Rooks Diving. 275 
set to work and tear up the grass by the roots over a 
wide space—perhaps nearly half an acre—in search 
of a favourite beetle. The grass is pulled up in little 
wisps, just about as much as they can hold in their 
beaks at atime. In spring they make tracks through 
the mowing-grass—not in all the meadows, but only 
in one here and there, where they find the food they 
prefer. These tracks are very numerous, and do the 
grass some damage. Besides following the furrows 
made by the plough, and destroying grubs, beetles, 
wireworm, and other pests in incalculable numbers, they 
seem to find a quantity of insect food in unripe corn ; 
for they often frequent wheatfields only just turn- 
ing yellow, and where the grain is not yet developed. 
Except perhaps where they are very numerous, they 
do much more good than harm. 
Rooks may now and then be seen in the autumn, 
on the hayricks; they pull the thatch out, and will do 
in this way an injury totheroof. Therefore old black 
bottles are often placed on the thatch in order to 
scare them. It is said that they pull out the straw 
for the stray grains left in the ear by the threshing- 
machine, This seems doubtful. It appears more prob- 
able that some insect found on the straw attracts them. 
If you are walking past a feeding flock, the nearest 
rook to you will often exhibit a ridiculous indecision as 
to whether he shall fly ornot. He stretches his neck 
and leans forward as if about to spring, stops, utters a 
questioning ‘Cawk ?’ then watches you a moment and 
T2 
