Brown booby

The brown booby (Sula leucogaster) is a large seabird in the booby and gannet family Sulidae, of which it is one of the most common and widespread species.<ref name="ph">Template:Cite book</ref> It has a pantropical range, which overlaps with that of other booby species. The gregarious brown booby commutes and forages at low height over inshore waters. Flocks plunge-dive to take small fish, especially when these are driven near the surface by their predators. They nest only on the ground, and roost on solid objects rather than the water surface.<ref name="ph"/>

Taxonomy

The brown booby was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in his Histoire Naturelle des Oiseaux in 1781.<ref>Template:Cite book</ref> The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text.<ref>Template:Cite book</ref> Buffon did not include a scientific name with his description but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Pelecanus leucogaster in his catalogue of the Planches Enluminées.<ref>Template:Cite book</ref> The type locality is Cayenne in French Guiana.<ref>Template:Cite book</ref> The current genus Sula was introduced by the French zoologist Mathurin Jacques Brisson in 1760.<ref>Template:Cite book</ref> The word Sula is Norwegian for a gannet; the specific leucogaster is from Ancient Greek leuko for "white" and gastēr for "belly".<ref>Template:Cite book</ref>

There are two recognised subspecies:<ref name="ioc">Template:Cite web</ref>

• S. l. leucogaster (Boddaert, 1783) – Caribbean and Atlantic Islands
• S. l. plotus (Forster, JR, 1844) – Red Sea through the Indian Ocean to the west and central Pacific<ref name="Redman Stevenson Fanshawe 2016">Template:Cite book</ref>

In 2024, two other formerly accepted subspecies, S. l. brewsteri and S. l. etesiaca, were split out as a separate species Cocos booby Sula brewsteri by the American Ornithological Society, Clements Checklist, and the IOC World Bird List.<ref name="ioc"/>

• male S. l. plotus, French Frigate Shoals
  male S. l. plotus, French Frigate Shoals
• female S. l. plotus, Green Island, Queensland
  female S. l. plotus, Green Island, Queensland
• male S. l. plotus, Queensland
  male S. l. plotus, Queensland
• female S. l. plotus, Queensland
  female S. l. plotus, Queensland

Description

The booby's head and upper body (back) is covered in dark brown to blackish plumage, with the remainder (belly) being a contrasting white. The bare-part colours vary geographically, but not seasonally.<ref name="ph" /> The species also displays sexual dimorphism of the bare part colours, the males having a blue orbital ring, as opposed to the yellow orbital ring of the female.

Female boobies reach about Template:Convert in length; their wingspans measure up to Template:Convert, and they can weigh up to Template:Convert. Male boobies reach about Template:Convert in length; their wingspans measure up to Template:Convert, and they can weigh up to Template:Convert.<ref name="ospina-alvarez">Template:Cite journal</ref>Template:Clarify

Unlike other species of sulid, the juvenile plumage already resembles that of the adult.<ref name="ph" /> They are grey-brown with darkening on the head, upper surfaces of the wings and tail, while the lower breast and underpart plumages are heavily flecked brown on white.<ref name="ph" />

Their beaks are quite sharp and contain jagged edges. They have fairly short wings resulting in a fast flap rate, but long, tapered tails. While these birds are typically silent, they occasionally make grunting or quacking sounds.

• Female and male S. l. plotus at their stick nest
  Female and male S. l. plotus at their stick nest
• eggs - MHNT
  eggs - MHNT
• Male with chick in São Pedro and São Paulo Archipelago, Pernambuco, Brazil
  Male with chick in São Pedro and São Paulo Archipelago, Pernambuco, Brazil
• feeding S. l. plotus chick
  feeding S. l. plotus chick
• Juvenile S. l. leucogaster, São Tomé and Príncipe
  Juvenile S. l. leucogaster, São Tomé and Príncipe

Ecology

This species breeds on islands and coasts in the pantropical areas of the Atlantic, Indian and Pacific oceans. They frequent the breeding grounds of the islands in the Gulf of Mexico and the Caribbean Sea. With the rise in pollution in the world, brown boobies have been using marine debris to make their nests, with 90.1% of these nest were consisted of plastic, while nests near shipwreck have a high percentage of the wreckage debris.<ref>Template:Cite journal</ref> This bird nests in large colonies, laying two chalky blue eggs on the ground in a mound of broken shells and vegetation, but usually raises just one chick, the second one to hatch being unable to compete for food with its older sibling, or even ejected from the nest by it.<ref>Template:Cite journal</ref> It winters at sea over a wider area.

Brown booby pairs may remain together over several seasons. They perform elaborate greeting rituals, and are also spectacular divers, plunging into the ocean at high speed. They eat mainly small fish (such as flying fish, mullets, halfbeaks, anchovies,<ref name="sta.uwi.edu">Template:Cite web</ref> goatfish, crowned squirrelfish, and Indian mackerels<ref name="animaldiversity.org">Template:Cite web</ref>), squids (including the family Ommastrephidae),<ref name="animaldiversity.org"/> or shrimps<ref name="sta.uwi.edu"/> which gather in groups near the surface and may catch leaping fish while skimming the surface. Along with plunge-diving, some fledglings and adults practice kleptoparasitism, where they steal prey from other seabirds. Brown boobies have even been observed stealing prey from the normally even more piratical great frigatebirds as they transfer food to their young.<ref name="animaldiversity.org"/> 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.

Vagrancy

As a result of global warming, the brown booby has increasingly been moving further north into seas formerly too cold for it. The first record in Great Britain was in 2019, with by 2024 a further 15 subsequent records, including six in 2023 and three in 2024; one even reached 59°21'N at North Ronaldsay in Orkney.<ref>Template:Cite journal</ref>

References

• Template:Cite book
• Template:Cite book

Further reading

• Template:Cite book

External links

• Template:Commons category-inline
• Template:Wikispecies-inline
• Brown booby videos, photos & sounds on the Internet Bird Collection