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 Velocifire. “ 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 would 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 gi'eat 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 cliin, 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 
w'e 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 
VoL. I. 36 
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 tlie 
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 
Sw'ift 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 Lave been killed in India. Like some other 
migratory birds, the Swifts will often retinm after an 
absence of eight or nine months, and a voyage of 
several thousand miles through tlie trackless fields of 
air, to the very same spot where they' had built their 
nests and reared their ymung 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 
ymar 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. E rom 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 vung, 
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 their 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 ymung 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 neat 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 
