Family PHAETHONTIDAE Brandt, 1839

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Family PHAETHONTIDAE Brandt, 1839

Phaethontidae Brandt, J.F. 1839. Beiträge zur Kenntniss der Naturgeschichte der Vögel mit besonterer Beziehung auf Skeletbau und vergleichende Zoologie. Mémoires de l'Académie Imperiale des Sciences de St. Petersbourg Ser. 6. Sci. Math. Phys. Nat. 58(2; Sci. Nat. 3): 91-237 + 18 plates [113] (Conserved in the Official List of Family-group Names in Zoology or in the Official List of Generic Names in Zoology. Op. 278) [original spelling].
Type genus:
Phaethon Linnaeus, 1758 [Phaëthon Linnaeus, 1758, Systema Naturae, Ed. 10, vol. 1, p. 134 (gender: masculine) (type species, by designation by Gray, 1840 (List Genera Birds: 80): Phaëthon aethereus Linnaeus, 1758, Systema Naturae, Ed. 10, vol. 1, p. 134) (Aves). Op. 67 phaeton, Papilio, Drury, [1773], Ill. nat. Hist., 1: index, 42, pl. 21, figs. 3, 4♀ (specific name of the type species of Euphydryas Scudder, 1872) (Insecta, Lepidoptera). Op. 278].
Secondary source:
Bock, W.J. 1994. History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History 222: 1-281 [131].
Phaetonidae Bonaparte, C.L. 1853. Classification ornithologique par series. Comptes Rendus de l'Academie des Sciences. Paris 37(18): 641-647 [643].
Type genus:
Phaëton Linnaeus, 1758.

Introduction

Phaethontidae (tropicbirds) is currently recognised as a family (Sangster 1997; Kennedy & Spencer 2003; Bourdon et al. 2005; and Christidis & Boles 2008) with, apparently, no close relatives. Previously they were included among the Pelecaniformes but, unlike members of that order, they lack a gular patch or sac. As the name implies the family has a nominally warm tropical to subtropical pelagic, migratory, distribution with three species in a single genus Phaeton. Two are represented in Australia as regular inhabitants and represented here by four subspecies. A third species, P. aethereus, has recently been identified on Lord Howe Island. Tropicbirds are highly mobile, travelling singly or in pairs. About their breeding grounds they occur in larger numbers. Vocalisations, described as ‘shrill screams’ or 'whistle and rasping’ are generally restricted to the vicinity of their nest. Tropicbirds are gregarious during courtship. Groups of six to 12 may gather when breeding; at sea they are generally seen alone or in pairs.

There are no sexual differences in plumage or morphology. Tropicbirds are medium sized, varying from 25-45 cm. Their wings are long and pointed and their legs and feet are short. Although the principal colour is white, it may carry lightly either a rose or apricot flush. Also there are small patches of black about the superciliary and orbit, tail shafts and flight feathers. Immatures have fine barring across the back. Each species has long and attenuate red or white central tail streamers, red in P. rubicunda and white in P. lepturus, otherwise the tail is short and wedge shaped. These elongate streamers are used in courtship displays. The short legs are situated well back towards the tail and they are very poor walkers; able to move only by employing short sliding motions. The toes of all species are pamprodactyl and totipalmate, yet despite this toe webbing, all species swim poorly. Their slightly decurved, pointed and distinctively coloured bills appear large in comparison to the body; bill colouration varies between species, being yellow in P. lepturus or orange-red in the other species. They have variously patterned markings on the face, back, and wings, while their young are banded on the back with narrow black markings.

The diet of the group is confined to marine organisms (fish, squid, and crustaceans). Prey are obtained by the birds first hovering then diving, often from considerable heights. When not breeding the birds will regularly travel great distances from land in order to feed.

Tropicbirds nest offshore on either high, steep cliff ledges or cavities or in a scrape on the ground. No nest is constructed, the simple scrape being the extent to which the birds go. Larger species of the genus breed annually, while smaller species vary their breeding. A single egg forms the clutch which is incubated by either adult. The egg is ovoid, and has a buff base colour overlaid by red-brown to deep purple blotching. Both adults incubate the egg for a period of between 40 and 46 days and later attend to feeding and caring for the single nidicolous and altricial young which is clothed in grey to fawn down. The young remain in the nest until able to fly.