Should a man approach the nest, the old birds at once fly into the air screaming furiously, and sometimes boldly attack the rash intruder on their privacy by dealing violent blows about his head and face. Sometimes, according to Graba, bird-catchers hold knives above their caps, upon which the birds occasionally impale themselves as they swoop violently down and endeavour to wound the enemy's head. Both parents assist in the work of incubation, and hatch the eggs in about four weeks. The young are nimble, gallant little fellows, and leave the nest almost immediately after quitting the shell. A writer in the Records of the Wernerian Society informs us that on alarm of danger they secrete themselves with great art behind stones, or in holes, and if captured make a most amusing show of defence. When first hatched, the fledglings are warmly clad in greyish brown down, and are reared upon small mollusca, worms, eggs, and similar delicacies, disgorged from the parents' crop; at a later period they are supplied with half-digested fish or flesh, or sometimes with young birds. When able to provide for themselves, they are said to eat berries of different kinds. By the end of August they have attained their full growth, and in September are able to fly out to sea. The Common Skua is easily tamed, and in some places, says Mr. Dunn, is a great favourite with the fishermen, frequently accompanying their boats to the fishing-ground; this the fishermen consider a lucky omen, and in return for its attendance they give it the refuse of the fish which are caught, or supply it with any useless garbage from their nets. BUFFON'S OR THE PARASITE SKUA.