under their eyes (ebird.org, 2020). Male Swans are called the Cob and usually
weigh more and are larger than female swans which are called the Pen (trumpeterswansociety.org,
2020).
Trumpeter Swans by
Jakub Fryš
Trumpeter Swans prefer to live in areas that are shallow
freshwater lakes with lots of aquatic vegetation to feed on. They also need
large areas of open water in order to do their running-take-off. Female Trumpeter
swans also need lake areas with small islands or beaver dams of nesting
(allaboutbirds.org, 2020). Weighing over 26 pounds and 1.8 long in length, the
Trumpeter swans gather at the end of lakes/rivers in order to start their take
off run. During their take off run, the swan will flap its 3m wingspan in order
to take off from the water (Britannica.com, 2018).
Video by Lisbasan
Adult Trumpeter swans mainly feed on aquatic vegetation while
they are swimming, terrestrial grasses and agricultural grains when on land. Young
juvenile swans however feed on insects, small fish and fish eggs and small crustaceans
before changing to a plant-based diet in the first few months. Adults and juveniles
will up-end or dabbling in order to reach food that is underwater which makes
them look like they are upside down and adults will dig into muddy substrates to
reach roots and tubers (Johnson & Lockwood, 2013).
swan
feeding by Rodger Beardmore (above) and silly
swans by Kayo Roy (below)
Trumpeter swans build their nests on a site that is surrounded
by water and is 600m from the shore. The nest is usually built on top of a
beaver/muskrat dam and dens with both parents collecting plant that usually
consist of aquatic vegetation to build the nest (Wells & Wells, 2007). The female
uses her body and bill to shape the nest on top of an aquatic vegetation mound.
The female will lay a clutch of eggs that can range between 4-6, are a creamy
white colour and are incubated for 32-37 days. Young swans are called cygnets and
are covered in grey colour down and can leave the nest after 24 hours to swim
and feed. Adult swans usually mate for life although there have been cases
where if one dies, the other will sometimes take another mate (ebird, 2020).
juvenile
by Greg Hume
This species was once driven close to extinction by
poaching, habitat destruction and lead poisoning. Trumpeter swans were poached
for their feathers which were popular for designing, meat for eating and game
and skin for powder puffs (Johnson and Lockwood, 2013). Destruction of wetlands
that the swans need for feeding and nesting has affected the swan’s population
as they cannot survive without it. Lead poisoning from discarded lead shots also
affected the population as young swans fed on the shots which led to lead
poisoning and death of young swans (Wells & Wells, 2007).
Next time, we will be covering a subspecies of Western
Gorilla and is found near the Cross River, Nigeria.
Johnson, WP, & Lockwood, MW 2013, Texas Waterfowl,
Texas A&M University Press, College Station. Available from: ProQuest Ebook
Central. [26 March 2020].
Wells, JV, & Wells, JVV 2007, Birder's Conservation
Handbook : 100 North American Birds at Risk, Princeton University Press,
Princeton. Available from: ProQuest Ebook Central. [26 March 2020].
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