Surf Scoter

Pair bonds form on wintering and staging grounds, with most pairs established before birds arrive on the breeding grounds in May. The species is considered monogamous, and some observations suggest bonds may persist across multiple years, though this is not confirmed. Males do not breed until around three years of age.

Nest building typically begins in mid-May to early June. The nest is on the ground, well concealed under low tree branches, fallen logs, or in dense grass clumps — often some distance from water but generally upland from marsh vegetation. The female constructs a shallow depression lined with her own down feathers and plant matter: mosses, grasses, spruce and fir needles, twigs, and bark. In one Quebec study, nests averaged 30 cm across, with an interior bowl 17 cm wide and 6 cm deep.

Clutch size is 5–9 eggs, usually around 7. Eggs are creamy white or pale buff, measuring approximately 6.4–6.8 cm long and 4.5–4.8 cm wide. Incubation is by the female only and lasts approximately 28–30 days. The male leaves soon after incubation begins, departing to dedicated moulting sites on the coast.

Ducklings are precocial — downy, with open eyes at hatching — and leave the nest shortly after drying, feeding themselves immediately. The female tends and guards the brood but provides no direct feeding assistance. Because mothers guard rather than actively feed their young, there is little evolutionary pressure against ducklings straying between broods — making brood amalgamation a regular and apparently adaptive behaviour in this species. The female abandons the chicks before they can fly, at approximately 55 days, after which multiple broods often join to form crèches. The species does not renest if a clutch is lost, and studies show strong fidelity to nesting areas across years.

In 2025, a male shot in coastal New Jersey was confirmed to be at least 22 years old — a new longevity record for the species. The bird had been banded as an adult by the Canadian Wildlife Service in Labrador in 2004, meaning it had survived for over two decades while completing annual migrations of more than 3,000 km between breeding and wintering grounds. Surf Scoters typically live for 10–15 years in the wild, with survival rates improving after the first year, when inexperienced birds face the highest mortality.

Mortality causes include hunting (approximately 20,000–25,000 birds shot annually in the US alone), oil spills on wintering grounds, predation (particularly of eggs and ducklings by foxes, ravens, and large gulls), and starvation during severe winters when prey becomes inaccessible. First-year birds are disproportionately vulnerable, particularly during their first southward migration and first winter on coastal foraging grounds.

Compared to other sea ducks, Surf Scoter longevity is broadly similar to that of the Common Eider, which regularly reaches 20+ years in the wild, and somewhat shorter than the Long-tailed Duck, for which records of 28 years exist. The remote breeding range of the Surf Scoter means that survival data are sparser than for many other wildfowl, and true average lifespan in the wild remains incompletely known.

The Surf Scoter is listed as Least Concern on the IUCN Red List, but this status masks a troubling population trajectory. The global breeding population is estimated at 470,000 individuals by Partners in Flight, with Ducks Unlimited placing the total population (including non-breeders) at 600,000–1,000,000. Population size is poorly known due to the species' remote breeding range in the Canadian boreal zone.

Limited survey data suggests a decline of 50–70% since the 1950s–1980s. In Puget Sound — one of the most important and well-monitored wintering sites — the scoter population index has declined by more than 50% since 1994–96, and possibly as much as 78% since 1978–79. Climate modelling projects a further 31% decline by 2080 compared to 1980 levels. Washington State has designated the Surf Scoter as a Species of Greatest Conservation Need.

Primary threats fall into several categories. Oil spills on wintering grounds pose an acute risk, where large concentrations of birds are highly vulnerable; heavy metal and organochlorine contamination compounds this. Coastal habitat is under pressure from loss and degradation of both boreal breeding areas and marine wintering grounds. Commercial shellfish operations overharvest mussel prey, and aquaculture practices actively exclude sea ducks from key foraging areas. Hunting accounts for approximately 20,000–25,000 Surf Scoters shot annually in the US, with the Atlantic Flyway accounting for roughly 80% of the harvest.

Climate change poses a compounding threat through trophic mismatch — altering the timing of snowmelt and prey emergence on breeding grounds — and by shifting herring spawn timing and degrading subtidal foraging habitats. Offshore wind farm development in key Atlantic migration corridors is an emerging concern identified by the Sea Duck Joint Venture's satellite telemetry studies.

The paradox of Least Concern status alongside a 50–70% decline reflects the species' still-broad range and large absolute numbers. Conservation efforts focus on protecting key moulting and wintering sites, monitoring boreal breeding populations, and reducing bycatch and pollution in coastal wintering areas.

In a mixed scoter raft at distance, the male Surf Scoter's head shape is the first thing to fix on: the swollen bill base gives the forehead a steep, wedge-like profile quite unlike the flatter head of a Common Scoter. Once you've picked out that silhouette, the white forehead and nape patches confirm the identification — no other North American scoter shows both. At closer range, the multicoloured bill (orange-red, yellow, white, and a black square spot) is unmistakable.

Separating Surf from White-winged Scoter is straightforward in flight: Surf Scoters are entirely dark-winged on both surfaces, while White-winged shows a bold white secondary patch. On the water, White-winged Scoters are noticeably bulkier, with a more rounded head and a small but visible white eye-patch.

Female and immature Surf Scoters are the trickier proposition. In a flock of female Common Scoters, look for the two whitish face patches (one before the eye, one behind) and the distinctively swollen grey-black bill — both absent in female Common Scoters. Some adult female Surf Scoters also show a faint white nape patch, a feature unique among female scoters. Female Velvet (White-winged) Scoters show a white wing patch in flight, which female Surf Scoters lack entirely. Juveniles are paler below than adults, with less well-defined facial patches, but the bill shape remains a reliable pointer at any age.

Courtship aggregations form on wintering and staging grounds from late winter, often weeks or months before birds depart for the breeding areas. This extended window means that males from across the wintering range compete for females at the same coastal bays and estuaries — a very different dynamic from species that pair up only on arrival at breeding sites. On the Pacific coast, major staging areas such as the Strait of Georgia and Puget Sound host some of the largest and most accessible courtship gatherings of any North American sea duck.

Within these groups, males perform a sequence of ritualised displays more elaborate than those of most other scoters. The sentinel posture — neck stretched vertically upward, bill pointed skyward — advertises the white head patches and colourful bill. This is followed by breast-scooping, in which the male drags his bill rapidly across his chest in a sweeping arc, and by lateral head-shaking that catches the light on the bill's multicoloured surface. Competing males may chase each other across the water in short, splashing rushes, and aerial pursuits of females also occur.

Females signal receptivity through the chin-lift display: head tilted sharply upward, throat exposed, accompanied by a raspy crowing call. Most pair bonds are established before birds arrive on the breeding grounds in May. Once there, the male's role ends quickly — he departs for moulting sites soon after the female begins incubation, taking no part in chick-rearing. The elaborate courtship investment is therefore the male's entire reproductive contribution beyond fertilisation, which may explain why the displays are so visually striking compared to those of other scoter species.