The Food of Birds 



151 



ing is influenced by the presence or absence of these in- 

 sects. ''When pursuing a flight of mature locusts these 

 starUngs perform various extraordinary and beautiful 

 aerial evolutions with the object of intercepting and sur- 

 rounding a portion of the swarm, and in doing this their 

 movements closely resemble those of another locust- 

 destroying starling, the beautiful rose-coloured Pastor 

 of eastern Europe and Asia. Individually the two species 

 are very different; collectively and under similar condi- 

 tions their actions are quite 

 similar. Starting in a dense 

 ' ball-like ' mass, they suddenly 

 open out into a fan-shaped 

 formation, then assume a 

 semicircular arrangement, and 

 finally end by forming a 

 hollow cylinder in which a 

 portion of the locusts are 

 enclosed; as the imprisoned 

 insects are destroyed, the 

 starlings gradually fill up the 



hollow of the cylinder until they again assume their *balP 

 formation and proceed to follow the remaining locusts. 

 The ground below the flock is covered with the droppings 

 of the birds and the snipped-off legs and wings of locusts. 

 At other times the starlings station themselves on the 

 tops of bushes and trees, from which they dart on the 

 flying insects like flycatchers. 



''In Cape Colony the Locust-birds usually breed in 

 very large colonies, in localities in which the locusts have 



Fig. 117.— Rattlesnake. 



