It is also possible that arctic char and salmon roe are important foods for breeding harlequins in Labrador. In winter, these incredible small ducks dive for food among the rugged, surf-pounded rocks. When observing them, you cannot help but wonder why they are not crushed by the surf. They dive, and just when you believe they are in trouble, they pop up to the surface like corks and get ready to dive again. They feed there because these turbulent and oxygen-rich waters are rich in invertebrates.
Harlequins search the ocean bottom and among seaweed for crabs, snails and fish roe.
In spring, harlequins congregate at river mouths and estuaries and breed along turbulent streams. Harlequin ducks may become sexually mature at two to three years of age, but like many seaducks, may not successfully raise young until they are older. They nest under bushes or in a cavity among rocks. The nest is lined with grasses and down. Five or six cream to pale buff coloured eggs are laid during May to July.