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Brown Booby | Sula leucogaster
Bruine gent | Piquero pardo
The Brown Booby is the commonest booby on the Caribbean side of the guide area and the only one that regularly fishes close inshore there. It perches on buoys, piles and rocks, flies low over the water in lines and plunges at an angle into shallow water. On the Pacific side it is replaced by Cocos Booby, which was formerly treated as a subspecies of Brown Booby.
Voice
Silent at sea. At the colony the male gives a high, whistled schew, the female a low, hoarse quacking kwaak or honking honk.
Recording: JAYRSON ARAUJO DE OLIVEIRA — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
64–85 cm; females are larger than males. Head, neck, breast and upperparts are uniform dark chocolate brown, the belly and undertail coverts white, with a sharp, straight border on the breast. The underwing has a white centre with a broad dark margin. Bill and legs are yellow. In the male the bare skin around the eye and bill base is bluish, in the female yellow. Juveniles are brown with a pale brown, mottled belly that merges gradually into the breast, and a grey bill.
Confusion species
Cocos Booby Sula brewsteri, on the Pacific side, has a greyish-white head and neck and a greyish bill in the male; females and juveniles are hard to separate from Brown Booby, but the two species barely overlap in the guide area. The brown morph of Red-footed Booby Sula sula is uniformly brown below, without a sharply defined white belly, and has red legs, or greyish-yellow ones in juveniles. Juvenile Masked Boobies Sula dactylatra are larger and have a white collar separating the brown hood from the mantle. Juvenile Brown Pelicans Pelecanus occidentalis are much larger, with a long, flat bill.
Habitat
Coastal waters, bays, harbours and open sea over the continental shelf. It often plunges at a shallow angle from low height and also catches flying fish above the water. It rests on buoys, boats, rocks and piles. It breeds in colonies on the ground, on rocky islets, cays and cliffs, with a nest of shell fragments and plant material; of the two eggs usually only one chick is raised.
Where the bird is most at home, classified by the vegetation units of Mexico and Central America.
Range and movements
Year-round along the Gulf and Caribbean coasts of the guide area, from Tamaulipas and Veracruz across the Campeche Bank and the Yucatán Peninsula to Belize, Honduras, Nicaragua, Costa Rica and Panama. Colonies include Arrecife Alacranes and Cayo Arcas off Yucatán and Campeche and islets off Belize and Honduras. Very rare on the Pacific side. Birds in the guide area belong to the Atlantic nominate form S. l. leucogaster. Outside the guide area in the tropical Atlantic Ocean, the Caribbean and the tropical Indian and western Pacific Oceans.
- Resident
- Summer visitor (c. Apr–Sep)
- Winter visitor (c. Oct–Mar)
- Passage (Mar–Apr, Oct–Nov)
- dark = core range, pale = thinly spread
How and when to look
Buoys and piles in harbours along the Caribbean coast, such as at Cancún, Cozumel and the cayes of Belize, often offer good chances. From ferries and on boat trips, hunting birds can be seen alongside the vessel. Adults are recognised by the sharp border between the brown breast and the white belly.
Conservation status
Not threatened. Colonies are threatened by introduced rats and cats, disturbance, the taking of eggs and chicks and entanglement in fishing gear; plastic is often found in nests.
Scientific name
Sula leucogaster | (Boddaert, 1783)
Boddaert described the species in 1783 as Pelecanus Leucogaster; because it was later moved to another genus, the author and year stand in brackets. The genus Sula was introduced in 1760 by Brisson. Sula goes back to súla, the Old Norse and Icelandic word for the gannet; the name passed to the boobies. leucogaster is Greek, from leukos 'white' and gastēr 'belly', after the white underparts. The specimen the first description was based on came from Cayenne, French Guiana.