When the vessels sent to the whale fishery have passed the Shetland Islands, and entered the northern seas, which are almost always very rough, the Petrels are seen flying about amidst the eddies of foam which are formed by the movement of the ship. They keep in attendance until something is thrown overboard, for they are extremely voracious, and especially fond of fat, particularly that of the whale. When the fishermen begin to cut up a whale, the Petrels flock together to the number of several thousands. They are not afraid to approach within reach, so that they may be taken or killed with a blow from a boat-hook. Their plumage is so close, that shot fired at them, except at close range, will not penetrate. Petrels walk on land with much difficulty. When they require rest in the open sea, with their heads placed under their wings, they sleep on the water, allowing themselves to be borne about at the mercy of the wind. The most remarkable species are--the Giant Petrel (_Procellaria gigantea_), commonly called the Bone-breaker, which inhabits the tract of ocean between Cape Horn and the Cape of Good Hope; the Chequered Petrel (_P. capensis_), commonly called the Chequered Pintado, which is a native of the southern seas; the Fulmar Petrel (_P. glacialis_), which inhabits the Arctic seas; the Stormy Petrel (_P. pelagica_), commonly called the Storm-bird, which frequents the seas of Europe, and after a hurricane appears on the northern coasts of France; the Forster or Blue Petrel (_P. Forsteri_ or _cærulea_), Fig. 112, commonly called the Blue Petrel, which inhabits the Antarctic seas. Under the name of Puffins those species of Petrels are included which have bills as long, and sometimes longer, than their heads, and their nostrils in two distinct tubes. Among these are the Grey Puffin (_Puffinus cinereus_), which is very common in the Mediterranean, and builds its nest in Corsica; the English Puffin (_Puffinus anglorum_), which inhabits the northern regions of our hemisphere; the Brown Puffin (_Procellaria æquinoctialis_), which inhabits the Southern Ocean, and is frequently met with at the Cape. [Illustration: Fig. 113.--The Common Albatross (_Diomedea exulans_, Linn.).]