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Darwin Correspondence Project

To J. J. Weir   7 May [1868]1

Down. | Bromley. | Kent. S.E.

May 7.

My dear Sir

I have now to thank you for no less than 4 letters!2 You are so kind that I will not apologize for the trouble I cause you; but it has lately occurred to me that you ought to publish a paper or book on the habits of the birds which you have so carefully observed. But shd you do this I do not think that my giving some of the facts for a special object wd much injure the novelty of your work. There is such a multitude of points in these last letters that I hardly know what to touch upon. Thanks about the instinct of nidification, & for your answers on many points.3 I am glad to hear reports about the ferocious female bullfinch.4 I hope you will have another try in colouring males.5 I have now finished Lepidoptera & have used your facts about caterpillars, & as a caution the case of the yellow underwings.6 I have now begun on fishes, & by comparing different classes of facts, my views are getting a little more decided. In about a fortnight or 3 weeks I shall come to birds & then I dare say that I shall be extra-troublesome.7

I will now enclose a few queries for the mere chance of your being able to answer some of them, & I think it will save you trouble if I write them on a separate slip, as then you can sometimes answer by a mere No or yes.

Your last letter on male pigeons & linnets has interested me much, for the precise facts which you have given me on display are of the utmost value for my work.8 I have written to Mr Bartlett on gallinacæ but I dare say I shall not get an answer.9 I had heard before, but am glad to have confirmation about the ruffs being the most numerous.10

I am greatly obliged to your brother for sending out circulars. I have not heard from him as yet.11 I want to ask him whether he has ever observed when several male pigeons are courting one female, that the latter decides with which male she will pair.

The story about the black mark on the lambs must be a hoax.12 The inaccuracy of many persons is wonderful. I shd like to tell you a story, but it is too long, about beans growing on the wrong side of the pod during certain years.13

What a number of points you have attended to: I did not know that you were a horticulturist. I have often marvelled at the different growth of the flowering & creeping branches of the Ivy; but had no idea that they kept their character when propagated by cuttings. There is a S. american genus (name forgotten just now) which differs in an analogous manner but even greater degree; but it is difficult to cultivate in our Hot-house.— I have tried & failed.—14 It is very surprising to me that the arrangement or phyllotaxis of the leaves shd change. Revd G. Henslow has just been writing on this subject & shd. hear of your fact.—15 The variegation of leaves is enough to perplex anyone.—

Your kindness & assistance is beyond thanks, so I will not attempt it.

My dear Sir | Yours very sincerely | Ch. Darwin



Does any female bird regularly sing?

Do you know of any case of both sexes, more especially of the female, which is more brightly coloured whilst young than when come to maturity & fit to breed? An imaginary instance wd be if the female Kingfisher (or male) became dull coloured when adult.—

Do you know whether the male & female wild Canary bird differ in plumage (tho’ I believe I cd find this out for myself) & do any of the domestic breeds differ sexually?

Do you know any gallinaceous bird in which the female has well developed spurs?


The year is established by the relationship between this letter and the letter from J. J. Weir, [4–7] May 1868.
Weir had written four letters to CD since CD’s last letter to him: see letters from J. J. Weir, 20 April 1868, [before 28 April] 1868, 28 April – 4 May 1868, and [4–7] May 1868.
In his letter to Weir of 18 April [1868], CD had asked Weir’s opinion of Alfred Wallace’s view that birds learned to make nests from having seen them while young. Weir’s reply is in his letter to CD of 20 April 1868.
See letters to J. J. Weir, 27 February [1868] and 29 February [1868], and letter from J. J. Weir, [before 5] March 1868; see also letter from Harrison Weir, 28 March 1868. No further observations by the Weirs on the subject have been found.
CD cited Weir’s remarks on the rejection of certain caterpillars by birds in Descent 1: 417 (see letter from J. J. Weir, 24 March 1868). In Descent 1: 395, CD cited Weir’s account of a common yellow underwing moth, Triphaena pronuba (now Noctua pronuba), whose coloured wings so distracted a robin that the moth was not caught, though its wings were damaged (see letter from J. J. Weir, [before 5] March 1868).
According to CD’s ‘Journal’ (Correspondence vol. 16, Appendix II), he began working on the section on birds for Descent on 17 May 1868.
See letter to J. J. Weir, 4 April [1868] and n. 4. The letter to Abraham Dee Bartlett has not been found.
The Gardeners’ Chronicle, 27 April 1861, p. 390, reported that there was a ‘foolish notion’ abroad that the growth of the beans of the previous year was different from that of other years, in that the beans hung down in the pod, rather than being erect; according to the Gardeners’ Chronicle, ‘some of those who insisted on the difference appealed to the position of the suture’. The eccentric growth was thought to coincide with the beginning and the end of the potato blight. See also Correspondence vol. 9, letter to Robert Chambers, 30 April [1861] and n. 6.
George Henslow’s paper on phyllotaxis was read at the Linnean Society in April 1868 (Henslow 1868); see also letter from George Henslow, 13 April 1868. For CD’s own interest in phyllotaxy, see Correspondence vol. 11.


Climbing plants: On the movements and habits of climbing plants. By Charles Darwin. London: Longman, Green, Longman, Roberts & Green; Williams & Norgate. 1865.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

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


Thanks JJW for his great assistance.

Discusses sexual selection in birds.

Sends queries on secondary sexual characteristics of birds.

Has often marvelled at the different growth of the flowering and creeping branches of ivy.

Letter details

Letter no.
Charles Robert Darwin
John Jenner Weir
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6165,” accessed on 25 September 2020,

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