My dear Sir

I am glad to hear your opinion on the nest-making-instinct, for I am Tory enough not to like to give up all old beliefs. Wallace’s view is, also, opposed to a great mass of analogical facts.— The cases which you mention of suddenly reacquired wildness seem curious.²

I have, also, to thank you for a previous valuable letter. With respect to spurs on ♀ Gallinaceæ, I applied to M^r. Blyth, who has wonderful systematic knowledge, & he tells me that the ♀ Pavo muticus & Fire-back pheasants are spurred.—³ From various interruptions I get on very slowly with my Bird M.S. but have already often & often referred to your volume of letters, & have used various facts, & shall use many more.⁴ And now I am ashamed to say that I have more questions to ask; but I forget, you have told me not to apologise.—

(1) In your letter of April 14^th you mention case of about 20 Birds which seemed to listen with much interest to an excellent piping bull-finch.— What kinds of birds were these 20?⁵

(2) Is it true, as often stated, that a bird reared by foster-parents, & 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 & 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 vars. of the Canary.—⁶ Can you help me?

What is 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 & mottled.— Lastly in the “prize-canaries”, which have black wing & tail-feathers during their first(?) plumage, what colours are the wings & tail after the first(?) moult or when adult? I sh^d. 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 M^r Tegetmeier will procure for me young birds, about 2 months old, of all the breeds.—⁷

In the course of this next month, I hope you will come down here on the Saturday & stay over the Sunday. Some months ago M^r Bates said he would pay me a visit, during June, & I have thought it would be pleasanter for you to come here, when I can get him, so that you would have a companion, if I get knocked up, as is sadly too often my bad habit & great misfortune.⁸

With cordial thanks for your never failing kindness | My dear Sir | Yours sincerely | Ch. Darwin

Did you ever hear of the existence of any sub-breed of the Canary, in which male differs in plumage from the female.—