552 BRITISH BIRDS. 
in winter, when almost starved by a long-continued frost, he will often 
bore into the turnips with his strong beak. Perhaps the most favourite 
feeding-grounds of the Rook are the stubbles, especially when ploughing 
is going on and worms and grubs are to be found in the newly turned up 
soil. When feeding, the Rook is very wary, and a sentinel is usually 
perched on some neighbouring tree to give the alarm on the approach of 
danger. Towards evening, when their appetites are satisfied, they often 
fly round and round, and toy with each other in the air, before setting off 
for their roosting-quarters. 
Towards the end of February they begin to repair their nests. Every 
day they stop longer and longer ; and when the eggs are laid they roost at 
the rookery. Rooks may be tempted to form a new rookery, by putting 
up artificial nests in suitable trees. During the process of building they 
are often very quarrelsome. When the birds break off twigs from the 
nesting-trees, they fly clear of the tree and gain the nest by an uninter- 
rupted course, probably because, were they to convey the twig through 
the tangled branches, it would be an extremely troublesome and difficult 
task. During the building-period one of the birds usually stays to guard 
the unfinished nest whilst its mate is seeking materials ; for Rooks are 
pilfermg birds; but when once the nest is completed it may be left 
with safety. When I was residing at Sheffield I had several Rooks’ nests 
in my garden, my next-door neighbour had fourteen, and there were about 
as many more on the other side of the road—all no doubt forming part of 
the old rookery in Broomhall Park, which must originally have been 
scattered over a mile or more, as there are isolated trees left in the streets 
which are still tenanted with their old occupants every spring. Towards 
the end of February the Rooks began to be very busy about their old 
nests. One year only one nest had survived the storms of winter. The 
birds appeared to have a quarrel about it; and finally it was completely 
pulled to pieces. They fairly began to build in good earnest about the 
lst of March, when they might be seen, sometimes three or four in a tree 
at once, tugging at the twigs and breaking off a piece, which they often 
transferred from their beaks to their claws, apparently to rest from the 
exertion of breaking it off. They seemed to be very quarrelsome all the 
time they were building, continually stealing twigs from each other’s 
nests. Once they fought so desperately that one poor Rook fell down 
dead. It was no uncommon thing to see a good foundation for a nest 
laid by breakfast-time, and to find not a vestige remaining at noon. Both 
parents assist in the duties of incubation; and Dixon assures me that he 
has repeatedly seen them change: places on the nest. 
The nest is composed outwardly- of sticks, varying in thickness from 
slender twigs to branches more ‘than half an inch in diameter, and is 
cemented with mud and clay and lined with large masses of turf, a few 
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