The shag is medium-to-large dark-feathered, reptilian-looking bird. It is a widespread resident breeding species in coastal regions throughout Scotland. Although similar to the cormorant, shags are smaller, slimmer, with a steep forehead and narrower bill. In breeding plumage, adult shags displays a very distinctive crest on the forehead. They have a bright yellow gape and a green sheen to their feathers.

Behaviour

Shags tend to fly very low over the sea and often feed in dense flocks. When diving for fish, the shag will jump clear of the water before diving down in pursuit of fish. Like cormorants, the shag is frequently seen perched on rocks or piers with outstretched wings. This posture is typically used for drying the wings after diving, given that their plumage is only partly waterproof.

Shags are monogamous and social, breeding in large, dense colonies and foraging either alone or in large flocks during the day. The nests are untidy heaps of rotting seaweed or twigs cemented together by the bird’s own guano. The nesting season is long, beginning in late February, with some nests not starting until May or even later. Fledging may occur at any time from early June to late August, but can be as late as mid-October.

Size

• Length: 65-80cm
• Wingspan 90-105cm
• Weight: 5-2.25kg
• Average lifespan: 12-15 years

Status

Classified in the UK as Red under the Birds of Conservation Concern 4: the Red List for Birds (2015). Protected by The Wildlife and Countryside Act 1981.

Distribution

Common breeding species found on most of Scotland’s coasts with the largest colonies found in the north and west and the Firth of Forth. Notable gaps in distribution are found in parts of the Moray and Solway Firth and it is rare to find Shags inland. The distribution changes very little between summer and winter, though numbers may be reduced by the southerly movement of some, usually immature birds, into England, or easterly movement from the Shetland Isles to Norway.

When to see

Shags can be readily seen between March-October during the breeding season. They are present, but in reduced numbers, between December-February, especially in the Firth of Forth, around Caithness and the Northern Isles.

Facts

• The shag is one of the deepest divers among the cormorant family. European shags have been shown to dive to at least 45 metres. They are predominantly benthic feeders, e., they find their prey on the sea bottom.
• The UK has approximately 10% of the world’s breeding population of Shag.
• Three decades of data from the Isle of May, off Scotland’s east coast found that the proportion of sandeels, the shag’s usual fayre, declined by 48% between 1985 and 2014. Over the same period, the number of other fish prey in the Shag’s diet increased, from an average of just one species per year in 1985 to eleven in 2014. The increase in diet diversity was linked to warming trends in sea surface temperature, an indicator of climate change and the shag’s adaption to it.