European Shag (Phalacrocorax aristotelis)
Is a type of cormorant, 68–78 cm long and with a 95–110 cm wingspan. It has a longish tail and yellow throat-patch. Adults have a small crest in the breeding season. According to that, this individual was probably not yet breeding-mode because if you look at the last picture of a breeding pair made in Sunburgh Head (another part of Shetlands) in those you can really notice the crest in their heads (is really funny, in fact).
Rocky shores of western and southern Europe, southwest Asia and north Africa. This one was in Unst, Shetland I.
The European Shag or Common Shag is a species of cormorant. It breeds around the rocky coasts of western and southern Europe, southwest Asia and north Africa, mainly wintering in its breeding range except for northernmost birds. In Britain this seabird is usually referred to as simply the Shag.