SOCIAL BACKBONED ANIMALS 131 



charm of their own (fig. 1103). The following vivid account 

 given by Dixon (in Among the Birds in Northern Shires) will 

 call up pleasant memories to the minds of many readers: 

 "And then their home in the cluster of elm-trees yonder is a 

 place fraught with interest if full of noise. Towards the close of 

 February, or, if the weather be still inclement, not until the 



Fig. 1103. A Rookery 



beginning of March, and at least a fortnight or three weeks later 

 than in Devonshire, the rooks begin to tidy up their big nests 

 in the slender branches at the tree-tops. Others, less fortunate, 

 commence to build entirely new nests. But this building is by 

 no means universal for a week or more; the mania for collecting 

 sticks and turf has not yet spread through the entire colony, 

 and numbers of birds may be seen looking on with indifference 

 at the efforts of more industrious neighbours. What a noisy 



