TROPIC-BIRD, so called of sailors from early times,[1] because as W. Dampier (Voyages, i. 53) among many others testifies, it is “never seen far without either Tropick”; hence, indulging a pretty fancy, Linnaeus bestowed on it the generic term, continued by modern writers, of Phaethon, in allusion to its attempt to follow the path of the sun.[2] There are certainly three well-marked species of this genus, but their respective geographical ranges have not yet been definitely laid down. All of them can be easily known by their totipalmate condition, in which the four toes of each foot are united by a web, and by the great length of the two middle tail-quills, which project beyond the rest, so as to have gained for the birds the name of “Rabijunco,” “Paille-en-queue” and “Pijlstaart” among mariners of different nations. These birds fly to a great distance from land and seem to be attracted by ships, frequently hovering round or even settling on the mast-head. Their flight is performed by rapid strokes, unlike the action of other long-winged sea-fowl, and they are rarely seen on the water.
The yellow-billed tropic-bird, P. flavirostris or candidus, appears to have habitually the most northerly, as well, perhaps, as the widest range, visiting Bermuda yearly to breed there, but also occurring numerously in the southern Atlantic, the Indian, and a great part of the Pacific Ocean. In some islands of all these three it breeds, sometimes on trees, which the other species are not known to do. However, like the rest of its congeners, it lays but a single egg, and this is of a pinkish white, mottled, spotted, and smeared with brownish purple, often so closely as to conceal the ground colour. This is the smallest of the group, and hardly exceeds in size a large pigeon; but the spread of its wings and its long tail make it appear more bulky than it really is. Except some black markings on the face (common to all the species known), a large black patch partly covering the scapulars and wing-coverts, and the black shafts of its elongated rectrices its ground colour is white, glossy as satin, and often tinged with roseate. Its yellow bill readily distinguishes it from its larger congener P. aethereus, but that has nearly all the upper surface of the body and wings closely barred with black, while the shafts of its elongated rectrices are white. This species has a range almost equally wide as the last; but it does not seem to occur in the western part of the Indian Ocean. The third and largest species, the red-tailed tropic-bird, P. rubricauda or phoenicurus, not only has a red bill, but the elongated and very attenuated rectrices are of a bright crimson red, and when adult the whole body shows a deep roseate tinge. The young are beautifully barred above with black arrow-headed markings. This species has not been known to occur in the Atlantic, but is perhaps the most numerous in the Indian and Pacific oceans, in which last great value used to be attached to its tail-feathers to be worked into ornaments.[3]
That the tropic-birds form a distinct family, Phaethontidae, of the Steganopodes (the Dysporomorphae of Huxley), was originally maintained by Brandt, and is now generally admitted, yet it cannot be denied that they differ a good deal from the other members of the group[4]; indeed St G. Mivart in the Zoological Transactions (x. 364) hardly allowed Fregata and Phaethon to be steganopodous at all; and one curious difference is shown by the eggs of the latter, which are in appearance so wholly unlike those of the rest. The osteology of two species has been well described and illustrated by Alph. Milne-Edwards in A. Grandidier's fine Oiseaux de Madagascar (pp. 701-704, pls. 279-281a). (A. N.)
- ↑ More recently sailors have taken to call it “Boatswain-bird”—a name probably belonging to a very different kind. (See Skua.)
- ↑ Occasionally, perhaps through violent storms, tropic-birds wander very far from their proper haunts. In 1700 Leigh, in his Nat. Hist. Lancashire (i. 164, 195, Birds, pl. i., fig. 3), described and figured a “Tropick Bird” found dead in that county. Another is said by Mr Lees (Zoologist, 2nd series, p. 2666) to have been found dead at Cradley near Malvern—apparently before 1856 (J. H. Gurney, jun., op. cit., p. 4766)—which, like the last, would seem (W. H. Heaton, op. cit., p. 5086) to have been of the species known as P. aethereus. Naumann was told (Rhea, i. 25) of its supposed occurrence at Heligoland, and Colonel Legge (B. Ceylon, p. 1174) mentions one taken in India 170 m. from the sea. The case cited by Degland and Gerbe (Ornith. européenne, ii. 363) seems to be that of an albatross.
- ↑ A fourth species, P. indicus, has been described from the Gulf of Oman, but doubt has been expressed as to its validity (Legge, pp. 1173, 1174).
- ↑ Sulidae (Gannet), Pelecanidae (Pelican), Plotidae (Snake-bird). Phalacrocoracidae (Cormorant,) and Fregatidae (Frigate-bird).