548 CORVUS FRUGILEGUS. 



eleven twelfths to an inch and nine twelfths, the greatest 

 breadth about an inch and a quarter. They are of a light 

 greenish-blue, blotched, clouded, spotted, dotted, or freckled 

 with greyish-brown and light purplish-grey, sometimes so 

 closely as nearly to conceal the ground colour. The young are 

 hatched about the middle of April or sooner, when the season 

 is very favourable, although in general Rooks are not much in- 

 fluenced by cold or heat with reference to the period at which 

 they deposit their eggs. 



These birds generally select for their breeding places the 

 clusters of tall trees usually found in the neighbourhood of old 

 family mansions ; and being in this manner indicative of the 

 antiquity of the house to which they have attached themselves, 

 they become objects of interest to its members, and find pro- 

 tection from them. When the trees in such a situation are not 

 numerous, the nests are sometimes crowded upon them in 

 masses, three or four being occasionally contiguous. This 

 season, 1837, there are on three large plane trees on the lawn 

 at Prestonlield, the seat of Sir Robert Dick, twenty-six, twenty- 

 five, and twenty-three nests, and on the neighbouring trees a 

 variable number down to a single nest. But when a large 

 wood is selected, they seldom build so closely, although even 

 there it is not uncommon to find eight or ten on a tree. 

 Rookeries are more numerous in highly cultivated districts, 

 which are at the same time liberally supplied with wood. Al- 

 though usually placed in tall trees, yet they are sometimes seen 

 on such as are by no means remarkable for height, but in the 

 latter case never elsewhere than in parks or pleasure grounds, 

 for it is the experience or sense of security that determines their 

 choice of a breeding place. There are several small rookeries 

 in the heart of Edinburgh, and various authors speak of similar 

 establishments in other cities. Instances of their building on 

 cliffs, towers, and steeples, are also recorded, but they are very 

 unusual. I have seen Jackdaws and Sparrows making use of 

 the deserted nests of rooks, after the young of the latter were 

 flown ; but such occurrences are rare. 



Not having visited a rookery at night, I was desirous of 

 knowing how the birds would conduct themselves when dis- 



