140 TROPICAL SAVANAS 
In Australia and the neighbouring regions two other 
types of running birds occur, these being the emus and 
cassowaries, which resemble the rheas in having three 
toes, but of these the cassowaries are forest birds, 
rarely venturing out into the open. The emu, on the 
other hand, is a savana bird, haunting the plains and 
open country, where it eats a large amount of grass. 
The remaining living member of the group, the kiwi of 
New Zealand, like the cassowary, is an inhabitant of 
wooded districts. 
Another interesting group of birds which inhabit the 
grassy plains of South America, though extending also 
into forest regions, are the tinamus, which show certain 
resemblances to ostriches, but possess the power of 
flight. They strongly resemble game birds in outward 
appearance, being popularly called partridges, but they 
do not fly nearly so well as the game birds, and rise 
with reluctance, preferring to skulk among the long 
grass. The flight is swift, but cannot be kept up for 
long at a time. 
Among other birds characteristic of savana regions 
mention may be made of the bustards, of which many 
species occur in Africa, just as the common form occurs 
in the steppe regions of Asia. The curious secretary 
bird (Serpentarius secretarius) also, with its long legs, is 
very characteristic of the African savanas. Though 
it is capable of flying well and strongly, it prefers to 
run along the ground, like the ostrich. Its structure 
shows that it is allied to the birds of prey, and the fact 
that the young are very helpless, and are for long 
unable to run upon their elongated legs, suggests that 
the ground-haunting habit is a recent acquisition. The 
nest is a huge structure and is often placed in a mimosa 
bush. 
