44 THE CROW FAMILY 



It is when the hen bird has begun to sit, if not before, that the 

 rooks remain to sleep at the nest instead of returning to the winter 

 roost, but, as is shown by the following interesting record from a 

 rookery in the north, they do not necessarily all make up their minds 

 to remain on one and the same date. On March 9th one pair of birds 

 stayed behind and improved the occasion by pilfering their neigh- 

 bours' nests. On the llth two hens stayed on their nests, their mates 

 departing with the rest to the winter roost. On the 17th half the birds 

 remained to roost, the rest departing as usual. On the 20th only six 

 pair departed. On the 22nd all departed as usual, but did not go far. 

 They returned at a great height, and then swooped down into the 

 nesting trees. On the 28th all stopped to pass the night. 1 



It is now also that from time to time a tragedy occurs which 

 generally results in the break up of the rookery for the season. This is 

 the arrival of a pair or more of carrion-crows, hoodies, or ravens. These 

 enter the nests, peck open and suck the eggs, the rightful owners, after 

 much turmoil and fighting, deserting sometimes at once, sometimes 

 coming back day after day only to be driven off again, not to return till 

 the following year. In one case about half the birds returned to a 

 rookery ravaged in the previous season by a pair of crows. The latter 

 reappeared, and in one day robbed thirty nests, and drove away the 

 owners. The remaining pairs were able to hatch out their young, as 

 one crow was shot and the other disappeared. Shooting the aggressors 

 is the only remedy, and it is advisable to shoot both, for if one 

 escapes, it is as likely as not to return with a new mate. What is most 

 remarkable in these occurrences is the inability of the rooks to defend 

 their nests. A pair of crows, and still more a pair of ravens, owing to 

 their strong bills, are more than a match for a pair of rooks ; but that 

 one or two pairs should force over a hundred pairs of rooks to leave, 

 and successfully oppose their daily attempts to return, is a mystery 

 difficult to explain. That these raids are of fairly frequent occur- 

 rence will be evident from the examples referred to in the footnote, 



1 Prom a record kept in 1908 by Mr. Walter Stewart of Blantyre, N.B. 



