174 BRITISH BIRDS. 
it also possesses a song both rich, sweet, and varied. It may be heard 
breaking out into snatches of melody as it courses through the air, espe- 
cially the young birds in autumn ; but it often warbles when at rest, either 
sitting on a bare twig or a building. 
The food of the Swallow consists entirely of insects. It feeds perhaps 
more on coleopterous insects than the Martin does—a fact noticed long ago 
by Gilbert White. In proof of this the bird is very often seen to alight in 
fields on heaps of dung, or on turnips, where it catches little beetles ; and 
it not unfrequently alights on the roads, and even on the fields, especially 
in dull windy weather, to pick up these insects, which will not fly in such 
a state of the atmosphere. Sometimes it catches an insect lying on the 
water as it passes rapidly overhead. Gnats are very much sought after 
by this bird, as are also crane-flies, and sometimes dragon-flies. Its 
mouth is filled with a sticky saliva, which holds the insect when caught ; 
and it seems that the bird does not swallow its captures until it has got 
a mouthful. Certainly when the birds are feeding their young they do 
uot return to the nest after capturing each successive fly, but only when 
a considerable number are collected together in a sticky mass in the 
mouth. 
There can be little doubt that the Swallow pairs for life. Unlike so 
many of our migratory small birds, the sexes appear to travel in company 
(in pairs) and return each season to their old haunts. 
The nest of the Swallow is generally placed on the joist which supports 
the rafters of a barn or other outhouse, a few inches below the tiles or 
slates which form the roof. In this position it rests upon the horizontal 
surface of the joist, and is a ring of mud lined with dry grass and a few 
feathers. By far the greater number of Swallows’ nests which I have 
seen in this country have been built in this position and on this model. 
Curiously enough, this is not the case on the continent. There the 
Swallow generally builds against a perpendicular wall, but also only a few 
inches below some horizontal shelf or roof; in this situation the nest is 
in the shape of a quarter of a hollow globe of mud. ‘To increase the 
security of the structure it gladly avails itself of any little projection or 
nail or peg to begin upon. But the usual nest of the Swallow on the conti- 
nent only differs from that of the Martin in having the sides as well as 
the front open instead of built up to the projecting shelf or roof. At the 
railway-station at Rustchuk dozens of Swallows’ and Martins’ nests may 
be seen side by side, and differing only in the manner I have described. 
In the large building where my friend Oberamtmann Nehrkorn stall-feeds 
his cattle, near Brunswick, the roof is supported by iron pillars, and many 
Swallows build their nests under the heavy beams which rest upon them, 
using the iron ring which does duty as a capital to lay the foundation mud 
upon. The continental system approaches nearest to the habits of the 
