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The families of Swifts, Nightjars, and Frogmouths, here classed together, afford an even more difficult case than that of the Anisodactyli, their differences being of so well-marked and important a character as to make it very doubtful whether they can belong to the same order. The hallux in all is connected with the flexor perforans digitorum, and the arrangement of the deep flexors (except in Macropteryx) is Galline, as in Coracias and Buceros; the oil-gland is nude or wanting, the manubrium sterni very small or absent, the coracoids separate, and the number of both primary-quills and tail-feathers 10. The spinal feather-tract is well-defined on the neck, but forked on the upper back. All, too, have a short bill and an excessively broad gape, and all live on insects captured in the air.
The three families Cypselidae, Caprimulgidae and Podargidae form suborders.
The Trochilidae, or Humming-birds of America, are generally placed in this order, but their relations to the Swifts are disputed by a few naturalists. Another American family, Steatornithidae, appears probably allied to the Podargidae.
The other suborders are all Indian, and may be thus distinguished:
a. Palate aegithognathous; no basipterygoid processes; no caeca a nude oil-gland
No caeca. Oil-gland present, but nude. Palate aegithognathous; no basipterygoid processes. No median wing-coverts. Sternum without posterior incisions, the keel high. No semitendinosus muscle. A large aftershaft.
Nidification varies greatly, but all the Swifts lay elongate white eggs, and in all the saliva is used to cement together the materials of the nest and to attach it to some surface. In some forms of Collocalia the nest consists entirely of inspissated saliva. The salivary glands are greatly developed, especially at the breeding- season. The young are hatched naked. A single family.
Bill small, hooked at the end, gape very broad, Wings long, the primaries greatly developed, curved; secondaries very short. Humerus very short. Feet weak, the first or hind toe is more or less reversible, and all four toes are often directed forward in some of the genera.
This family is cosmopolitan, except that it does not occur in Arctic or Antarctic regions. There are three subfamilies, thus distinguished:
a. Tarsus feathered; three anterior toes (2, 3, 4), each with three phalanges; wings extending far beyond tail .. Cypselinae
This includes the typical Swifts, in which the hind toe is completely reversible, and the third and fourth toes have only three phalanges each. Sexes always alike. Two genera are Indian.
Key to the Genera
a. Toes all directed forward as a rule .... CYPSELUS
The true Swifts have the toes as a rule all directed forward, but the first or hinder toe is reversible They are birds of powerful flight, though inferior in this respect to Chaetura. All make nests attached to rocks or buildings, or very rarely to trees.
Key to the Species
a. No white on rump.
* The name Micropus, Meyer and Wolf, 1810, which has one year’s priority over Cypselus has been substituted for the latter by some writers, and especially by Mr. Hartert in the British Museum Catalogue, vol. xvi. But the existence of a Linnaean genus Micropus in Botany affords a fair reason for adhering to the well-known name of Cypselus for typical Swifts, The generic name Micropus (1837) used by Sharpe and Oates (ante, Vol. I. p. 294) for a genus of Bulbuls, is of later date than Meyer and Wolf’s genus, and must be changed to Microtarsus, Eyton (1839).
Coloration: Upper parts,
sides of head and neck, a broad band across the upper breast, and the lower
tail-coverts brown, varying slightly in depth of tint, nearly uniform in old
birds, the feathers darker near the end, and with whitish edges in young
individuals; chin, throat, lower breast, and abdomen white, feathers
sometimes black-shafted; under wing-coverts always with whitish edges,
especially near the bend of the wing.
Size: Length about 8.5; tail 3; wing 8.5; tarsus 0.6. The tail is deeply forked, the outer feathers being about 0.75 inch longer than the middle pair.
Distribution: Europe as far north as the Alps, northern Africa, South-western Asia, India, and Ceylon. This bird is resident, and breeds in the Himalayas, on rocky precipices amongst the Western Ghats, and doubtless in other hilly parts of the Peninsula. The nests and eggs have been taken by Miss Cockburn en the Nilgiris near Kotagiri, and nests have been seen by Mr. Davidson near Nasik, and by Mr. Littledale in Kashmir; whilst the hills of Ceylon (Legge), the cliffs of Gersoppa (Jerdon), Satara (Davidson), and Gawilgurh in Berar (McMaster) have been shown to be probable breeding-places. The Alpine Swift may be seen at times throughout the peninsula, and it has been recorded from Darjeeling and Assam, but not farther east.
Habits: This fine Swift is probably, with the exception of the larger species of Chaetura, the swiftest and most powerful flyer amongst birds. It roosts and breeds in companies on rocky cliffs, but flies enormous distances each day, generally in scattered flocks, and may be found hawking insects in the air hundreds of miles from its roosting-place. It has a shrill cry, often uttered during flight. The nests have walls about an inch thick made of feathers. dry grass, etc., firmly cemented together by the saliva of the birds; they are 4 or 5 inches in diameter, not lined. Several nests are often clustered together. The eggs are laid in Europe about May and June; they are white, elongate, 3 or 4 in number, and measure about 1.2 by 0.75.
Hirundo apus, Linn. Syst. Nat. i, p. 344 (1766)
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