the morsel obtained, or to float upon the waves while enjoying it; Shearwaters commonly dash down with considerable impetus, and disappear after their prey for the moment; while the Diving Petrels procure their nourishment at a much greater depth. When handled, and perhaps especially when taken from a nesting-hole, the birds bite severely, and eject a quantity of amber-coloured or greenish oil from the beak, followed as a rule by semi-digested food, the fluid possessing a strong smell of musk, which is also perceptible in the feathers and the eggs. The nest of the Albatros is usually a truncated cone or cylinder of mud, grass, leaves, and moss, with a slight {63}depression on the top, colonies being formed on cliffs, rocky slopes, or bare hill-tops above the limit of trees; the Giant Petrel makes a similar structure at no great elevation; Shearwaters and their nearest allies collect a mass of grass and rubbish in a burrow scraped in a bank, among boulders, or in holes and crevices of rocks, accommodating themselves to little stone huts, provided by the fishermen, in the Canary and Salvage Islands.[65] Fulmars scrape a cup-shaped hollow on ledges of precipices, adding little or no lining, while most of the remaining forms utilise small burrows, or crannies among the scattered stones which collect upon the shores or at the base of cliffs. A single lack-lustre white egg is deposited, frequently marked with a ring of rusty spots towards the larger end, especially in the case of the lesser species. Adult and young Shearwaters are eaten by the natives of the Canaries, the islands of Scotland, Ireland, and elsewhere, _Puffinus brevicauda_ being the "Mutton-bird" of Australia, and _P. anglorum_ being termed "Fachach" in the Hebrides and North Ireland. In the case of _Pelagodroma_, we have positive evidence that both sexes incubate;[66] and before the eggs are laid the parents are not uncommonly found together in the hole when such a site is chosen. Incubation lasts from twenty-five to sixty days.