Frigatebird

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For the nuclear test codenamed Frigate Bird, see Operation Dominic I and II.
Frigatebirds
Male Frigate bird.jpg
Magnificent frigatebird
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Suliformes
Family: Fregatidae
Degland & Gerbe, 1867
Genus: Fregata
Lacépède, 1799
Species
Fregata distribution.png
Range map

The frigatebirds (also known as Fregatidae) are a family of seabirds. They have long wings, tails, and bills and the males have a red gular pouch that is inflated during the breeding season to attract a mate. Their plumage is predominantly black. There are five living species, all in a single genus Fregata, found across all tropical and subtropical oceans. They are absent from polar regions. Long placed in the Pelecaniformes, they are now reclassified in the order Suliformes and appear to be only distantly related to pelicans. The frigatebird family is the sister group to the Suloidea (cormorants, darters, and gannets and boobies). Three fossil species of the prehistoric Eocene genus Limnofregata are known from North America. These had longer legs, less-hooked bills and shorter wings, and at least two of them lived in a freshwater habitat.

Frigatebirds are pelagic piscivores that obtain most of their food on the wing. A small amount of their diet is obtained by robbing other seabirds and by snatching seabird chicks. Frigatebirds are seasonally monogamous, and nest colonially. A rough nest is constructed in low trees or on the ground on remote islands. A single egg is laid each breeding season.

Etymology[edit]

The word frigatebird derives from the French mariners' name for the bird La Frégate - a frigate or fast warship.[1] The etymology was mentioned by French naturalist Jean-Baptiste du Tertre when describing the bird in 1667.[2] In the Caribbean frigatebirds were called Man-of-War birds by English mariners. This name was used by the English explorer William Dampier in his book An Account of a New Voyage Around the World published in 1697:[3]

The Man-of-War (as it is called by the English) is about the bigness of a Kite, and in shape like it, but black; and the neck is red. It lives on Fish yet never lights on the water, but soars aloft like a Kite, and when it sees its prey, it flys down head foremost to the Waters edge, very swiftly takes its prey out of the Sea with his Bill, and immediately mounts again as swiftly; never touching the Water with his Bill. His Wings are very long; his feet are like other Land-fowl, and he builds on Trees, where he finds any; but where they are wanting on the ground.[3]

The modern name Frigate Bird was used in 1738 by the English naturalist and illustrator Eleazar Albin in his A Natural History of the Birds. The book included an illustration of the male bird showing the red gular pouch.[4]

Taxonomy[edit]

Frigatebirds were grouped with cormorants, and sulids (gannets and boobies) as well as pelicans in the genus Pelecanus by Linnaeus in 1758 in the tenth edition of his Systema Naturae. He described the distinguishing characteristics as a straight bill hooked at the tip, linear nostrils, a bare face, and fully webbed feet.[5] The genus Fregata was defined by French naturalist Bernard Germain de Lacépède in 1799.[6] Veillot described the genus name Tachypetes in 1816 for the great frigatebird. The genus name Atagen was coined by Paul Möhring in 1752, though this has no validity as it predates the official beginning of Linnaean taxonomy.[7]

In 1874, English zoologist Alfred Henry Garrod published a study where he had examined various groups of birds and recorded which muscles of a selected group of five[a] they possessed or lacked. Noting that the muscle patterns were different among the steganopodes (classical Pelecaniformes), he resolved that there were divergent lineages in the group that should be in separate families, including frigatebirds in their own family Fregatidae.[8]

In 1994 the family name Fregatidae, cited as described in 1867 by French naturalists Côme-Damien Degland and Zéphirin Gerbe, was conserved under Article 40(b) of the International Code of Zoological Nomenclature in preference over the 1840 description Tachypetidae by Johann Friedrich von Brandt.[9]

The type species is the Ascension frigatebird (Fregata aquila).[10] Frigatebirds, cormorants, darters, tropicbirds and gannets and boobies were long classified in the order Pelecaniformes. But pelicans, the namesake family of the Pelecaniformes, are actually more closely related to herons, ibises and spoonbills, the hamerkop and the shoebill than to the remaining members. In recognition of this, the order was renamed Suliformes in 2010.[11][12]

A cladistic study of the skeletal and bone morphology of the classical Pelecaniformes and relatives found that the frigatebirds formed a clade with the Eocene fossil frigatebird-like genus Limnofregata. Birds of the two genera have 15 cervical vertebrae, unlike almost all other Ciconiiformes, Suliformes and Pelecaniformes, which have 17. This group is sister group to the group Suloidea, which comprises the gannets and boobies, cormorants and darters. The age of Limnofregata indicates that these lineages had separated by the Eocene.[13]

