When the season for incubation arrives, the birds assemble in vast numbers, and for some days appear to be deliberating upon the proper course to be pursued. At length they proceed to action. A level piece of ground is selected, of suitable extent, usually comprising three or four acres, and situated as near the sea as possible, being still beyond its reach. The spot is chosen with reference to its evenness of surface, and that is preferred which is the least encumbered with stones. This matter being arranged, the birds proceed, with one accord, and actuated apparently by one mind, to trace out, with mathematical accuracy, either a square or other parallelogram, as may best suit the nature of the ground, and of just sufficient size to accommodate easily all the birds assembled, and no more--in this particular seeming determined upon preventing the access of future stragglers who have not participated in the labour of the encampment. One side of the place thus marked out runs parallel with the water's edge, and is left open for ingress or egress. Having defined the limits of the rookery, the colony now begin to clear it of every species of rubbish, picking up stone by stone, and carrying them outside of the lines, and close by them, so as to form a wall on the three inland sides. Just within this wall a perfectly level and smooth walk is formed, from six to eight feet wide, and extending around the encampment--thus serving the purpose of a general promenade. The next process is to partition out the whole area into small squares exactly equal in size. This is done by forming narrow paths, very smooth, and crossing each other at right angles throughout the entire extent of the rookery. At each intersection of these paths the nest of an albatross is constructed, and a penguin's nest in the centre of each square--thus every penguin is surrounded by four albatrosses, and each albatross by a like number of penguins. The penguin's nest consists of a hole in the earth, very shallow, being only just of sufficient depth to keep her single egg from rolling. The albatross is somewhat less simple in her arrangements, erecting a hillock about a foot high and two in diameter. This is made of earth, seaweed, and shells. On its summit she builds her nest. The birds take especial care never to leave their nests unoccupied for an instant during the period of incubation, or, indeed, until the young progeny are sufficiently strong to take care of themselves. While the male is absent at sea in search of food, the female remains on duty, and it is only upon the return of her partner that she ventures abroad. The eggs are never left uncovered at all--while one bird leaves the nest, the other nestling in by its side. This precaution is rendered necessary by the thievish propensities prevalent in the rookery, the inhabitants making no scruple to purloin each other's eggs at every good opportunity.