Rocket Ducks

Common Merganser females (Mergus merganser)

On Friday afternoon these three birds were tearing up the North Basin. Several people told me about them before I could spot them. Then I couldn’t miss them. Various scaup, coot, and wigeons sat on the water here and there, hardly moving. But these red-headed birds moved like rockets. They rose out of the water and half paddled, half winged their way forward in mad dashes. They changed direction suddenly. Sometimes they converged on the same spot and made a big splash, like kids chasing a ball in a pool. They moved faster than cormorants, faster than anything on the water. I was amazed at their energy. I had never seen them before. They’re said to be very common ducks across this country and the world, but to my local eyes they’re newcomers. They’re Common Mergansers (Mergus merganser), and all three in the video are females. The females have rusty red heads. The males’ heads are black with green iridescence.

These Mergansers are fish-eating ducks. Their narrow bills have sawtooth edges and a sharp point for grabbing and holding fish. They’ll cruise on the water with their heads below the surface, looking for prey. Then they dive. Underwater, they paddle with both legs at the same time like a dolphin with its tailfin, giving them great speed. They may eat their catch before they resurface. When larger groups hunt together, they may form a semicircle and drive fish to shallow waters, the easier to take them. These three hung together as a group but competed with each other, sometimes banging into one another in the process.

They breed up north in a broad front stretching from coast to coast, and similarly across Eurasia. Their key requirement is big trees with holes, either natural or carved by woodpeckers, as much as 100 feet high if available. There the females lay their eggs. A few days after the chicks hatch, Mom calls them out of the nest, and those that survive the fall (they can’t fly yet at all) follow Mom to the nearest water. Once there, they can feed themselves. Usually Dad departed to go molt when the female started sitting on the eggs. She’ll take them, sometimes riding on her back, to bigger waters.

Common Mergansers have complex, unpredictable migration patterns. They’re capable of surviving cold weather so long as their lakes don’t freeze over. Some of them migrate short distances, others go long. No way to tell where these three came from. If they stay, they’ll make the normally placid North Basin a more exciting scene.

Common Merganser females (Mergus merganser)

More about them: Wikipedia Cornell Audubon

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