Fossil record[edit]

The Eocene frigatebird genus Limnofregata comprises birds whose fossil remains were recovered from prehistoric freshwater environments, unlike the marine preferences of their modern-day relatives. They had shorter less-hooked bills and longer legs, and longer slit-like nasal openings.[14] Three species have been described: two from the Green River Formation (48-52 million years old) and one from the Wasatch Formation (between 53 and 55 million years of age).[15]

Fossil material indistinguishable from living species dating to the Pleistocene and Holocene has been recovered from Ascension Island (for F. aquila),[16] Saint Helena Island,[17] and various islands elsewhere in the Pacific Ocean (for F. minor and F. ariel).[18][19]

Living species and infrageneric classification[edit]

For many years, the consensus was to recognise only two species of frigatebird, with larger birds as F. aquila and smaller as F. ariel. The Australian ornithologist Gregory Mathews delineated five species, which remain valid.[20][21] Analysis of ribosomal and mitochondrial DNA indicated that the five species had diverged from a common ancestor only recently—as little as 1.5 million years ago. There are two species pairs, the great and Christmas Island frigatebirds, and the magnificent and Ascension frigatebirds, while the fifth species, the lesser frigatebird, is an early offshoot of the common ancestor of the other four species.[21]





Great frigatebird (Fregata minor)



Christmas frigatebird (Frigata andrewsi)





Magnificent frigatebird (Fregata magnificens)



Ascension frigatebird (Fregata aquila)





Lesser frigatebird (Fregata ariel)



Cladogram based on Kennedy and Spencer (2004)[21]

Living species of frigatebirds
Common and binomial names Image Description Range
Magnificent frigatebird
(Fregata magnificens)
Fregata magnificens -Galapagos, Ecuador -male-8 (1).jpg Largest species with body length of around 100 cm (39 in). The adult male is all-black with a scarlet throat pouch that is inflated like a balloon in the breeding season. Although the feathers are black, the scapular feathers produce a purple iridescence when they reflect sunlight, in contrast to the male great frigatebird's green sheen. The female is black, but has a white breast and lower neck sides, a brown band on the wings, and a blue eye-ring. Widespread in the tropical Atlantic, breeding colonially in trees in Florida, the Caribbean and Cape Verde Islands. It also breeds along the Pacific coast of the Americas from Mexico to Ecuador, including the Galápagos Islands.
Ascension frigatebird
(Fregata aquila)
Male Frigatebird with chick Fregata aquila.jpg Boatswain Bird Island just off Ascension Island in the tropical Atlantic Ocean. vulnerable
Christmas frigatebird
(Fregata andrewsi)
Christmas Island Frigatebird.JPG Male: Only species with white on belly - an egg shaped patch. Larger with a longer bill than Great. Upper surface black with green metallic gloss on the mantle and scapulars. Female: Upper surface dark with brown wing bars. Head black with white belly and white collar (sometimes incomplete) around neck.[22] Christmas Island in the Indian Ocean. Critically endangered
Great frigatebird
(Fregata minor)
Male greater frigate bird displaying.jpg Male: Underneath completely black with subtle brown barring on the axillaries. Upper surface black with green metallic gloss on the mantle and scapulars. Female: Upper surface dark with lighter brown wing bars. Head black with mottled throat and belly. White collar around neck.[22] Tropical oceans worldwide
Lesser frigatebird
(Fregata ariel)
Lesser frigatebird lei.jpg Smallest species, body length of around 75 cm (30 in). Male: Black underneath except for bold white axillary spurs. Upper surface black with greenish to purple metallic gloss on the mantle and scapulars. Female: Upper surface dark with lighter wing bars. Head black with white belly and white collar around neck.[22] Tropical and subtropical waters across the Indian and Pacific Oceans. Atlantic race trinitatis limited to Trindade, off Eastern Brazil.[23]

Description[edit]

Male magnificent frigatebird in the Galapagos Islands
(Fregata magnificens) flying at North Seymour Island in the Galapagos

Frigatebirds are large, with iridescent black feathers (the females have a white underbelly), with long wings (male wingspan can reach 2.3 metres (7.5 ft)) and deeply forked tails. The males have inflatable red-coloured throat pouches called gular pouches, which they inflate to attract females during the mating season.

As members of Pelecaniformes, frigatebirds have the key characteristics of all four toes being connected by the web, a gular sac (also called gular skin), and a furcula that is fused to the breastbone. Although there is definitely a web on the frigatebird foot, the webbing is reduced and part of each toe is free. Frigatebirds produce very little oil and therefore do not land in the ocean. The gular sac is used as part of a courtship display and is, perhaps, the most striking frigatebird feature.

