(445/2. Quoted in the "Descent of Man" (1901), page 564. "A bullfinch
which had been taught to pipe a German waltz...when this bird was first
introduced into a room where other birds were kept and he began to sing,
all the others, consisting of about twenty linnets and canaries, ranged
themselves on the nearest side of their cages, and listened with the
greatest interest to the new performer.") What kind of birds were these
twenty?

2. Is it true, as often stated, that a bird reared by foster-parents, and
who has never heard the song of its own species, imitates to a certain
extent the song of the species which it may be in the habit of hearing?

Now for a more troublesome point. I find it very necessary to make out
relation of immature plumage to adult plumage, both when the sexes differ
and are alike in the adult state. Therefore, I want much to learn about
the first plumage (answering, for instance, to the speckled state of the
robin before it acquires the red breast) of the several varieties of the
canary. Can you help me? What is the character or colour of the first
plumage of bright yellow or mealy canaries which breed true to these tints?
So with the mottled-brown canaries, for I believe that there are breeds
which always come brown and mottled. Lastly, in the "prize-canaries,"
which have black wing- and tail-feathers during their first (?) plumage,
what colours are the wings and tails after the first (?) moult or when
adult? I should be particularly glad to learn this. Heaven have mercy on
you, for it is clear that I have none. I am going to investigate this same
point with all the breeds of fowls, as Mr. Tegetmeier will procure for me
young birds, about two months old, of all the breeds.

In the course of this next month I hope you will come down here on the
Saturday and stay over the Sunday. Some months ago Mr. Bates said he would