The Red-breasted Merganser nests on the ground, well hidden in dense vegetation, under a bush, in a rock crevice or among stones, often near water on an archipelago island. The female normally lays 8–10 eggs and incubates alone for just over four weeks. The newly hatched young are quickly taken to the water, where they swim and dive from the very first day. Females with broods sometimes join together, so that several broods form a combined group guarded by several adult birds.