this species, and who lose the young before their change into the adult plumage, will send them promptly to the National Collection.[1]
As regards the acquirement of the adult plumage, some tropical birds are very precocious, but others extremely dilatory. Some of the little Ploceid Finches (such as Amadina fasciata and Tæniopygia castanotis) are in full adult plumage and ready to breed when about six to eight weeks old; thus examples of the former, which left the nest in September, were breeding in October; and it is not uncommon for Zebra Finches (T. castanotis) to build and lay when eight weeks old. Mr. Meade-Waldo, speaking of the Chinese Quail (Excalphatoria sinensis), says: "They were hatched on July 23rd, and were in adult plumage by August 27th."
On the other hand, the Satin Bower-bird is known to be very slow in acquiring its adult plumage; the late Mr. Abrahams used to put the date of change at three years of age, but the Director of the Zoological Gardens, Melbourne, Mr. A.A.C. Le Souëf, says that he "caged a number (at least a dozen), ... and it was only after the expiration of nearly eight years they began to change colour. I think four or five birds put on the beautiful blue-black plumage, and in a year or two died off. It is therefore evident that the birds only come to their full plumage in old age, and that accounts for the fact that in a flock of, say, one hundred birds, which we often used to see at Gembrook some years ago, there would be only a very few, not half a dozen, black ones among them."[2]
It is well known that in many species the flocks which assemble for migratory or other purposes consist wholly of birds of one sex. Two or three years ago (and again this year) the bird-market was flooded with Pekin Nightingales (Liothrix lutea), of which I bought three dozen examples in various conditions of plumage, hoping to secure plenty of males of that charming songster; but all proved to be hens. It is also well known that old hen birds often assume male plumage towards the end of
