IN PAIRING TIME 141 



sides of it formed the principal nesting lines for many 

 years, but the head-piece having now also been 

 largely occupied, one pair have built their nest in a 

 small birch tree in a neighbouring villa garden. At 

 the angles of the Pi are two immense nests ancestral 

 structures, as I take it and whilst these are being 

 overhauled, large numbers of the birds sit around 

 them, as if these nests were objects of general interest, 

 and all expected to share them when completed. 



Sticks are first carried during the last week of 

 February, but nest-building in the colony is not over 

 until toward the end of April. A few birds begin to 

 sit during the third week in March, and incubation 

 is still proceeding in the rookery toward the end of 

 May. During this time the cock bird has to redeem 

 his matrimonial pledges. Stick-breaking and the 

 fighting-off of pushful young birds, marauders, and 

 certain solitaries that seem as yet to have no settled 

 status in the colony, at first keep him fully employed. 

 Afterwards, he must away down into the fields to get 

 food for his nest-ridden partner. You may see him 

 return with bulging throat ; and the hen, who can 

 distinguish him from any other rook when still a 

 considerable distance from the nest, immediately upon 

 sighting him, springs on to a bough, and caws 

 frantically as he approaches. Alighting, he gives up 

 his mouthful of delicacies to his partner, who refrains 

 from shrieking only when engaged in extracting the 

 food from his bill and swallowing it. It is obviously 

 but a platitude to say that, but for this sacrifice on 

 the part of the male, the female bird would be 

 unable to discharge her maternal duties ; but, if one 

 reflects how absorbing is the search for food in birds 



