IX 
WARNING COLORATION AND MIMICRY 
263 
poisonous snake which belongs also to the Elapida?. This 
is, no doubt, a warning to its foes, not an attempt to 
terrify its prey; and the hood has been acquired, as in the 
case of the rattlesnake, because, protective coloration being- 
on the whole useful, some mark was required to distinguish 
it from other protectively coloured, but harmless, snakes. 
Both these species feed on active creatures capable of escaping 
if their enemy were visible at a moderate distance. 
Mimicry among Birds. 
The varied forms and habits of birds do not favour the 
production among them of the phenomena of warning colours 
or of mimicry ; and the extreme development of their instincts 
and reasoning powers, as well as their activity and their 
power of flight, usually afford them other means of evading 
their enemies. Yet there are a few imperfect, and one or 
two very perfect cases of true mimicry to be found among 
them. The less perfect examples are those presented by 
several species of cuckoos, an exceedingly weak and de¬ 
fenceless group of birds. Our own cuckoo is, in colour and 
markings, very like a sparrow-hawk. In the East, several 
of the small black cuckoos closely resemble the aggressive 
drongo-shrikes of the same country, and the small metallic 
cuckoos are like glossy starlings; while a large ground- 
cuckoo of Borneo (Carpococcyx radiatus) resembles one of 
the hue pheasants (Euplocamus) of the same country, both in 
form and in its rich metallic colours. 
More perfect cases of mimicry occur between some of the 
dull-coloured orioles in the Malay Archipelago and a genus of 
large honey-suckers—the Tropidorhynchi or “ Friar-birds.” 
These latter are powerful and noisy birds which go in small 
flocks. They have long, curved, and sharp beaks, and power¬ 
ful grasping claws; and they are quite able to defend them¬ 
selves, often driving away crows and hawks which venture to 
approach them too nearly. The orioles, on the other hand, 
are weak and timid birds, and trust chiefly to concealment 
and to their retiring habits to escape persecution. In each 
of the great islands of the Austro-Malayan region there is a 
distinct species of Tropidorhynchus, and there is always along 
with it an oriole that exactly mimics it. All the Tropidorhynchi 
