THE HOUSE MARTIN. 275 
midday seems to dry the mud so rapidly that it cannot be rightly kneaded 
together. ‘The mouths, or “spouts,” of these nests vary from eight to ten 
inches in length, and point indifferently in all directions. The diameter of 
the widest portion of the nest is very variable, and ranges between four and 
seven inches. ; 
The exterior of the nests is as rough as that of the common swallow of 
England, but the interior is comparatively smooth, and is lined with feathers 
and fine grass. The eggs are generally four or five in number, and the bird 
rears two broods in the course of the year. 
THE pretty little SAND MARTIN is, in spite of its sober plumage and 
diminutive form, a very interesting bird, and one which adds much to the 
liveliness of any spot where it may take up its abode. 
In size it is less than any other British Hirundinide, being less than five 
inches in total length. The colour of this bird is very simple, the general 
tint of the entire upper surface of the head and body being a soft brown, 
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HOUSE MARTIN.—(Chelidon urbica.) 
relieved from too great uniformity by the sooty black quill feathers of the 
wings and tail. The under surface is pure white, with the exception of a. 
band of brown across the upper part of the chest. The young bird possesses 
a lighter plumage than the adult, owing to the yellowish white tips of the 
back, tertiaries, and upper coverts. The beak is dark brown, and the eyes 
hazel. 
Although its little beak and slender claws would seem at first sight to be 
utterly inadequate for the performance of miner’s work, the Sand Martin is 
in its way as good a tunnel driver as the mole or the rat, and can manage to 
dig a burrow of considerable depth. The soil which it most loves is light 
sandstone, because the labour which is expended in the tunnelling is very 
little more than that which would be required for softer soils, and the sides 
of its burrow are sufficiently firm to escape the likelihood of breaking down. 
The depth of the burrow is extremely variable, some tunnels being only 
eighteen inches or two feet deep, while others run to a depth of nearly five 
feet. During some five years’ experience and constant watching of these 
T2 
