From J. J. Weir   16 March 1868

My Dear Sir

Since my last my Brother has had a long conversation with me about sexual selection in pigeons.—¹

We are both decidedly of opinion that color has little to do with sexual selection in the common pigeon, at the same time it should be noted that the only brilliant colors are found in the iridescent neck, and this the male, as we all know inflates and displays when courting, and the success of his antics in this respect is so great in some birds of very erotic temperament, or what the fanciers call “gay”, that it often is requisite to shut up such a lively male because of the mischief done to the strain amongst the hens to which he is not paired.—²

My Brother further observed that although the pigeons usually pair for life, a very short absence only is necessary to cause them to forget each other, how short he could not say, but when the ♂ & ♀ are separated for a few weeks during the winter in order to pair them differently for the next season, as universally practised by the best fanciers, they rarely if ever recognize each other again; the pairs differently assorted remain as the owner intends them.—

This is curious because the birds will return to the place from which they have been taken even after a period of nine months.—

Thus their memory will last for nine months in one case, but is quite lost in two months in another.—³

In your last note you mentioned the Drake,⁴ this bird has during the breeding season only a very brilliant green head and neck, when courting it is certainly turned to the best advantage, the head is moved rapidly up and down, vulgarly the head is bobbed quickly; at the same time the Drake swims by the side of the duck, but I do not like to go so far as to say that the speculum on the wing is displayed more than usual, indeed I am inclined to think the latter ornament has some other use, it is nearly as bright in the ♀ as the ♂.

I have seen the wigeon in Spring when the flame like color has appeared on the forehead, lay his head down quite close to the water below the head of the ♀, this appears to me to be a case of sexual display.—⁵

When you asked whether other birds beside the Gallinaceæ were polygamous, I presume you had not forgotten the Ruff (Machetes pugnax);⁶ it is most remarkable that in such a very dull colored group as the Tringidæ and the allied family Scolopacidæ,⁷ that the only polygamous species (I believe) should have such marvellous nuptial appendages as the ♂ pugnax, small wart like wattles, and large hackles capable of being erected like a Gallus.—⁸

I have seen the ♂ fight & the attitude was precisely that of a Game Cock, often looking at each other without moving & then suddenly renewing the encounter.— the color of the hackles varies so very much that the tastes of all the hens might be satisfied.

I hope soon to write about the experiments I made last year with caterpillars, but enough for the present.—⁹

It will give me great pleasure to visit you at Down whenever your health will permit.¹⁰

Yours very sincerely | J Jenner Weir

C Darwin Esq.