Family Gannets, Boobies (Sulidae)

Least Concern

Masked Booby (Sula dactylatra)


Taxonomy

French: Fou masqué German: Maskentölpel Spanish: Piquero enmascarado
Taxonomy:

Sula dactylatra

Lesson

, 1831,

Ascension Island

.

Until recently considered conspecific with S. granti but breeds sympatrically and assortatively with it, differing in its yellow (not orange) bill and lesser sexual dimorphism; also differs in foraging preference, feeding at sea and not concentrating near shores; and in typical use of flat areas not steep slopes for nesting. Hybridization with S. leucogaster has been recorded. Races vary clinally in size, becoming larger eastwards from Atlantic, with largest forms occurring in E Pacific. Birds of NE Pacific sometimes separated as race californica, but extensive individual variation means no consistent significant differences detected, so best treated as a synonym of personata#R; birds of SE Indian Ocean occasionally separated as race bedouti, but likewise probably indistinguishable from personata. Recently described form fullagari is synonymous with tasmani; latter name was previously applied to a form mistakenly believed extinct (Tasman Booby, S. tasmani), which has now been reclassified on basis of morphological and genetic data as a race of present species#R,#R. Four subspecies recognized.

Subspecies and Distribution
  • S. d. dactylatra Lesson, 1831 – breeds on islands in Caribbean and off N coast of South America (S to E Brazil), on Ascension I (S Atlantic Ocean), and possibly also still in Bahamas.
  • S. d. melanops Hartlaub, 1859 – islands of S Red Sea and W Indian Ocean.
  • S. d. personata Gould, 1846 – breeds in SE Indian Ocean (Cocos Keeling Is, Christmas I and NW Australia), and on numerous islands in W & C Pacific Ocean from Philippines E through Micronesia and Polynesia, N to Hawaiian Is and S to Coral Sea, off NE Australia; also E Pacific on islands off W Mexico (Alijos Rocks, Clarión I, San Benedicto, Clipperton I) and off NC Chile (San Félix, San Ambrosio)#R.
  • S. d. tasmani van Tets et al., 1988 – breeds in N Tasman Sea (Lord Howe I, Norfolk I and Kermadec Is).
  • Descriptive notes

    81–92 cm; male 1400–1500 g, female 1450–1660 g (nominate), male 1300–2211 g, female 1375–2353 g (personata); wingspan... read more

    Voice

    Silent at sea. At breeding colony has reedy whistling greeting call; also on breeding grounds,... read more

    Habitat

    Strictly marine and fairly pelagic. Prefers deeper waters than other boobies. Nests on rocky... read more

    Food and feeding

    Shoaling fish, especially flying-fish (Exocoetidae) up to 28 cm long, generally taking larger prey than other boobies, including fish up to... read more

    Breeding

    Only loosely seasonal throughout most of range. Small to medium-sized colonies of variable density. Nest a simple circle of accumulated... read more

    Movements

    Most adults spend all year within vicinity of colonies. However, young birds and some adults may... read more

    Status and conservation

    Not globally threatened (Least Concern). Population widely dispersed throughout tropical waters and thus very difficult to estimate, but pantropical distribution suggests... read more

    Recommended citation

    Carboneras, C., Christie, D.A., Jutglar, F., Garcia, E.F.J. & Kirwan, G.M. (2017). Masked Booby (Sula dactylatra). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/52623 on 23 November 2017).