Marine Wildlife Encyclopedia
Brown Booby Sula leucogaster
The brown booby is a superb diver. It is the most widespread booby and has distinct color variations. Most brown boobies are brown all over, apart from a white underside. However, birds from the eastern Pacific have white heads and their bills are gray rather than the typical bright yellow. They all live in the same way, diving for fish and squid from heights of up to 100 ft (30 m). Brown boobies also skim low over the surface, looking for flying fish, which they catch in midair. They often fly in front of ships, watching for fish caught up in the bow-waves, and they like to fish close to land, roosting on buoys or coastal trees. Despite their agility in the air, they are clumsy at takeoff and landing.
Plunge-diving Brown Boobies
Gannets and boobies all show adaptations for a plunge-diving lifestyle: forward-facing eyes, streamlined heads and bills; and nostrils with no external openings. Their wings fold back along the body just before the moment of impact, and the force is absorbed by air sacs under their skin.