Breeding pairs: 27,000 pairs
Wintering birds: 110,000 birds
Adult shags in breeding plumage are all black with a dark green glossy sheen. They have crests on their heads and a thin black bill which curves downwards and a bright yellow gape.
During winter shags are duller and don’t have the crest on their heads. Their chins and throats are brown mottled with grey. Both adult male and female shags look similar.
Juveniles are brown with pales heads and underparts. They reach sexual maturity at 4 years.
Shags nest in colonies on cliffs. They build their nests in cracks and crevices or among rocks and boulders. The nest is made from sticks, seaweed and other plant material and lined with softer materials such as grass.
Shags lay 3 pale blue eggs which are incubated by both male and female for a month. The chicks are naked when they hatch and rely on their parents to keep them warm. They are fed by regurgitation and fledge 53 days after hatching but depend on their parents for another 28 days.
Shags eat mainly fish and occasionally crustaceans and molluscs. They usually feed alone away from the colony but will also chase fish shoals in large flocks.
Shags can be seen all year round on Scottish islands and the coasts of Wales and South West England.
The shag’s scientific name is from Latinized Ancient Greek meaning bald raven and the species name commemorates the Greek philosopher Aristotle