THE COMMON SWIFT. BIRDS. THE COMMON SWIFT. 



281 



whole time is passed in the air in pursuit of the insects 

 on which they feed. Their behaviour in this incessant 

 flight is very similar to that of the still better known 

 swallows, although they display even more activity. 

 To show the rapidity of flight possessed by some of 

 these birds, we may quote a calculation made by Le 

 Vaillant with regard to an African species which he 

 calls the Martinet Velocifere. " In flying," says the 

 African traveller, " it passes over a space of one hundred 

 toises in five seconds, as I have ascertained several 

 times upon a measured ground. Thus, supposing that 

 the bird would or could continue its flight with the 

 same rapidity, it wpuld be scarcely a minute in travelling 

 half a league ; and, consequently, would only take a 

 fortnight in going round the world." 



The Swifts also present some anatomical characters 

 which seem to corroborate the justice of their separation 

 from the Swallows. In the first place, the inferior 

 larynx is destitute of those muscles, by the agency of 

 which singing birds are enabled to modulate their notes, 

 and which are present in the swallows; hence, with 

 those authors who adopt the division of the passerine 

 birds into two great sections, according as they do or 

 do not possess the organs of song, the separation of 

 these two families would become still wider than we 

 have made it. Secondly, there is a difference in the 

 form of the sternum : the Swallows, like all the other 

 singing birds, having the posterior margin of this bony 

 plate deeply notched, whilst in the Swifts it is entire 

 a character which is strongly in favour of the view held 

 by some ornithologists, that the Swifts are really allied 

 to the Humming-birds, which possess a very similar 

 sternum, and present other resemblances too striking 

 to be overlooked. 



The Swifts, like the Swallows, and indeed like most 

 purely insectivorous birds, are migratory in the colder 

 and temperate climates. Our European species arrive 

 here later, and leave earlier, than the Swallows. They 

 usually frequent old walls and buildings, or rocks, in 

 the holes or crevices of which they breed, often without 

 any attempt at building a nest. We now proceed to 

 notice a few of the most remarkable members of this 

 family, commencing with 



THE COMMON SWIFT (Cypselus apus) plate 5, fig. 

 15 as the best known species. In this bird the typical 

 characters of the Swifts are well shown: the small weak 

 bill, the large, oblong nostrils, the extremely long, 

 curved, nearly sabre-shaped wings reaching when 

 closed far beyond the extremity of the slightly-forked 

 tail and the small weak feet, are all exhibited most 

 distinctly by our Common Swift, which also presents 

 another character already referred to, but not common 

 to the other genera of the family, namely, that all the 

 four toes are directed forwards (fig. 105). These charac- 

 ters belong to the typical genus Cypselus. The Common 

 Swift is of a uniform blackish-brown colour, slightly 

 glossed with green, except on the chin, which is occupied 

 by a greyish-white patch. The total length of the bird 

 is about seven inches and a half, and the wings usually 

 extend fully sixteen inches an immense stretch, when 

 we consider the small size and lightness of the body. 



The Swift, as already indicated, is a summer visitor 

 to Europe, and usually arrives in this country about the 



beginning of May. It leaves us again generally by the 

 middle of August, so that its stay in Britain hardly 

 exceeds three months ; and it is remarkable that the 

 birds quit even Italy towards the end of August to cross 

 the Mediterranean on their way to their African winter- 

 quarters. On the continent of Africa our Common 

 Swift is said to advance even to the Cape of Good 

 Hope, although the majority probably stay within the 

 tropics as asserted by Temminck. In Asia these birds 

 are met with as far to the east as lake Baikal, and 

 specimens have been killed in India. Like some other 

 migratory birds, the Swifts will often return after an 

 absence of eight or nine months, and a voyage of 

 several thousand miles through the trackless fields of 

 air, to the very same spot where they had built their 

 nests and reared their young the year before. Dr. 

 Jenner ascertained this with regard to the Swift by an 

 experiment which he describes in the following words : 

 " At a farm-house in this neighbourhood" (Berkeley 

 in Gloucestershire), he says "I procured several 

 swifts ; and, by taking off two claws from the foot of 

 twelve, I fixed upon them an indelible mark. The 

 year following, their nesting-places were examined in 

 an evening when they had retired to roost, and then I 

 found several of the marked birds. The second and 

 third year a similar search was made, and did not fail 

 to produce some of those which were marked. I now 

 ceased to make an annual search ; but, at the expira- 

 tion of seven years, a cat was seen to bring a bird into 

 the farmer's kitchen, and this also proved to be one of 

 those marked for the experiment." 



On its arrival the Swift takes up its abode in holes and 

 other sheltered places in church-steeples, towers, ruins, 

 and under the eaves of houses. From these concealed 

 nooks and corners, it dashes forth in fine weather to 

 wheel about in the air with inconceivable rapidity in 

 pursuit of insects, accompanying its headlong flight 

 with loud screaming notes ; but when the day is 

 unfavourable, and especially when there is a high 

 wind, the Swifts, notwithstanding their power of wing, 

 usually keep close within their snug retreats. Their 

 food consists entirely of insects, which they capture and 

 devour, as previously stated, on the wing. They do 

 not indeed appear always to swallow then* insect prey 

 as soon as it is caught ; but as it usually consists of 

 gnats, midges, and other small compressible insects, 

 they seem to prefer collecting a sufficient number in 

 their mouths before swallowing them, to make it worth 

 their while to do so. The insects caught for the nour- 

 ishment of the young are also carried and collected in 

 the same way, so that it is rarely that a Swift is killed 

 without some insects in its mouth. 



The nest is built in one of the ordinary holes in- 

 habited by the birds. It is composed of fragments of 

 straw, dry grass, and bits of rag, with a few feathers ; 

 and these materials are glued together by degrees, 

 especially after the nest has been inhabited for several 

 successive seasons, by means of a sort of glutinous 

 secretion produced by the largely-developed salivary 

 glands with which the Swifts in general are endowed. 

 The eggs are usually two in number, but vary from 

 two to four, the latter number being rare. The young 

 are hatched about the end of June, but do not leave the 



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