Scaup Diet and Size: Feeding Habits, Predators, and Measurements

Scaup also known as Greater Scaup in North America are diving ducks that are winter visitors to UK shores. In the US they are also known as “Bluebills” due to the colour of their bills.

The males or “drakes” are larger than the females and have a more rounded head. Both males and females are easily recognisable due to their blue bills and bright yellow eyes.

In this article we’ll be looking into the diet and size of these fascinating winter visitors as well as much more besides.

The Dietary Habits Of The Scaup

Like many waterbirds, the diet of the Scaup revolves around their aquatic environments.

What Does A Scaup Eat?

Scaup mainly eat aquatic invertebrates and plant material. Their food sources include molluscs (like clams and snails), crustaceans, insects and small fish. They also eat the leaves, stems and seeds of aquatic plants like pondweed and wild celery.

Scaup can dive up to 23 feet (7 metres) below the surface of the water to retrieve invertebrates from the muddy beds of lakes or oceans.

What To Feed A Baby Scaup? 

Although the chicks are precocial and typically feed themselves around 24 hours after hatching. The female will feed the newly hatched chicks a diet of small aquatic invertebrates like insects and small crustaceans.

These foods provide the high protein content needed by the chicks for their rapid growth. The ducklings are then led to the water by their mother at around the age of 24 hours and shown how to find this food for themselves.

Breeding Habits Of Scaups

Male Scaup will initiate courtship during the winter months and continues into early spring. He will stretch his neck upwards and then throw his head back onto his back whilst kicking water with his feet at the same time.

This action is often accompanied by a whistling call. Males will also perform flights chasing the female over the water whilst making loud calls.

The pairs are often formed before they arrive at their breeding grounds and they migrate together. The female then constructs the nest which is a scrape in the ground lined with soft plant material and feathers.

The female incubates the eggs on her own for around 23 to 28 days. The male takes no part in the incubation but is close by. The precocial chicks follow their mother to the water around 24 hours after hatching and learn to fend for themselves.

Do Scaups Mate For Life?

Like many duck species, Scaup are only monogamous for one breeding season. These pairings last for around 3 weeks into the incubation period when the male leaves the area completely and the raising of the chicks is left to the female.

The following breeding season, both ducks will form another season-long monogamous pairing.

The Size & Weight Of Scaups

When seen from a distance, Scaup looks very similar to Tufted Ducks. However, Scaup are heavier and slightly larger.

How Much Does A Scaup Weigh?

The average weight of an adult Scaup is around 0.8 to 1.3 kg. Females are typically smaller than males and will therefore weigh less.

Having said that, a female’s weight will increase during the egg laying period as she produces a clutch of eggs that weigh an average of 67 grams per egg.

How Big Is A Scaup?

The average length of an adult male Scaup is around 42 to 51 cm with a wingspan of around 67 to 78 cm. Again the female is typically the smaller of the pair.

Are Scaups Under Threat?

Scaups are facing a number of threats that have led to concerns about their long-term survival. Although they are considered a species of least concern by the IUCN, there are some regional populations that are experiencing more significant declines.

In the UK, due to their rare status as a breeding bird, they have Red status on the British Birds of Conservation Concern list.

The reasons for the decline in the Scaup population include habitat loss due to wetland degradation and climate change, pollution including agricultural run-off, industrial waste and spillage, over hunting and a loss of readily available food sources.

What Eats A Scaup?

Scaup face predation from various creatures especially during the most vulnerable phases of their lives. These phases include moulting when they lose their flight feathers, eggs, egg laying and ducklings.

Mammals like foxes, raccoons and skunks are known to prey on Scaup eggs and ducklings and can become particularly aggressive around nests.

Other predators include Gulls, Crows and Ravens as well as birds of prey like Hawks, Peregrine Falcons, Eagles and Owls. Ducklings are often predated by large fish like pike.

One of the main predators that Scaup have to deal with are human hunters. Scaup are legally hunted in many areas and over hunting can seriously impact population numbers unless properly managed.

Where Can I See Scaups In The UK?

Scaup can be seen in the UK during the winter months where large numbers arrive from breeding grounds in Northern Europe and Russia. They are typically found in coastal and inland water bodies.

Some of the best places to observe Scaup in the UK include;

Scotland

• Firth of Clyde
• Loch Ryan

North-West England

• Morecambe bay

Northern Ireland

• Lough Neagh
• Strangford Lough

Northern England

• RSPB Leighton Moss
• Rutland Water

Eastern England

• The Wash
• Norfolk Broads
• Abberton Reservoir (Essex)

Southern England

• Chew Valley Lake (Somerset)

The best time to see Scaup is from October to March with numbers peaking from November to February. They tend to gather in flocks often alongside Tufted Ducks.

They are more common in coastal areas but can also be spotted on large freshwater lakes and reservoirs during winter months.

SEE ALSO: Whooper Swan Diet and Size: Feeding Habits, Predators, and Measurements

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