Brown Booby
Encyclopedia
The Brown Booby is a large seabird
of the booby
family, Sulidae. The adult brown booby reaches about 76 centimetres (29.9 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.
recognised are:
Natural National Park, Colombia. 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. Another confirmed reproduction site is Gorgona NNP proper, with its cays of Gorgonilla, Juanchincho and El Horno, with its 150 confirmed pairs of Brown Boobies (S. leucogaster), is the most important known reproduction site for the etesiaca subspecies in the world. 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.
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.
S. l. etesiaca in Gorgona NNP presents all the conditions supporting the center-satellite model. 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.
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
of the booby
Booby
A booby is a seabird in the genus Sula, part of the Sulidae family. Boobies are closely related to the gannets , which were formerly included in Sula.-Description:...
family, Sulidae. The adult brown booby reaches about 76 centimetres (29.9 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
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
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
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
or squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
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.
Subspecies
The 4 subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
recognised are:
- Sula leucogaster brewsteri Goss 1888
- Sula leucogaster etesiaca Thayer & Bangs 1905
- Sula leucogaster leucogaster (Boddaert) 1783
- Sula leucogaster plotus (Forster,JR) 1844
Sula leucogaster etesiaca
The etesiaca subspecies is an endemic inhabitant of the American tropical Pacific and was originally described using individuals captured in GorgonaGorgona, Colombia
Gorgona is a Colombian island in the Pacific Ocean situated about 50 km off the Colombian Pacific coast and part of the municipality of Guapi in the Department of Cauca. The island is about 9 km long and 2.5 km wide, with a maximum height of 338 m ; with an area of 10 square miles...
Natural National Park, Colombia. 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. Another confirmed reproduction site is Gorgona NNP proper, with its cays of Gorgonilla, Juanchincho and El Horno, with its 150 confirmed pairs of Brown Boobies (S. leucogaster), is the most important known reproduction site for the etesiaca subspecies in the world. 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.
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.
S. l. etesiaca in Gorgona NNP presents all the conditions supporting the center-satellite model. 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.
External links
- Brown Booby videos, photos & sounds on the Internet Bird Collection