ALPINE SWIFT. 299 
almost at an acute angle, or hovering with rapid beat of wing with equal 
ease. It ranges far and wide, appearing in one place and apparently 
remaining until the food-supply is exhausted, then moving on to another. 
Sometimes it hawks for food over the water, and often drinks on the wing. 
It wanders far in the course of a day from its nightly retreat ; but a 
hundred miles or so to this intrepid little bird are of little consequence. 
The cry of the Alpine Swift is shrill and tremulous, differing from that 
of the Common Swift, but quite as loud. It utters its note, which is a 
long-continued trill slightly varied, most frequently when chasing its 
companions through the air, especially in the evening, a habit which is 
quite as conspicuous in this bird as in the Common Swift. Itis not known 
to have a song or musical twitter like the Swallows, unless the chattering 
which precedes its departure on migration may be thus regarded. 
In suitable localities the Alpine Swift is by no means arare bird. There 
are very few passes in the Alps where it may not be seen in summer ; and 
it seems as much at home wheeling amongst the minarets of Stamboul as 
circling round the Gothic spires of Geneva or Berne. 
Dixon describes its habits in Algeria as follows :—“ We saw this fine 
Swift at Constantine and El Kantara. The breeding-place at Constantine 
is partly situated in the stupendous cliffs above the city, and is shared with 
Storks and Falcons, and partly in the crevices of the magnificent natural 
arch of rock above the river Roumnel. The birds live in small colonies, 
and many nests are near to each other. We met with a great number of 
birds flying up and down above the river-bed in a ravine below the city, 
incessantly passing to and fro, and mingling with Common Swifts, Martins, 
and Swallows. The flight of the Alpine Swift is much more rapid and 
powerful than that of the other Swifts; it darts with incredible speed, 
turns and twists, hovers, mounts aloft, and dips down with a rapidity that 
renders attempts to shoot it almost useless. Like the Common Swift the 
altitude of its flight varies exceedingly. Some days it will rise to a great 
elevation almost out of sight, on others it will be seen close to the ground, 
rarely going more than sixty or a hundred yards high. The noble pass of 
El Kantara is another home of the Alpine Swift, and its shrill exhultant 
notes may be heard far up above amongst the almost inaccessible cliffs, 
distinctly audible above the roar of the river below.” 
The food of the Alpine Swift is composed exclusively of insects, which 
it catches on the wing. All the hard parts of its food, such as the wing- 
cases of beetles, are cast up again in the form of pellets, as is the case 
with many insectivorous birds. 
The Alpine Swift generally breeds in the crevices of rocks, though it 
will sometimes make its nest in a church or cathedral tower or in a con- 
venient cranny of some other building. Canon Tristram says that in 
Algeria it breeds in the towers of the mosques as well as in the rocks. 
