STOLEN MATERIALS 205 



entrance, may have seemed to him like any other 

 chink or cavity, which he would have been prepared 

 to enter on general principles of investigation. 

 Nests, however, in process of building by one bird, 

 are looked at by others as useful supplies of 

 material for their own — little depots scattered over 

 the country. I have seen a pair of hedge-sparrows 

 fly straight to a blackbird's, and then on, with grass 

 in their bills. Another blackbird's nest, the build- 

 ing of which I was watching, supplied a blue tit 

 with moss, whilst, in the very same tree, a pair of 

 golden-crested wrens had theirs entirely demolished 

 by an unfeeling hen chaffinch. 



In my own experience it is the hen chaffinch, alone, 

 that builds the nest, and I have even seen her driving 

 away a cock bird, which I took to be her mate. 

 After putting him to flight, this particular hen made 

 fifteen visits to the nest, at intervals of about ten 

 minutes, bringing something in her beak each time, 

 and worked at it, singly, with great fervour and 

 energy. To the actions which I have been describ- 

 ing in the long-tailed tits — viz. pressing herself down 

 in it, ramming forward with her breast, kicking out 

 with her feet, behind, and so on — actions, I suppose, 

 common to most nest-building birds — she added 

 that one of clasping the rim tightly with her tail, 

 bent strongly down for the purpose, which I have 

 referred to, before, in the blackbird. I could not, 

 however, repeat the comments which I have made 

 when describing it in her case. Whatever may 

 have been the origin of the habit, it has become, 

 in the chaffinch, a mere business-like affair — purely 

 utilitarian, doubtless, in its inception and object. 



