Brown Booby

The Brown Booby is the most widely distributed booby in the world, found across tropical and subtropical oceans on nearly every continent's warm coastlines. It shows a bold, sharply demarcated plumage pattern: rich chocolate-brown covering the head, back, and breast, cutting cleanly across the chest to a crisp white belly and underwing coverts. The bill and facial skin are yellow to greenish-yellow, brighter in males, and the legs are a similar dull yellow.

As a familiar sight resting on buoys, boats, and rocky islets throughout the tropics, the Brown Booby is often the booby species most likely to be seen by casual observers along tropical coastlines.

Key field marks

• Sharp two-tone pattern: dark brown chest and upperparts, white belly
• White underwing coverts contrasting with dark flight feathers
• Yellow to greenish-yellow bill and facial skin
• Yellowish legs and feet (not red or blue)

Similar species

• Red-footed Booby is smaller with red feet and more variable plumage, including all-white and brown morphs.
• Masked and Nazca Boobies are white-bodied with black masks, quite different from the all-brown chest of Brown Booby.
• Juveniles are more uniformly grey-brown overall, lacking the crisp adult contrast, and take a couple of years to mature.

Brown Boobies breed on rocky islets, cliffs, and sandy cays throughout the tropical and subtropical Atlantic, Pacific, and Indian Oceans, nesting close to warm coastal waters. They are less pelagic than some relatives, often staying near coastlines, reefs, and continental shelves rather than ranging far into open ocean.

The species is essentially non-migratory, though individuals, especially young birds, can wander considerable distances and are increasingly recorded well outside their core tropical range, including occasional vagrants along temperate coastlines.

Behavior

Brown Boobies are agile plunge-divers, often hunting cooperatively or alongside other seabirds and predatory fish that push baitfish to the surface; they also frequently rest on buoys, ships, and rocky perches.

Voice

At colonies, they give harsh honking and quacking calls, with males typically higher-pitched and thinner than the deeper calls of females.

Feeding

Small fish such as flying fish, herring, and anchovies, along with squid, are caught in shallow plunge dives close to shore or over reefs.

Nesting and breeding

Nests are simple ground scrapes on rocky or sandy substrate, sometimes lined with vegetation; typically two eggs are laid, though usually only one chick survives to fledging due to sibling competition.