The Common Merganser

June 29, 2022

One of the many projects I am involved with on the Willits Bypass Mitigation Lands is installing video cameras in locations where we can capture some wildlife activity. This duty is shared with my colleague and awesome wildlife observer, Jacob Stubberfield. He has taught me a lot about how and where to set up these cameras for success. Still, there are times when I think I have a good spot and get nothing. For every thirty videos there may be two good ones. This week I brought the cameras back and began looking through the footage with excitement and anticipation about what I would find.

The first few videos were mostly Wild Turkeys which was a little disappointing, but also entertaining, as they always are doing some antics that make me laugh. They seem to really love being on camera. Then I came across an interesting series of videos showing the Common Merganser mother and ducklings that I had been seeing on Outlet Creek. The videos revealed that the ducklings had grown quite a bit since the last time I had seen them and that all five had survived! I decided to write this blog about these beautiful and common diving ducks in our area.

Common Mergansers, Mergus merganser, are as most ducks, sexually dimorphic, which means the males and females look different. During the breeding season, the male Merganser is mostly white with an iridescent dark green head. The wings have large white wing patches with dark black shoulders and the tail is grey. One of the most spectacular features of the male is its bright red pointy bill. The female has a red bill too but not quite as bright. Merganser bills are serrated and hooked at the tip. The female is mostly grey with a cinnamon red head that has a crest, and her belly is white. Both sexes have red legs to match their red bills. All the juveniles look like the mom but without a crest. During the late winter, males will begin to get their breeding plumage and females will develop the crest. Common Mergansers are found in many freshwater habitats such as rivers and lakes. Although they prefer freshwater, they can also be found in bays and along the coast. They are known as ‘gooseander’ in Europe and Asia.

Common Mergansers nest mostly in cavities, using natural tree hollows, woodpecker holes, caves, holes in banks, and human-made duck boxes. They can nest as high as 100 feet in a tree which is significant because like Wood Duck ducklings, they only spend a short time in the nest, 1 to 2 days before leaping out to join their mom on the lake or river. The young are not fed by their mom at all after leaving the nest but immediately begin hunting and eating invertebrates such as mayfly larvae, caddis fly larvae, crustaceans, and worms on their own. After twelve days they begin to hunt fish. I read this in all the research articles and wonder if their bills grow long enough and develop stronger serration at this point to grasp the slippery fish, or maybe their skill level is better. Adult birds prefer to eat fish but also eat aquatic life such as frogs, small mammals, birds, and plants. Mergansers use their bills to probe under rocks and in sediments.

Common Mergansers can lay as many as 17 eggs and sometimes will spread them out in other birds’ nests, probably to increase the survival rates of the young. They are known to practice ‘creching,’ where ducklings from many mothers are grouped together and cared for by one adult. A photographer captured a photo of a Common Merganser hen with 75 ducklings following her on Lake Bemidjii in Minnesota! You can read about it in this Audobon article:

When I walk down to the water on the south end of Outlet Creek, I often see the Common Merganser and her five ducklings. The videos provide us a window into their world and give us a clearer picture of their development and behavior.