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Mergansers sensitive to health of wetlands
On a recent visit to Squamish I was delighted to visit an area as yet unknown to me.
Paradise valley is northeast of Squamish and is home to the Tenderfoot Creek fish hatchery.
The hatchery is surrounded by old growth forest and has a wonderful network of ponds, streams and fast flowing rivers.
I was treated to a rare sight in one small pond close to the hatchery when a mated pair of common mergansers drifted by.
There are three species of mergansers: the hooded, red breasted and the largest, the common merganser.
Common mergansers are found across North America.
In the east, they migrate during the winter but in our local areas, many are year-round residents.
These diving ducks have a habitat that includes rivers, estuaries and sheltered shorelines. They can also be found in small lakes and are at home in salt or fresh water with the exception of the young which are only raised in freshwater.
These mergansers’ are often found in local areas, a favorite spot is Miracle Beach Park where they can be seen floating down the river then making the return trip as they fish their way back upstream.
Common mergansers are large ducks ranging in length between 58 and 72 centimetres and weigh up to two kilograms.
The breeding plumage of the male is very striking with a glossy iridescent-green sheen to his black head feathers. His body is pure white with black wing markings and he has a red serrated beak with a black hooked tip.
In contrast, the female plumage is predominately grey but she does have a striking crest of orange-brown feathers which can be raised or lowered.
Both sexes have serrated edges to their beaks enabling the ducks to hold on to their slippery prey.
Predominately fish-eaters, these mergansers also consume a variety of aquatic species including insects, larvae, shellfish, crustaceans and even frogs, small mammals and birds.
Mergansers will also hunt co-operatively; forming a semi-circle they drive the fish into shallow water where they can easily be captured.
At a distance, mergansers are often mistaken for cormorants along the shorelines as they swim low in the water and have a habit of basking in the sun on a rock or piece of driftwood with their wings half open. Mergansers are strong fliers but become clumsy on land they will often fall over when chased by a predator.
Unlike most water ducks, mergansers have a strange choice of nest sites. Primarily tree nesters, they use hollows in decaying trees.
Once again, this emphasizes the importance of the mature forest which so many other birds and mammals rely on for successful breeding.
Like most species of water birds, these ducks produce between eight and 12 eggs reflecting the high mortality rate, few will make it through the first year even if they survive the egg stage.
Life begins precariously as the ducklings have to jump, fly or even be carried out of the nest in the females’ beak.
The ducklings are precotial meaning they are feathered and can swim as soon as they reach the water.
Staying close to their mother, the ducklings will often “hitch” a ride on the mothers back when they tire or feel threatened.
Young ducklings fall prey to eagles, ravens, crows and small mammals, but their biggest threat is loss of habitat which in their case is very specific.
The health of the mergansers is a great indicator of the health of the wetlands as these ducks are susceptible to toxins and pollutants.
Disturbance of the river bed, which is often caused by people removing river rock for landscaping, destroys fish fry habitat and larvae that mergansers rely on.
Watch out for these entertaining ducks along our local rivers and shorelines and if you are ever near Squamish explore some of their hidden treasures.
To report injured or orphaned wildlife please call 250-337-2021 or visit our web site at www.wingtips.org