The Gannets inhabit the northern hemisphere, and are met with in all seas from 70° north latitude to the tropics; further southward their absence is supplied by other species. They are abundant in Iceland, and the Faroe Islands, the Orkneys, and the Hebrides; upon the coast of Norway they are less frequent, but plentiful on the American shores, both of the Pacific and Atlantic. In Great Britain Gannets breed in great numbers on the Bass Rock, Souliskerry, St. Kilda, Ailsa, and Skellig Islands. They betake themselves to the open sea during the winter, pursuing the herrings, pilchards, and other fishes, upon which they dart nearly vertically. It would seem as if these birds entertained a sort of affection for certain islands, or particular localities upon the coast. When they have an opportunity of doing so, they like to pass the night on dry land, generally preferring high precipitous cliffs that rise abruptly from the sea, and from which they can see the waves breaking perpetually before them. Their choice in this particular is somewhat fanciful, at all events they are always to be seen on certain rocks, and seem as constantly to avoid others apparently just as well suited to their purpose. The power of flight possessed by these birds is very great; they appear to swim only while they give themselves a little rest upon the water, and are never seen upon dry land except during the breeding season, or when, as has been said, they come on shore to sleep. When trying to stand upon their feet they are very helpless, and their walk is hardly more than a waddle. Neither is their power of swimming of much avail; they allow themselves to be blown along by the wind without any exertion of their own, and, indeed, never use their legs except when compelled to do so. When they employ their wings, however, they make up for these deficiencies; their flight is, perhaps, inferior to that of the Petrels, but it is exceedingly swift and strong. After a few rapid strokes of the wings, apparently to give it the necessary impulse, the Gannet glides through the air like an arrow, wheeling round and turning with the greatest ease, at one time sailing close to the surface of the sea, at another rising high into the air, and guiding its course by the simple sloping of its wings. Its voice consists of a succession of harsh croakings, while that of the young birds is a disagreeable screech. Whoever has visited the localities where these birds breed, will have little difficulty in understanding the beds of guano which of late years have been so profitably turned to account. They congregate upon the islands selected as their nesting-places by hundreds of thousands, and by millions, insomuch that, using the words in their literal sense, the air all around is filled with them; "their multitudes shut out the light of the sun, and their voices deafen any visitor." Towards the end of April they first make their appearance upon these islands, and leave them again about October.