The guillemot (Uria aalge), known as the aak in Orkney, has a dark brown head, neck and upperparts.  It has a distinctive white line across closed wings.  The bill is black and tapering and legs are dark blue. The guillemot’s eggs are pear shaped to prevent them rolling off cliff ledges.  There are around 181,000 adults in Orkney. There are plenty of places to see them but Noup Head in Westray is always good in the summer, as is Marwick Head on the mainland.  It gathers fish (sandeels) crossways in its beak, with the heads all pointing to the left or all to the right.

The black guillemot (Cepphus grille) is called the tystie in Orkney.  It is smaller than the common guillemot, and can be seen on boulder beaches and low cliffs around the islands.  It has smart black and white plumage and red feet and is an auk - related to the puffin and razorbill.  It stays local all year round but spends winters at sea within a few miles or so of breeding grounds.  The sexes are similar with a summer plumage of jet black and a large oval white patch on upper wing and under wing.  In winter the tystie is whiter with a speckled grey and white back.  They feed on butterfish.

They can be seen around Orkney’s cliffs, especially Marwick Head, Hobbister and Papa Westray’s north and east shores. The highest number of black guillemot in Britain is in Orkney and Shetland with a population in Orkney of around 5,500 adults.  In England there is only one colony in Cumbria of a few pairs and 14 pairs in Wales. They are common in the Arctic and north Atlantic.