Distribution and habitat[edit]

Frigatebirds are found over tropical oceans and ride warm updrafts. Therefore, they can often be spotted riding weather fronts and can signal changing weather patterns.

Behaviour and ecology[edit]

These birds do not swim and cannot walk well, and cannot take off from a flat surface. Having the largest wingspan to body weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week, landing only to roost or breed on trees or cliffs.

Breeding behavior[edit]

They generally lay one white egg per clutch.[24] Both parents take turns feeding for the first three months but then only the mother feeds the young for another eight months. It takes so long to rear a chick that frigatebirds cannot breed every year. It is typical to see juveniles as big as their parents waiting to be fed. When they sit waiting for endless hours in the hot sun, they assume an energy-efficient posture in which their head hangs down, and they sit so still that they seem dead. But when the parent returns, they will wake up, bob their head, and scream until the parent opens its mouth. The hungry juvenile plunges its head down the parent's throat and feeds at last.

Distribution and identifying characteristics differ among frigatebird species, and thus are addressed in species-specific articles.

The duration of parental care in frigatebirds is among the longest for birds, rivalled only by the southern ground hornbill and some large accipitrids.[25]

Feeding[edit]

An immature great frigatebird snatching a sooty tern chick dropped by another frigatebird

Frigatebirds' feeding habits are pelagic. Lacking the ability to take off from water, they snatch prey from the ocean surface or beach using their long, hooked bills. They catch fish, baby turtles, the marine iguana, and similar items in this way. Frigatebirds will rob other seabirds such as boobies, tropicbirds, and shearwaters of their catch, using their speed and manoeuvrability to outrun and harass their victims until they regurgitate their stomach contents. Although frigatebirds are renowned for their kleptoparasitic feeding behaviour, kleptoparasitism is not thought to play a significant part of the diet of any species, and is instead a supplement to food obtained by hunting.[26] A study of great frigatebirds stealing from masked boobies estimated that the frigatebirds could at most obtain 40% of the food they needed, and on average obtained only 5%.[27]

Frigatebird hunting[edit]

In Nauru, catching frigatebirds was an important tradition. It is still practised to a lesser degree. Donald W. Buden writes: "Birds typically are captured by slinging the weighted end of a coil of line in front of an approaching bird attracted to previously captured birds used as decoys. In a successful toss, the line becomes entangled about the bird’s wing and bringing [sic] it to ground."[28]

See also[edit]

Notes[edit]

  1. ^ ambiens, fermorocaudal, accessory femorocaudal, semitendinosus, and accessory tendinosus

References[edit]

