Like the cormorant, the shag mainly feeds on fish, but it fishes in deeper water (3) and prefers different prey species (2). It dives for fish from the surface of the water with a pronounced leap (1).
The nest is located on offshore islands, rocky stacks and cliff ledges (8). It is made of twigs and rotting seaweed, and is said to have an extremely pungent smell that increases in intensity as the decomposition of the seaweed continues (3). After hatching, the chicks stay in the nest for eight weeks (5).
Shags tend not to travel great distances, adults usually remain within 100 kilometres of the breeding area, but juveniles move up to 200 kilometres (2). Occasionally a phenomenon known as a 'wreck' occurs, when adverse weather conditions drift birds inland, where they become stranded in unusual habitats. This results in very high mortality for immature birds (2).