Re-posted from 2021
Thud. Thud. Thud. You are walking through the trees near Redfish Lake. The beams of sunlight are reflecting off the water and the breeze is floating effortlessly through the branches. As you are making your way through the stands of pines, you begin to hear the noise of something dropping onto the forest floor. You can hear the rustling of the pine needles when the object hits the ground. Something you did not expect was the sound of a duck quacking in the middle of the thumping and bumping sounds. Curiosity inspires you to move farther forward, and the sight is awe inspiring. On the forest floor, a bird with a rusty colored head, smoky gray body, and a crimson bill calls up to a cavity in a nearby tree. By her side, young chicks stand near that look as though they are miniature versions of her. About 10 feet above your head, even more chicks are leaping from the safety of their nest cavity and glide through the air until they collide with the hard ground and scamper closer to their mother. These birds are called Common Mergansers, and this is the story of how these magnificent ducks bring their ducklings into the world.
Common Mergansers are a large duck that can be identified by their vibrant coloration and their slender, sleek bill. They regularly spend their time near bodies of water because they prey mainly on fish and aquatic invertebrates. As a result, they are a “frequent flyer” to northern lakes and rivers. Idaho is one of the few states that mergansers are year-round residents, as opposed to migrants that move through. This means that the people of this state can get a firsthand look at the entire process of nesting, egg laying, and chick rearing of this unique species.
A male (left) and female (right) Common Merganser. Credit: “Common Mergansers” by U. S. Fish and Wildlife Service – Northeast Region is marked with Public Domain Mark 1.0.
Male mergansers create elaborate courtship displays to win the females over, similar to a flashy marriage proposal. These displays may include the male swimming in circles around the female, stretching out his neck, and making soft calls toward her. After the male and female have mated, the male goes on his way and does not help out any further when it comes to incubation or caring for the ducklings. The female will choose a nesting site that is less than about a mile from water, because this is where she gets all of her food. The nest is often a hole or cavity in a tree, but it can also be on the ground if there are no available cavities in the area. On average, the female merganser will lay 8-12 eggs in the summer months of May and June. From that point, she will incubate, or sit on, the eggs for about 31 days. After that month is up, the chicks that hatched will spend a day or two in their nest before venturing out into the world in a dramatic fashion. The mother will stand at the base of their nest in the trees and call for her ducklings to come to her. One by one, the ducklings fling themselves through the air until they have made impact with the ground and have made it back to their mother’s side.
The mother merganser then leads her young to the water. Even though she cares for her ducklings for the next several weeks, she does not help them find food and they are responsible for feeding themselves. After the first few days of living on the water, the ducklings become skilled divers, just like their parents. Many species in the animal world will care for their young until they are ready to leave their parents, but the Common Merganser does the opposite; the mother abandons her young before they are able to fly. Since they have been catching their own food from their first few days, they can survive without their mother when she does leave. The ducklings often join other groups of ducklings until they can fly and join the adult birds. At around 2-3 months of age, the ducklings are strong enough to take their first flights, and the cycle of reproduction repeats when the ducks reach maturity at two years of age.
Konner Kirkwood was a Naturalist for SIHA 2021. He enjoys spending time by the water to watch the fish and wildlife that rely on the waterways of the Sawtooth National Recreation Area. (Photos updated by SIHA, May 2024).