58 THE SENSES OF ANIMALS 



two and then reached up and caught the cuckoo, which I 

 removed to a safer place. 



Whether this most interesting happening has any bearing 

 on the "short neck" theory, it is difficult to say. All I would 

 point out is that the cuckoo was in flight for only a few 

 seconds, but its curved wings were much in evidence, and 

 the reaction of the small birds to the sight of it was instan- 

 taneous. In contrast to the indifference to my cardboard 

 models on the part of the birds around my house, I can state 

 that a little later, when my cuckoo had complete freedom in 

 the garden for three weeks, I never knew the vegetables to 

 be freer from damage. During that three weeks, hardly a 

 bird was to be seen around. 



It is known that certain species of birds react differently 

 to threats to themselves or their eggs and young. Many 

 ground-nesting birds — plovers for instance — go in for a kind 

 of distraction behaviour by appearing to simulate injury, 

 thus diverting the attention of the enemy away from the 

 nest ; but whatever kind of reaction to danger takes place, it 

 is the eyes of the threatened birds that come to their aid. 



Avoidance of danger is not the only reason why a bird 

 relies so much on its eyes. The selection of food, or the mere 

 perception of it, depends upon sharp sight when those birds 

 which feed on either seeds or insects are at work. A creature 

 as small as an aphid can be spotted and eaten in a flash ; an 

 earthworm some distance away, which is out of its burrow, 

 will be seen at once, though when the worm is in its burrow 

 it is the sense of hearing that is all important as will be shown 

 later. 



A piece of simple field observation may be carried out by 

 spending some time watching a kestrel feed. These lovely 

 little birds of prey doubtless take some food which may be 

 near at hand and on the ground — beetles and worms for 

 instance; but the typical feeding behaviour of kestrels is 

 carried out by the bird hovering high up in the sky — as far 

 as two hundred feet being not unusual. From this vantage 

 position the bird can survey a large area of the ground 

 beneath it, and a kestrel may be seen quartering a meadow 

 or a piece of waste-land just like a good gun-dog. 



If the kestrel is watched through binoculars, you may have 



