The remaining species, often called "Boobies," have the whole lower jaw and throat bare. Of these _S. cyanops_, common in the South Pacific and ranging through the intertropical seas to the Bahamas in summer, is white with sooty-brown remiges, the wing-coverts and the lateral portion of the tail being partly of the same colour; the bill is yellow, the feet are reddish, and the naked parts bluish. _S. leucogaster_, extending from tropical and sub-tropical America over the Pacific, Indian, and Atlantic Oceans,[78] has the upper parts and chest brown, the remaining lower surface, and occasionally the head and neck, white; the bill is yellow, the feet are greenish or yellowish, the bare skin is tinged with red or yellow. _S. piscator_, also of the intertropical seas, resembles _S. bassana_, but has slate-grey wing-quills, purplish-grey bill, reddish feet and naked parts. _S. variegata_, of the shores of Chili and Peru, is dark grey-brown with white head, neck, and under parts, and white markings above. _S. abbotti_, of Assumption Island, north of Madagascar, is allied to _S. cyanops_. In this Family the sexes are alike, while the young are usually dusky with white streaks and spots; but those of _S. cyanops_ are white below, and those of _S. leucogaster_ and _S. piscator_ chiefly sooty-brown, with {75}grey head, neck, and under surface in the latter. It apparently requires six years to attain the full adult plumage. Gannets are oceanic birds, only frequenting the land in stormy weather; they traverse very great distances, and the northern species move southward in winter. The flight is easy and powerful, with alternate flapping and sailing motion, the head being carried in a line with the body and the feet drawn up. The food consists of surface-swimming fish, squids, and the like, while the young obtain their nutriment by thrusting their bills into those of the parents, though it is disgorged for them when newly hatched. The prey is chiefly captured by diving, the plunge being made with great velocity from a considerable height and the body being submerged for several seconds; on coming to the surface the bird generally remains quiescent for a short period before again taking to the air, but occasionally swims for a longer period. When diving the wings are kept open until the last moment, and are then quickly closed. Gannets find the same difficulty in rising from a level spot as do Tropic-birds, and are less prone to perch than many other sea-birds. The note is a hoarse reiterated sound or, less commonly, a plaintive cry, much noise being often made by the large colonies when breeding. The nest is a mass of sea-weed and grass, placed on a ledge of some high cliff, on the top of a stack, or even on a low tree; while the eggs–never more than two in number–are occasionally deposited on the bare sandy beach, and are greenish-blue, thickly coated with a white chalky substance, which soon becomes soiled. Incubation lasts about six weeks.