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 
starlings 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 | 
‘pall-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 Rig; Raedesralee: 
starlings gradually fill up the 
hollow of the cylinder until they again assume their ‘ball’ 
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. 
“Tn Cape Colony the Locust-birds usually breed in 
very large colonies, in localities in which the locusts have 
