Quick Answers
Scaup and tufted duck are two species of diving ducks that are closely related and can be difficult to distinguish. Here are some key differences:
- Scaup have a rounder head shape compared to the peaked head shape of tufted ducks.
- Male scaup have green heads whereas male tufted ducks have purple heads.
- Female scaup are brown with a white patch at the base of the bill. Female tufted ducks have a darker brown body and lack the white facial patch.
- Scaup tend to dive deeper than tufted ducks when feeding.
- Tufted ducks are found across Europe and Asia while scaup are primarily North American, with some Eurasian populations.
Identification
Scaup and tufted duck belong to the genus Aythya which includes several similar looking diving duck species. Careful observation is needed to distinguish between scaup and tufted duck when they occur in the same location.
There are two scaup species – the greater scaup (Aythya marila) and the lesser scaup (A. affinis). They are very difficult to tell apart. For our purposes, the identification points can apply to both scaup species when comparing them to tufted ducks.
Size and Shape
In terms of size, scaup measure 16-20 inches (40-51 cm) in length with a wingspan around 30 inches (76 cm). They are slightly larger than tufted ducks which have a length of 15-17 inches (38-43 cm) and wingspan of 26-29 inches (66-74 cm).
The most noticeable difference between the two is their head shape. Scaup have a more rounded head profile while tufted ducks have a peaked head shape with a shaggy crest at the back.
Plumage
Adult male scaup have a greenish head and neck, white sides, black chest, gray back and a black rump. Their belly is white with flanks that are vermiculated gray and white giving a scaly appearance.
Male tufted ducks also have a black chest and back but their head and neck is a deep iridescent purple. Unlike the green on scaup, the purple can appear different shades depending on the lighting. Tufted ducks lack the gray vermiculated pattern on the flanks.
Females of the two species show more pronounced differences. Female scaup are entirely brown except for a large white patch at the base of the bill which extends behind the eye. Their eyes are yellow.
Female tufted ducks are also brown but have a darker brown body than the female scaup. They lack the white facial patch and instead have a yellowish face and yellow eyes with brown irises.
Behavior and Habitat
Scaup and tufted ducks share similar habitat preferences during the breeding season. They nest near ponds, lakes, marshes and other wetlands across their respective ranges.
During the rest of the year, they inhabit coastal marine areas, estuaries, bays and lakes. Large rafts of scaup and tufted ducks can mix together in migration and wintering grounds.
While feeding, scaup typically dive deeper than tufted ducks – up to 20 meters deep compared to the 5 meter average depth of tufted ducks. However, tufted ducks are more aggressive feeders and will readily displace other diving ducks from prime feeding areas.
In terms of breeding, scaup nest on the ground near water while tufted ducks use nest boxes and other elevated cavities for nesting when available.
Range and Population Status
The continental ranges of scaup and tufted duck generally do not overlap which helps reduce confusion between these lookalike species in most locations.
Greater and lesser scaup are primarily North American species that breed across Alaska and Canada. Some breeding also occurs at inland locations in the northernmost United States. Eurasian populations of scaup occur in Iceland, Scandinavia and Russia.
Outside of the breeding season, scaup migrate down the Pacific and Atlantic coasts of North America. They winter as far south as Mexico and Florida.
In contrast, tufted ducks are widespread across Europe and Asia. They breed across northern Eurasia down to southern Europe and northern China. Small numbers reach the United Kingdom and Scandinavia. In winter, they migrate down to the Mediterranean, Black Sea, northern Africa and southern Asia.
Introduced populations of tufted ducks now exist in parts of North America where they overlap with scaup on migration and wintering grounds. However, tufted ducks are still scarce in North America which helps avoid confusion there.
Both scaup species have experienced population declines in recent decades with numbers down by close to 60% since the 1970s according to monitoring surveys. However, tufted ducks remain abundant across Eurasia with a large and increasing population trend.
Conclusion
While similar in appearance, scaup and tufted ducks can be reliably distinguished by their head shape, coloration differences such as the white facial patch on female scaup, along with their predominant ranges and habitat use. Being aware of the subtle differences allows birders to properly identify these diving ducks even when they occur in the same location outside of their core ranges.
