154 HABITS OF BIRDS. 
reason that the birds in whose nest the cuckoo para- 
sitically deposites her egg, often, if not always, turn 
out or destroy their own to make room for hers. 
During the process of hatching, the mother-bird 
acts as if she knew that, by keeping the eggs all in 
one position, some would be more favourably treat- 
ed than others. 
Sheltering of the Young.—In rearing tender song- 
birds taken from their mothers, as is frequently 
done, before they are fledged, experience proves that 
warmth is no less indispensable than food ; exposure 
to cold during the night frequently killing the most 
healthy nestlings. The mother-birds, well aware 
of this, are equally assiduous in covering their 
chicks after they are hatched as they had previously 
been while sitting on the eggs. Among small birds 
(Sylvicole, Vieittot), accordingly, for several days 
after her brood has been hatched, the mother sel- 
dom quits the nest, the male providing the food 
necessary for her and the little ones, who as yet 
. require but a very small portion. The wren, and 
other birds which build domed nests, have this ad- 
ditional protection to prevent the dissipation of 
their animal heat; and birds of prey, pigeons, and 
crows, have but a small number of nestlings to 
shelter. 
In the case again of poultry, when the newly- 
hatched birds can run about, the mothers have no 
little trouble in sheltering them from the cold, and, 
even during the hottest weather, from rain, which 
proves very injurious in consequence of the cold 
produced by its evaporation. However much, also, 
we may admire the ingenuity of birds in some 
things, and their anxious affection for their young, 
yet ‘they exhibit in other instances great apparent 
stupidity ; and maternal affection, so far from siiarp- 
ening their faculties, seems at first rather to blind 
them, and to cause them to injure and even to kill 
some of their chickens through awkwardness or in- 
