HEADS AND TAILS 201 



gradually, higher, in the side of the nest — though 

 this, too, I am inclined to attribute to the mere 

 love of building. The bird builds everywhere that 

 it can, and thus the place where it enters gets 

 higher, with the rest of the nest. When, however, 

 the top of the nest, on one side, is pulled over, so as 

 to meet the other side,^ where the entrance is, it 

 can go no higher, since, if it did, the bird would 

 either be kept in or out. Thus, as it appears to 

 me, the exact position of the hole in the nest, 

 which is a somewhat curious one, is philosophically 

 accounted for. 



When one of a pair of long-tailed tits enters the 

 nest, he first pays attention to that part of it which 

 is exactly opposite to him, as he does so. This he 

 raises with his beak, and, also, by pushing with his 

 head and breast. He then, often, disappears in the 

 depths of the cup, and you see the sides of it swell 

 out, now in one place and now in another, as he 

 butts and rams at them, which he does not only with 

 his head, but by kicking with his legs, behind him. 

 Then he turns round, the long tail appearing where 

 the head has lately been, whilst the head emerges, 

 projecting over the rim in exactly the same place 

 as where he entered, but looking, now, outwards. 

 This part he now pushes down with his chin, just 

 as he raised the other with his head and beak, and 

 having done this, he comes out. But often, sitting 

 in the nest as he entered it, he turns his head right 



^ This, in itself, has the appearance of design only. The bird, 

 however, works from within, and, if I mistake not, there would be 

 a growing tendency for the structure, as it rose in height, to bend 

 over inwards rather than outwards. 



