The shag is a smaller relative of the cormorant, more strictly coastal and marine than cormorant, with a distinctive green iridescent plumage and recurved crest in the breeding season.
Shag welfare is threatened by oilspills, HPAI, and sandeel decline. The wreck of hundreds of shags from poisoning (Paralytic shellfish poisoning from red tides) has occurred in some years. Climate change affecting coastal fish stocks is a longer-term concern.