Lately, two males and one female common mergansers have been swimming around on the river at Mt. Pisgah. They are sizable birds at 24-25 inches in length. The male has a long, whitish body with a breast tinged a rosy peach. It has a black back and green-black head. Its bill and feet are red. The female and immature have a gray body with a crested, rufous head that contrasts with a white chin and chest.
Common Mergansers spend the breeding season in northern forested habitats near large lakes and rivers. They are year-round along the Willamette river and are frequently seen at the arboretum. They usually nest within a mile of water in natural cavities or ones made by woodpeckers. So, forests along the river must be preserved in order to mature into trees large enough to allow for a suitable nesting cavity.
Common Mergansers have 1 brood, a clutch size of 6-17 eggs, and an incubation period of 28-35 days. After Common Mergansers are born, the leave nest cavity after a day or two. Even though they are flightless, they fearlessly leap out of the nest cavity (which can be up to 100 feet off the ground), land on the forest floor, and head for the water. From the beginning, they are able to catch all of their own food and start by diving for aquatic insects. Amazingly, they switch over to catching fish at about 12 days old. These bold and independent chicks are still small and vulnerable and will stick close to their mom for protection.
The Common Merganser’s diet consists mostly of fish, and their bills have sharp serrations for grasping this slippery prey. They also eat aquatic invertebrates (including insects, mollusks, crustaceans, and worms), frogs, small mammals, birds, and plants.
They are found throughout a large part of North America. Check out the range map on All About Birds by The Cornell Lab.
See you out there!