  1. ^ Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 164. ISBN 978-1-4081-2501-4. 
  2. ^ Jean-Baptiste, du Tertre (1667). Histoire générale des Antilles habitées par les François (in French). Volume 2. Paris: Thomas Joly. p. 269, Plate p. 246. 
  3. ^ a b Dampier, James (1699) [1697]. An Account of a New Voyage Around the World. London: James Knapton. p. 49. 
  4. ^ Albin, Eleazar (1738). A Natural History of the Birds. Volume 3. p. 75 and plate 80 on previous page. 
  5. ^ Linnaeus, C (1758). Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. Tomus I. Editio Decima, Reformata (in Latin). Holmiae: Laurentii Salvii. pp. 132–34. Rostrum edentulum, rectum: apice adunco, unguiculato. Nares lineares. Facies nuda. Pedes digitís omnibus palmatis. 
  6. ^ Meyer, Ernst; Cottrell, G William, eds. (1979). Checklist of birds of the world. Volume 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 159. 
  7. ^ Australian Biological Resources Study (26 August 2014). "Family FREGATIDAE Degland & Gerbe, 1867". Australian Faunal Directory. Canberra, Australian Capital Territory: Department of the Environment, Water, Heritage and the Arts, Australian Government. Retrieved 30 November 2014. 
  8. ^ Garrod, Alfred Henry (1874). "On Certain Muscles of Birds and their Value in Classification". Proceedings of the Zoological Society of London 42 (1): 111–23. 
  9. ^ Bock, Walter J (1994). History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History Issue 222. p. 131. 
  10. ^ Australian Biological Resources Study (29 July 2014). "Genus Fregata Lacépède, 1799". Australian Faunal Directory. Canberra, Australian Capital Territory: Department of the Environment, Water, Heritage and the Arts, Australian Government. Retrieved 30 November 2014. 
  11. ^ Chesser, R Terry; Banks, Richard C; Barker, F Keith; Cicero, Carla; Dunn, Jon L; Kratter, Andrew W; Lovette, Irby J; Rasmussen, Pamela C; Remsen, JV Jr; Rising, James D; Stotz, Douglas F; Winker, Kevin (2010). "Fifty-First Supplement to the American Ornithologists' Union Check-List of North American Birds". The Auk 127 (3): 726–744. doi:10.1525/auk.2010.127.4.966. 
  12. ^ "Taxonomy Version 2". IOC World Bird List: Taxonomy Updates – v2.6 (Oct 23, 2010). 2010. Retrieved 29 November 2014. 
  13. ^ Smith, Nathan D. (2010). "Phylogenetic analysis of Pelecaniformes (Aves) based on osteological data: Implications for waterbird phylogeny and fossil calibration studies". PLoS ONE 5 (10): e13354. doi:10.1371/journal.pone.0013354. PMC 2954798. PMID 20976229. 
  14. ^ Mayr, Gerald (2009). Paleogene Fossil Birds. New York, New York: Springer Science & Business Media. pp. 63–64. ISBN 9783540896289. 
  15. ^ Stidham, Thomas A. (2014). "A new species of Limnofregata (Pelecaniformes: Fregatidae) from the Early Eocene Wasatch Formation of Wyoming: implications for palaeoecology and palaeobiology". Palaeontology: 1–11. doi:10.1111/pala.12134. 
  16. ^ Ashmole, NP (1963). "Sub-fossil bird remains on Ascension Island". Ibis 103: 382–389. doi:10.1111/j.1474-919X.1963.tb06761.x. 
  17. ^ Olson, Storrs L. (1975). "Paleornithology of St. Helena Island, South Atlantic Ocean". Smithsonian Contributions to Paleobiology 23: 1–49. 
  18. ^ James, Helen F. (1987). "A late Pleistocene avifauna from the island of Oahu, Hawaiian Islands". Documents des laboratories de Géologie, Lyon 99: 221–30. 
  19. ^ Steadman, David W. (2006). Extinction and biogeography of tropical Pacific birds. Chicago: University of Chicago Press. ISBN 978-022677142-7. 
  20. ^ Mathews, GM (1914). "On the species and subspecies of the genus Fregata". Australian Avian Record 2 (6): 117–121. 
  21. ^ a b c Kennedy, Martyn; Spencer, Hamish G (2004). "Phylogenies of the frigatebirds (Fregatidae) and tropicbirds (Phaethonidae), two divergent groups of the traditional order Pelecaniformes, inferred from mitochondrial DNA sequences". Molecular Phylogenetics and Evolution 31 (1): 31–38. doi:10.1016/j.ympev.2003.07.007. 
  22. ^ a b c James, David J (2004). "Identification of Christmas Island, Great and Lesser Frigatebirds". BirdingASIA 1: 22–38. 
  23. ^ Orta, J; Garcia, EFJ; Kirwan, GM; Boesman, P. "Lesser Frigatebird (Fregata ariel)". In del Hoyo, J; Elliott, A; Sargatal, J; Christie, DA; de Juana, E. Handbook of the Birds of the World Alive. Lynx Edicions. Retrieved 30 November 2014. (subscription required)
  24. ^ Howard, Laura. "Family Fregatidae". University of Michigan Museum of Zoology – Animal Diversity Web. Retrieved 29 November 2014. 
  25. ^ Skutch, Alexander Frank; Gardner, Dana (illustrator) (1987). Helpers at Birds' Nests : a worldwide survey of cooperative breeding and related behavior. Iowa City: University of Iowa Press. pp. 69–71. ISBN 0-87745150-8. 
  26. ^ Schreiber, Elizabeth A; Burger, Joanne (2001). Biology of Marine Birds. Boca Raton, Florida: CRC Press. ISBN 0-8493-9882-7. 
  27. ^ Vickery, JA; Brooke, M de L (1994). "The kleptoparasitic interactions between Great Frigatebirds and Masked Boobies on Henderson Island, South Pacific". Condor 96 (2): 331–340. JSTOR 1369318. 
  28. ^ Buden, Donald W (2008). "The birds of Nauru". Notornis 55: 8–19. 

Cited text[edit]

  • Harrison, Peter (1988). Seabirds: An Identification Guide. London: Christopher Helm. ISBN 0-7470-1410-8. 

Further reading[edit]

  • O'Brien, RM (1990). "Family Fregatidae frigatebirds". In Marchant, S; Higgins, PG. Handbook of Australian, New Zealand & Antarctic Birds. Volume 1: Ratites to ducks; Part B, Australian pelican to ducks. Melbourne: Oxford University Press. p. 912. ISBN 978-019553068-1. 

External links[edit]