CURWOOD: There’s an unusual duck with an unusual name: Histrionicus histrionicus. And as BirdNote’s Mary McCann tells it, the bird, commonly known as the Harlequin, has some unusual behavior as well.

MCCANN: Some ducks don’t sound like ducks at all. Some, like the Harlequin, squeak, earning them the nickname of “sea mice.”

MCCANN: Harlequins are unique in the duck world in other ways as well. Alone among North American waterfowl, Harlequins breed along fast-flowing rivers and streams. Quick and agile in rushing white water, they dive to the bottom of mountain streams for food.

MCCANN: What kind of a name is “Harlequin” for a duck? If you’re lucky enough to spot one of these rare birds in winter, perhaps along a rocky shoreline of Puget Sound in Washington or Penobscot Bay in Maine, you may guess the answer.

MCCANN: Dressed in multi-colored patches, Harlequin is the jester of traditional Italian comedy. The male duck with the jester’s name is just as striking, with his slate-blue feathers and vivid white, black, and chestnut markings.

The rigorous lives of Harlequins require great adaptability – transitioning from fresh water to salt, from meals of caddis fly larvae to crabs and barnacles. Some, in fact, migrate by traveling directly downstream from the mountains to the ocean. Constant, however, is their unmatched ability to swim and feed in the turbulent waters where they live.