THE COMMONER BIRDS OF OUR GARDENS. 



431 



Small areas of crops as of maize may be protected by strings placed 

 zigzag two or three feet above the ground, the rook being afraid of 

 being entrapped ; but this is rather expensive. 



Rooks live in flocks, build their nests in the highest trees, often in 

 elms, preferably in the vicinity of buildings. From three to six eggs are 

 laid. Yarrell observes that early in the morning rooks visit meadows while 

 the grass is yet wet with dew to feed on worms and slugs ; later in the 

 day they search the new-ploughed land for insects exposed, or again visit 

 the pastures for other purposes. Rooks frequently associate with starlings 

 and with gulls. 



Miss Ormerod mentions the rook eating surface caterpillars, including 

 Plusia gamma (Silver Y moth), Agrdtis exclamationis (Heart and dart 

 moth), Agrotis segetum (Turnip moth) ; also the May bug (Melolontha 

 vulgaris). 



The Hungarian Central Office of Ornithology in 1905 printed a 

 pamphlet entitled " The Economical Importance of the Rook." It com- 

 menced work by sending out query sheets to which a thousand replies 

 were received. It next dealt with the analysis of stomach contents, in 

 order to endeavour to obtain the complete biography of the rook from 

 month to month, so as to arrive at its agricultural significance. For 

 this purpose it examined 470 stomach contents and several thousand 

 castings from several hundred stations in Hungary. The principal points 

 for observation being : " What is its behaviour towards cereals and corn 

 at the time of sowing and maturity ? Is this damage balanced by the 

 destruction of obnoxious insects ? What part does the rook play in stock- 

 raising ? Ought we to protect our smaller birds against its depredations ? 

 Can one prevent him doing damage ? " 



It was found that the rook fed in the first place on insects and mice, 

 but that from spring to autumn, and on cold, wet days of the warmer 

 season he eats vegetable food as well. 



At sowing and harvest time, unless the cornfields are guarded, it 

 causes every year and everywhere great damage. It, however, particularly 

 in the fall and early spring, consumes many insects (Gryllotalpa, Cleonus, 

 Otiorhynchus), just at a period when the large majority of our insecti- 

 vorous birds are in their winter quarters. To its young it brings enormous 

 quantities of insects and larvae (including Melolontha and its larva?), of 

 the caterpillar of the common dart — Agrotis — of Curculionidae, Dorcadion, 

 and Gryllus. It pulls up cereals and corn sprouts when attacked by 

 wire worm (Elateridae) and white grubs (Chafers). At the time of pests 

 of mice, three and even five mice, with an average of two, have been 

 found in every rook's stomach. 



Game-raising in Hungary is said to be in no way compromised by 

 the rook ; herein he differs from the carrion-crow (Corvus corone) and 

 the hooded crow (Corvus comix). He never attacks young hares, and 

 never destroys birds' eggs. # It has been proved by experience that small 

 game and singing birds multiply undisturbedly even in the neighbourhood 

 of strong colonies. 



* In England and Scotland they are found to interfere with young poultry and 

 pheasants, and with eggs. 



