Masked Booby
Encyclopedia
- "Parasula" redirects here. The fossilFossilFossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
genus established by C.J.O. Harrison is properly called Empheresula.
The Masked Booby, Sula dactylatra, is a large seabird
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
Sulidae
The bird family Sulidae comprises the gannets and boobies. Collectively called sulidas, they are medium-large coastal seabirds that plunge-dive for fish and similar prey. The ten species in this family are often considered congeneric in older sources, placing all in the genus Sula...
. This species breeds on islands in tropical oceans, except in the eastern Atlantic; in the eastern Pacific it is replaced by the Nazca Booby
Nazca Booby
The Nazca Booby, Sula granti, is a booby which is found in the eastern Pacific Ocean, namely on the Galápagos Islands where it can be seen by eco-tourists, and on Clipperton Island...
, Sula granti, which was formerly regarded as a subspecies
Subspecies
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...
of Masked Booby. It is also called the Masked Gannet or the Blue-faced Booby.
A conspicuous and distinct gannet
Gannet
Gannets are seabirds comprising the genus Morus, in the family Sulidae, closely related to the boobies.The gannets are large black and white birds with yellow heads. They have long pointed wings and long bills. Northern gannets are the largest seabirds in the North Atlantic, with a wingspan of up...
-like species, it was proposed for separation in a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Pseudosula, but the Nazca Booby and as it seems also the Brown Booby
Brown Booby
The Brown Booby is a large seabird of the booby family, Sulidae. The adult brown booby reaches about 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...
(S. leucogaster) is a quite close relative.
Classification
First described by French naturalist René-Primevère LessonRené-Primevère Lesson
René Primevère Lesson was a French surgeon, naturalist, ornithologist, and herpetologist.Lesson was born at Rochefort, and at the age of sixteen he entered the Naval Medical School there...
in 1831, the Masked Booby is one of five species of booby in the genus Sula. The Nazca Booby
Nazca Booby
The Nazca Booby, Sula granti, is a booby which is found in the eastern Pacific Ocean, namely on the Galápagos Islands where it can be seen by eco-tourists, and on Clipperton Island...
(S. granti) was formerly regarded as a subspecies
Subspecies
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...
. There are four subspecies
Subspecies
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...
, none of which is separable at sea:
- S. d. personata van Tets, Meredith, Fullagar & Davidson, 1988: Austropacific Masked Booby
- Breeds in the central and western Pacific and around AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, as well as off MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and on Clipperton IslandClipperton IslandClipperton Island is an uninhabited nine-square-kilometre coral atoll in the eastern Pacific Ocean, southwest of Mexico and west of Central America, at...
. Birds of the latter two locations have been separated as subspecies granti, and the NW Australian population has been named as subspecies bedouti, but neither is usually considered valid.
- S. d. dactylatra van Tets, Meredith, Fullagar & Davidson, 1988: Atlantic Masked Booby
- Breeds in the CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and some Atlantic islands including Ascension IslandAscension IslandAscension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
. It has recently started breeding off TobagoTobagoTobago is the smaller of the two main islands that make up the Republic of Trinidad and Tobago. It is located in the southern Caribbean, northeast of the island of Trinidad and southeast of Grenada. The island lies outside the hurricane belt...
, formerly being known in this area only from a single sight record from an oil rigOil platformAn oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily store product until it can be brought to shore for refining and marketing...
off TrinidadTrinidadTrinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...
.
- S. d. melanops van Tets, Meredith, Fullagar & Davidson, 1988: Western Indian Ocean Masked Booby
- Breeds in the western Indian OceanIndian OceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
.
- S. d. tasmani (including S. d. fullagari) van Tets, Meredith, Fullagar & Davidson, 1988: Tasman BoobyTasman BoobyThe Tasman Booby or Lord Howe Masked Booby is a large seabird of the gannet family, Sulidae, described from bones found on Norfolk and Lord Howe Islands in the Tasman Sea...
or Lord Howe Masked Booby
- The form breeding on Lord HoweLord Howe IslandLord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...
and the Kermadec IslandsKermadec IslandsThe Kermadec Islands are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga...
. Large prehistoric specimens known from the former and Norfolk IslandNorfolk IslandNorfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...
are sometimes considered a distinct "species" (properly: subspecies). If this is correct, the extant population's name would be S. d. tasmani as S. d. fullagari was described after S. tasmani. Comparison of ancient DNAAncient DNAAncient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses...
form tasmani specimens and living fullagari indicates that they are not distinct.
Description
This is the largest boobyBooby
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:...
, at 74 – long, with a 137–165 cm (53.9–65 in) wingspan and 1.2–2.35 kg (2.6–5.2 lb) weight. Adults are white with pointed black wings, a pointed black tail, and a dark grey facemask. The sexes are similar, but the male has a yellow bill, and the female's is greenish yellow; during the breeding season they have a patch of bare, bluish skin at the base of the bill. Juveniles are brownish on the head and upperparts, with a whitish rump and neck collar. The underparts are white. Adult plumage is acquired over two years.
The Masked Booby is silent at sea, but has a reedy whistling greeting call at the nesting colonies. While on the breeding grounds, these birds display a wide range of hissing and quacking notes.
Behaviour
Masked Boobies are spectacular divers, plunging diagonally into the ocean at high speed. They mainly eat small fishFish
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...
, including flying fish. This is a fairly sedentary bird, wintering
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, but rarely seen far away from the breeding colonies. However, Caribbean birds occasionally wander north to warm southern Gulf Stream
Gulf Stream
The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean...
waters off the eastern seaboard of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. More remarkably, there have been three Western Palaearctic records of Masked Booby, presumably dactylatra, all from Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
waters, although one of these also entered French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
territorial areas.
Breeding
The Masked Booby nests in small colonies, laying two chalky white eggs on sandy beaches in shallow depressions, which are incubated by both adults for 45 days. In most cases, the first chick will kill its smaller, weaker sibling after it hatches. SiblicideSiblicide
Siblicide is the killing of an infant individual by its close relatives . It may occur directly between siblings or be mediated by the parents. The evolutionary drivers may be either indirect benefits for the genetic viability of a population or direct benefits for the perpetrators...
has been well studied in this species; researchers such as David Anderson have demonstrated that while the boobies can manage to feed two chicks if siblicide is prevented, they do so at a steep penalty to health and future reproductive success.