Northern Ireland's Priority Species

Aythya marila – scaup

Aythya marila

Aythya marila (L.)
Family: Anatidae

The scaup is a diving duck and is closely related to pochard and tufted duck. They are equally at home on large lakes and sea loughs, where they can form into large ‘rafts’ or groups of birds.

In brief

  • Scaup are diving ducks, which feed on shellfish;
  • They are winter visitors, mostly to Lough Neagh, as well as coastal sites such as Belfast and Carlingford Loughs;
  • Breeding has occurred at Lough Neagh;
  • The scaup is a SOCC mainly because it occurs in Northern Ireland in numbers of international importance;
  • Scaup can be vulnerable to deteriorating water quality.

Species description
Scaup are the biggest of our three Aythya diving duck species, being bulkier and marginally longer than pochard and tufted duck. Males appear black and white at a distance. They have black heads with a green gloss, blackish breasts and rear end, with contrasting pale grey back and white sides. Females are mainly brown, paler on the back and flanks, and sport a white patch on the face around the base of the bill. Young males are more blotchy than adults, especially on the flanks and back. In flight, both sexes show a broad white wing-bar, and a white belly. Scaup frequently dive for their prey, but feed more at night, spending the day resting on the surface in flocks.

Life cycle
Scaup arrive in September from their breeding grounds in Iceland, although some immigrants may also come from north eastern Europe. Our wintering birds return to their northern wintering grounds in April, where they nest in thick vegetation close to water. A few scaup do remain in Northern Ireland each summer and breeding has been recorded recently at Lough Neagh, when young ducklings were seen. Scaup feed mainly on small molluscs, especially when at marine or coastal sites, but on Lough Neagh their favoured food are the larvae of Chironomids — the famous Lough Neagh non-biting midges.

Similar species
Inexperienced observers may mistake scaup for either tufted duck or pochard. Male scaup are bigger than tufted duck, show a pale grey back and have no head tuft. They can be distinguished from pochard by the dark green-black head, pale back and white sides. Females show white feathering around the base of the bill, as do some female tufted ducks. However, the scaup always has much more extensive white feathering and generally look greyer on the back and sides. Female pochard are greyer still, and show a more sloping forehead than the round-headed scaup.

How to see this species
Scaup tend to feed at night, but are easy to see during the day loafing about in large flocks. The north end of Lough Neagh is a favoured locality, especially off Ballyronan marina in the north-west. Belfast Lough is also a regular haunt, and the flock is usually close in to the port at Dargan Bay. The scaup flock at Carlingford Lough can be more mobile, but is often seen from the shoreline between Warrenpoint and Rostrevor.

Current status
Between 3,000-5,000 scaup winter in Northern Ireland, with the vast majority in Lough Neagh which is internationally important for this species. Scaup have bred at Lough Neagh, but this may not be an annual occurrence. While the other species of diving duck on Lough Neagh have declined drastically in recent years, scaup numbers have been more stable, and 2004/05 was one of the best years in recent times with over 5,000 counted. Other important sites are Carlingford and Belfast Loughs, with flocks of several hundred being regularly counted.

The scaup is a quarry species, but is specially protected during the shooting close season from to 1 February to 31 August under the Wildlife (NI) Order 1985.

Why is this species a priority in Northern Ireland?

  • The scaup is a SOCC because it is an Amber-listed species in both Irish and UK Birds of Conservation Concern lists. It is included for several reasons:
    • More than half of the UK wintering population is at ten or fewer sites
    • It is a rare breeding bird in both UK and Ireland
    • The scaup is a Species of European Conservation Concern due to significant declines in its NW European wintering population.

Threats/Causes of decline
Scaup are vulnerable on their European breeding grounds to shooting and habitat loss. Deterioration of water quality could affect their food supplies at Lough Neagh or other sites.

Conservation of this species

Current action

  • The scaup’s principal site — Lough Neagh — has been designated an Area of Special Scientific Interest
  • Key sites are surveyed each winter by a combination of conservation bodies and volunteer counters as part of the nationally co-ordinated Wetland Bird Survey (WeBS)
  • The Eutrophic standing waters Habitat Action Plan provides a range of actions relevant to the conservation of scaup habitat.

Proposed objectives/actions

  • Scaup numbers at the most important sites will continue to be monitored through WeBS surveys, and appropriate conservation action undertaken, if required.

What you can do

  • Volunteer as a Wetland Bird Survey counter by contacting EHS or RSPB
  • Report incidents of illegal shooting to PSNI or EHS
  • Avoid disturbance to wintering duck flocks.

Further information

RSPB Fact Sheet

Wetland Bird Survey

EHS report on Lough Neagh diving ducks

Eutrophic standing waters Habitat Action Plan

Designated areas

Crowe, O. (2005). Ireland’s Wetlands and their Waterbirds: Status and Distribution. Birdwatch Ireland.

Kear, J. (2005). Ducks, geese and swans. Oxford University Press.

Text written by:
Allen & Mellon Environmental Ltd.