| Brown Booby | |
|---|---|
| Brown Booby on Oahu, Hawaii | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Pelecaniformes |
| Family: | Sulidae |
| Genus: | Sula |
| Species: | S. leucogaster |
| Binomial name | |
| Sula leucogaster (Boddaert, 1783) |
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The Brown Booby (Sula leucogaster) is a large seabird of the booby family, Sulidae. The adult brown booby reaches about 76 centimetres (30 in) in length. Its head and upper body are covered in dark brown, with the remainder being a contrasting white. The juvenile form is gray-brown with darkening on the head, wings and tail. While these birds are typically silent, bird watchers have reported occasional sounds similar to grunting or quacking.
Their heads and backs are black, and their bellies are white. Their beaks are quite sharp and contain many jagged edges. They have short wings and long, tapered tails.
This species breeds on islands and coasts in the pantropical areas of the Atlantic and Pacific oceans. They frequent the breeding grounds of the islands in the Gulf of Mexico and the Caribbean Sea. This bird nests in large colonies, laying two chalky blue eggs on the ground in a mound of broken shells and vegetation. It winters at sea over a wider area.
Brown Booby pairs may remain together over several seasons. They perform elaborate greeting rituals.
Brown Boobies are spectacular divers, plunging into the ocean at high speed. They mainly eat small fish or squid which gather in groups near the surface and may catch leaping fish while skimming the surface. Although they are powerful and agile fliers, they are particularly clumsy in takeoffs and landings; they use strong winds and high perches to assist their takeoffs.
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The 4 subspecies recognised are:
The etesiaca subspecies is an endemic inhabitant of the American tropical Pacific and was originally described using individuals captured in Gorgona Natural National Park, Colombia.[1] In the eastern tropical Pacific S. leucogaster is known to breed in the rocks of Octavia, Los Vidales and Centelinas de Jurubidá, in Chocó, with a low number of individuals.[2] Another confirmed reproduction site is Gorgona NNP proper, with its cays of Gorgonilla, Juanchincho and El Horno,[1][3] with its 150 confirmed pairs of Brown Boobies (S. leucogaster), is the most important known reproduction site for the etesiaca subspecies in the world.[2][3] Nesting sites are located in the sectors of Gorgonilla islet, which hosts nine nesting sites, Juanchincho which hosts two, and El Horno with another two nesting sites. The two cays of Juanchincho are in the NW coast; in this zone Pelicans, Frigate birds and Blue-footed Boobies are less frequent and no nests of these species have been found.[3][4]
In Gorgona Island, Brown Boobies breed asynchronously; in censuses carried out every fifteen days, at the same moment nesting pairs, nests with eggs, nests with chicks and nests with fledged chicks were recorded. Two reproductive peaks can be observed, with the period of higher activity between October and January. From March until July the reproduction rate was lower, reaching less than 27% of the preceding reproductive peak.[3]
S. l. etesiaca in Gorgona NNP presents all the conditions supporting the center-satellite model.[3] In this species occurrence, a central male with a higher Physical Quality Index (PQI) lives surrounded by satellite males with lower PQIs, following the commodity selection hypothesis.[5]