Cormorant and Shag

The shag and the cormorant are closely related and both can be seen on the Pembrokeshire islands. Whilst the shag is exclusively a coastal bird, the cormorant will often also be found on inland waterways, lakes and estuaries. Both birds are deep-diving, benthic feeders and shags have been recorded at depths of 50m. They use their feet to propel themselves underwater and, unlike most seabirds, they have the curious adaptation of only semi-waterproof feathers to help them reach these depths.

Their feathers absorb water, which makes them heavy and allows them to reach great depths with relative ease. The downside of this is, if their feathers become too waterlogged, they risk drowning, so every couple of dives they have to stand out on the rocks and hang their wings out to dry. Whilst from a distance these two species can be almost indistinguishable, close up they have a number of distinctive differences.