FORM AND MATERIALS OF THE NEST. 
27 
The form of the nest is not always the same in the same family of 
birds. It is modified very much according to locality, — and in this 
respect great differences are observable between birds of the same tribe 
or genus ; though our former statement always holds good, that the 
nests of a particular species of bird can be distinguished from those of 
another species. The nests of thrushes are not invariably alike ; but 
they can be recognized, at all times, as different from tliose of black- 
birds. The simplest nests are those of birds which breed on tlie 
ground. Next come those of birds content to scratch a small cavity in 
the soil for the reception of their eggs ; in a third and still higher rank 
may be placed the birds which line this cavity with soft substances. 
We meet with a similar order of comparison among the species which 
build in holes, or construct a floating nest. Great differences also are 
to be noted among the tree-builders. Some do nothing more than col- 
lect a heap of dry branches ; others arrange quite an artistic frame- 
work ; others dig out a hollow which they carpet with grass, young 
shoots, hair, feathers, roots ; others 
there are who cover their nests with ■ - •';!', '■■ .'V''' - i 
a kind of roof, and others who con- 
struct a corridor or passage by way of 
entrance. The weaver-birds work 
with vegetable fibres, and stitch their 
woofs together with fine threads, 
which they themselves prepare or 
collect in their wanderings abroad. 
Generally, the nest is constructed 
simply for the reception of the eggs 
and as a cradle for the young; but 
"in the hollow of a it.ek." 
not a few birds — such as the weaver- 
bird of South Africa and the satin bower-bird of Australia — build nests 
of pleasure or winter habitations. The woodpecker sleeps always in 
the hollow of a tree ; and most of the sparrows pass the winter nights 
in dwelling-places warmly lined. 
The female, as we have said, is the builder of the nest, and the 
male lends his aid. This is the rule ; but, like all rules, it has its 
