10 THE AUSTRALIAN NATURALIST. 
ahs EN Arar a: us narnghanapeauaaneunepe) A spilt BE. AM 
bronze cuckoos, are very distinct with regard to appearance, 
song, and colouration of their eggs. The largest—the pallid 
‘cuckoo—which is often dubbed the stormcock or mosquito 
hawk, has a rollicking call running up the scale, and lays an 
egg of a light buff colour, sometimes slightly spotted. The 
fan-tailed cuckoo has a monotonous rolling whistle, is easily 
distinguished by its rufous breast, and lays a pinkish-white 
‘egg, spotted with brown. The brush cuckoo has a peculiar 
song—all its own—which it is easier to imitate than describe. 
Its egg is white with a zone of brownish red spots. The 
bronze cuckoos can only be distinguished at close range, the 
narrow-billed species having aline of grey round the margin of each 
feather on the back, whilst the bronze cuckoo has one continuous 
spread of metallic green. The note of the smaller bird is the 
same wailing whistle, but he is more talkative, and repeats his 
note in a subdued tone—a fact useful to collectors in the field. 
The female of the larger bird is touched with the metallic 
colour; but Mrs. Narrow-bill has no trace of lustre. Their 
eggs, however, are very distinct, one being olive in color, the 
other white, spotted all over with red. 
To turn to the parastic habit, there is only one weak hypo- 
thesis available for its origin; but students of evolution will 
know what slight variations have become perpetuated to the 
advantage of certain species, and will perhaps be able to 
follow this frail argument. It is a well-known fact that certain 
birds, either from stupidity or carelessness, occasionally lay 
their eggs in other birds’ nests. It is surmised then that the 
beginning of the cuckoo habit rose from some such accident. A 
primitive cuckoo was too tired to go home, or too indolent to 
sit on her egg, so she just dropped it in someone else’s nest, 
glad to be rid of it. To her astonishment, the other bird 
hatched her egg for her; leastways, she would have been 
astonished if she could have reasoned it out. Anyhow, the 
instinct to foist off the egg on some other species gradually 
increased in force, until finally all the cuckoos adopted the 
créche system, and left their prospective and material infants 
out while they went about their business. 
Thabis all we can say about the acquisition of the habit. 
With regard to the method of placing the egg, a controversy 
- has raged over a large number of years, some people asserting 
that the cuckoo lays in the foster nest in the ordinary way, and 
Mr. North, our own ornithologist, still believes this, as far as I 
ean judge from his remarks in the catalogue at present being 
issued from the Australian Museum; others that the bird lays 
‘its egg on the ground, and carries it in its mouth to the foster 
nest. The latter view is now generally accepted; yet, in spite 
-of the number of observers in the field, and though one or two 
persons claim to have seen the operation performed, no reliable 
