Highly sought after species like lanceolated and Pallas's grasshopper warblers, yellow-breasted bunting, pechora pipit and great snipe are just a few examples of what bird watchers expect to see. The winter months are also an exciting time for the bird watcher. Many high Arctic breeding birds choose to spend the winter in Shetland. The large lochs like Loch of Spiggie hold large numbers of whooper swans, goldeneye and wigeon while the sheltered voes hold great northern divers, long-tailed ducks and Slavonian grebes. First class rarities like gyrfalcons, ivory gulls and white-billed divers also put in appearances.
Sea mammals are well represented in Shetland.
Numerous, highly attractive and sometimes comical though they both are, identifying them from each other can prove very difficult for those with untrained eyes. Hugh Harrop One of the best-distinguished features is the shape of the head. The grey seal has a high muzzle giving it a 'Roman nose' effect, especially in males, while the common seal has a low dog-like muzzle with a relatively rounded head and distinct forehead, producing a much more appealing and expressive appearance. If you see either species close enough, then you will be able to see the common seals nostrils forming a V shape while those of the grey seal are almost parallel. The commonest species by far is the harbour porpoise, which tends to favour sheltered voes or channels between islands.