150 The Bird 
night-hawks brush them into rapacious maws, if per. 
chance they have succeeded in reaching the upper air. 
In tropical forests, where insects are everywhere 
abundant, the birds seemed to have realized the fact that 
to each is apportioned certain phases of insect life, and 
that by hunting in large flocks, instead of competition 
resulting between birds of different species, they play 
into each other’s hands (or rather beaks). It is of such 
a flock that Hudson writes: “The larger creepers ex- 
Fic. 116.—Squid. 
plore the trunks of big trees, others run over the branches 
and cling to the lesser twigs, so that every tree in their 
route, from its roots to the topmost foliage, is thoroughly 
examined, and every spider and caterpillar taken, while 
the winged insects, driven from their lurking-places, are 
seized where they settle, or caught flying by the tyrant- 
birds.” 
The Wattled Starlings or Locust-birds of South Africa 
live in flocks of thousands, and so dependent are they 
on locusts as food, that their habitat and place of nest- 
