The White-winged Scoter breeding range extends from the Ontario/Manitoba border, west just north of the US boarder to central British Columbia and north along the treeline to the Alaskan interior. The core breeding area is the boreal forest of northwestern Canada, primarily the Northwest Territories, with approximately 60% of the continental scoter population. Through limited leg band data, it's been shown that White-winged Scoters from the Atlantic coast tend to breed more north and east in this breeding range, while Pacific populations migrate more south and west. Breeding does not occur until the birds are at least 2 years old with birds in the first year, and some two year old birds, remaining close to their winter ranges. The birds pair primarily on wintering grounds however pairing can also occur on the breeding grounds. Courtship displays are minimal compared to other scoter species. The male will often perform a Neck-Erect-Forward Display where he stretches his neck out at a 65oangle so it appears thick, while swimming at a high rate of speed. This display is usually performed by a single male towards a pair. Paired birds perform courtship behavior prior to copulation, which includes preening and false drinking. Nests are found in dense vegetation usually far from water (up to 0.5 miles). Females return to their natal area year after year and will sometimes use the same nest bowl. While generally non-colonial in the boreal forest, White-winged Scoters have been found to nest in high densities in the prairie and parkland regions. In these situations, there can be competition for nest sites with females "dumping" eggs in other White-winged Scoter nests. The male will defend the female during egg laying but leaves once incubation begins. She will lay an average of 9 to 10 eggs at a rate of approximately 1.5 eggs per day. Incubation takes from 25 to 30 days from the time the last egg is laid. The female usually broods the ducklings in the nest for up to a day before walking to water and swimming to brood-rearing areas. Ducklings are able to dive to avoid predators, such as gulls, and to feed on their own. When attacked by a predator, commonly a gull, alarm calls by the female result in the ducklings diving or moving close to the female. The female will brood and protect her young aggressively for 1 to 3 weeks, after which time she abandons her young. Abandoned young often form aggregate broods of 15 to 40 but can form groups of over 100. Ducklings take approximately 70 days to reach fledging stage. Overall, information about duckling survival is limited and varied as there have been very few studies, but overall it appears to be low, 1.4% to 10%.