13 



will for the most part enable us tu determine the species ; and 

 though we might not readily believe the eggs of the Tree Pipit 

 to belong to the same species, we shall have no difficulty in 

 referring them to the right genus. 



In places where those materials are to be met with which 

 instinct has taught individuals of the same species of bird to 

 make use of in the construction of their nests, we shall usually 

 find the same adopted. I know of no other bird which seems 

 80 much to consult its own taste in this respect, as the Com- 

 mon Wren. The materials of its nest are as different as the 

 situations in which it is placed. It may be found built en- 

 tirely of clover, and in places where moss is abundant ; its 

 interior is also formed according to the taste of the owner, 

 and is as often found without any lining at all, as it is thickly 

 lined w'ith feathers. 



There are many instances in which circumstances have led 

 to a deviation from the usual habit. Those Eagles and Hooded 

 Crows inhabiting the Shetland Islands, which would build 

 their nests of sticks, were such materials to be had, are there 

 compelled to substitute the larger species of sea weed. A 

 Carrion Crow which resorted to the Fern Islands to breed, for 

 the same reason, (the absence of sticks) made its nest in a 

 hole in the ground, surrounding it, to give it sufficient depth, 

 with a wall of sods. 



There are a few deviations from the usual instinct, which, 

 not being influenced by local causes, are very remarkable ; 

 and in no instance which has come under my notice, more so 

 than in the nest of a Blackbird, sent me by my friend, the 

 Rev. W. D. Fox, which is lined with black hair, instead of 



