The Glacial Petrel (_Procellaria gelida_) does not seem to approach the pole so near as the fulmar. He appears but seldom in Iceland, but breeds frequently in Newfoundland. The same is the case with the Shearwater (_P. puffinus_), which breeds in great numbers on the Feroë islands, and in Orcadia. The tropical petrels are the least known. They do not appear to gather troopwise, and but seldom follow ships. Towards 45° S. lat. the first Pintados (_P. capensis_) make their appearance, and are more rarely seen after having passed 60° S. lat. The Giant Petrel (_P. gigantea_), extends its flight as far as the ice-banks of the south, where the Antarctic and the Snowy (_P. antarctica et nivea_) Petrels first appear, birds which never leave those dreary seas, and are often seen in vast flocks floating upon the drift ice. Thus nature has set bounds to petrels, as to all other creatures that swim or fly in and over the ocean, and has divided the wide deserts of the sea among their different species. Who can tell us the mysterious laws which assign to each of them its limits? Who can show us the invisible barriers they are not allowed to pass?
The Stormy Petrel (_P. pelagica_) seems to belong to every sea. It is about the size of a swallow, and in its general appearance and flight is not unlike that bird. Although the smallest web-footed bird known, it braves the utmost fury of the tempest, often skimming with incredible velocity the trough of the waves, and sometimes gliding rapidly over their snowy crests. Like all of its kind, it lives almost constantly at sea, and seeks during the breeding season some lonely rock, where it deposits in some fissure or crevice its solitary egg.
The mode of life of the petrels corresponds but little with their external beauty; they are in fact the crows of the ocean, and live upon the dead animal substances floating on its surface. Wherever the carcase of a whale, borne along by the current, covers the sea with a long stripe of putrid oil, they are seen feasting in the polluted waters. All petrels have the remarkable faculty of spouting oil of a very offensive smell, from their nostrils when alarmed, and this apparently as a means of defence.