Birds of the Glebe, The Eye-catching Hooded Merganser

Hooded mergansers, fast swimming and flying ducks, migrate south in winter, stopping here on their way. This monogamous pair was resting in Brown’s Inlet.   Photo: Jeanette Rive

The Eye-catching Hooded Merganser

By Jeanette Rive

We are fortunate to have many rivers, lakes and ponds nearby where we can see a wide variety of water birds year-round. In our neighbourhood alone, there’s Dow’s Lake, the Rideau Canal, Brown’s Inlet, Patterson Creek and the small creeks in the Arboretum. These waters serve as a staging ground for flocks of migrating birds heading south or returning north.

Twice a year, we are treated to a selection of spectacular ducks which breed further north and retreat south when northern waters freeze. Among them is the Hooded merganser. The male’s dramatic black and white head and often raised crest makes it easy to spot and identify. Other visitors here include the Northern shoveller with its large bill, Goldeneyes and Common mergansers.

The Hooded merganser is one of three mergansers found in our area. The larger Common merganser and the rarer Red-breasted merganser are equally distinguished. The Hooded merganser is the only one native to North America and is the smallest of the three. It is a diving duck, unlike mallards and Wood ducks which are dabbling ducks, and it hunts its prey by swimming on the surface with its head in the water. When it spots a fish, it dives underwater to chase and catch the target with its serrated bill. It resurfaces to swallow, turning the fish so it goes down headfirst to avoid injury from a spiny fin facing the wrong way.

When diving, it protects its eyes by closing its third eyelid, called a nictitating membrane. Nature’s safety goggles, this slightly opaque membrane, which most birds have, also protects the eyes of fast-flying birds, such as the Peregrine falcon, from the wind and dust and from the claws of struggling prey.

A diving duck’s legs are further back on its body, compared to those of a dabbling duck. This is better for paddling, but it makes it very awkward to walk on land. To take off from the water, it builds up speed by almost running on the surface of the water. A large, heavy bird like a loon needs to “run” about 500 metres on the water to get up enough speed to take off. Watching a loon take off makes one hold one’s breath, willing it to make it over the trees at the end of a lake!

The Hooded merganser is both a fast swimmer and a fast flyer – it can reach a speed of 50 kph in the air. It is a short-distance migrant, found over most of North America, only flying far enough south to find ice-free water.

Hooded mergansers are sexually dimorphic, meaning the sexes are very different in appearance: the drake is much more colourful, though both are crested. They are monogamous – the male courts the female by swimming around her with elaborate head bobbing and swinging while emitting a low, frog-like, gravelly sound which can be heard up to a kilometre away. If he’s acceptable, she will bob her head and raise her tail for mating, which takes place in the water.

As with Wood ducks, they nest in tree cavities up to 20 metres high. The nest is lined with twigs and forest vegetation and as the eggs get laid, the female will pluck down from her belly to add to the warmth. Seven to 15 eggs may be laid, but she will only start incubating them when the last one has been laid, so that they all hatch at the same time after about 30 days. The day after hatching, she will leave the nest, check the surrounding area for safety and call her little chicks to jump down. They will then all head to the nearest water where the chicks are able to swim and forage immediately, although they will stay close to the mother for warmth and sssafety. Mergansers will often return to the same area to breed, and the female may already start scouting for next year’s nesting spot at the end of the breeding season.

The migrants have moved on. The birds that spend the winter here will need our feeders full. Watching the birds at our feeders is one of the joys of winter. Happy gazing!

Jeanette Rive is a Glebe bird enthusiast and regular Glebe Report contributor.

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