Mergansers commonly nest in holes, cavities or crevices in trees from 15 to 40 feet off the ground. In the absence of suitable trees, they also may nest on the ground under a bush or log, or in a nest box. Nests are lined with weeds, grasses, rootlets and feather down from the female’s chest. Mergansers lay between 9-12 buff-white or ivory-yellow eggs. The female incubates the eggs for 28-32 days, and the young fledge about 65 days after hatching.