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Darwin Correspondence Project

To J. J. Weir   13 March [1868]

4. Chester Place | Regent’s Park | N.W.

March 13th

My dear Sir

You make a very great mistake when you speak of “the risk of your notes boring you”.1 They are of the utmost value to me, & I am sure I shall never be tired of receiving them; but I must not be unreasonable. I shall give almost all the facts which you have mentioned in your two last notes, as well as in the previous ones;2 & my only difficulty will be not to give too much & weary my readers. Your last note is especially valuable about Birds displaying the beautiful parts of their plumage. Audubon gives a good many facts about the antics of birds during courtship;3 but nothing nearly so much to the purpose as yours. I shall never be able to resist giving the whole substance of your last note.—4 It is quite a new light to me except with Peacock & Birds of Paradise: I must now look to Turkeys’ wings; but I do not think that their wings are beautiful when opened during courtship. Its tail is finely banded. How about Drake & Gallus bankiva?5 I forget how their wings look when expanded.— Your facts are all the more valuable, as I now clearly see that for Butterflies I must trust to analogy altogether in regard to sexual selection. But I think I shall make out a strong case (as far as the rather deceitful guide of analogy will serve) in the sexes of Butterflies being alike or differing greatly—in moths which do not display the lower surface of their wings not having them gaudily coloured &c &c.—nocturnal moths &c.—& in some male insects fighting for the females, & attracting them by music.—

My discussion on sexual selection, will be a curious one,—a mere dovetailing of information, derived from you, Bates, Wallace6 &c &c &c.— We remain at above address all this month & then return home. In the summer, could I persuade you to pay us a visit of a day or two & I wd. try & get Bates & some others to come down.7 But my health is so precarious, I can ask no one, who will not allow me the privilege of a poor old invalid; for talking, I find by long & dear-bought experience trys my head more than anything, & I am utterly incapable of talking more than half-an-hour, except on rare occasions.—

Accept my cordial thanks for your extreme kindness & believe me my dear Sir | Yours sincerely | C. Darwin

I fear this note is very badly written, but I was very ill all yesterday & my hand shakes today.


CD refers to the letters from J. J. Weir, 7 March 1868 and 11 March 1868, and to Weir’s earlier letters of [after 27 February] 1868, [before 3] March 1868, and [before 5] March 1868.
John James Audubon discussed the courtship of birds in his Ornithological biography (Audubon 1831–[39]). CD’s annotated copy is in the Darwin Library–CUL (see Marginalia 1: 21–3).
See letter from J. J. Weir, 11 March 1868. CD included Weir’s description of the courtship displays of various finches in Descent 2: 94–5.
CD refers to the male of the common wild duck, Anas boschas (now Anas platyrhynchos, the mallard; see Descent 2: 84), and to Gallus bankiva (now G. gallus, the red junglefowl).
Henry Walter Bates and Alfred Russel Wallace.
According to Emma Darwin’s diary (DAR 242), Weir, Wallace, and Edward Blyth visited CD from 12 September 1868.


Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.


Thanks for facts about birds displaying plumage during courtship; "for Butterflies I must trust to analogy altogether in regard to sexual selection".

Invites JJW to visit in summer.

Letter details

Letter no.
Charles Robert Darwin
John Jenner Weir
Sent from
London, Chester Place, 4
MR 13 68
Source of text
The British Library (Egerton MS 2952: 8–10)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6009,” accessed on 23 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16