264 Wild Lifein a Southern County. 
breeze. If too stiff, in strong gales the nest runs the 
risk of being blown clean out of the tree. Fifthly, 
no other branch must rub against the one bearing the 
principal weight of the nest, for that would loosen the 
twigs in time, and dislocate the entire structure. 
Finally, rooks like an adjacent bough on which the 
bird not actually engaged in incubation can perch 
and ‘caw’ to his mate, and which is also useful to 
alight on when bringing food for the young. 
It may be that the difficulty of finding trees which 
afford all these necessary conditions is one reason 
why rooks who settle at a distance from their city 
seem long before they can please themselves. The 
ingenuity exercised in the selection of the bough and 
in the placing of the twigs is certainly very remark- 
able. When the wind blows furiously you may see 
the nest moving gently, riding on the swaying boughs, 
while one of the birds perches on a branch close by, 
and goes up and down like a boat on the waves. 
Except by the concussion of branches beating hard 
against the nest, it is rarely broken; up to a certain 
point it would seem as if the older nests are the 
firmest, perhaps because of their weight. Sometimes 
one which has been blown down in the winter—when 
the absence of protecting leaves gives the wind more 
power on them—retains its general form even after: 
striking against branches in its descent and after 
collision with the earth. | 
Elms are their favourite trees for building in. Oak 
