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Darwin Correspondence Project

From J. J. Weir   [before 28 April] 18681

6 Haddo Villas | Blackheath SE


My Dear Sir

I was in Spitalfields recently & had some further conversation with a bird catcher, he said it was a common thing to catch 6 or 7 male chaffinches from one nest, and further observed that there was a great disproportion of the sexes in Blackbirds, the males being by far the more numerous, they are caught in great numbers by a decoy bird placed in a cage with a trap over it, one man he said had thus caught 60 in a short time, all males, their pugnacity leading to their capture.—2

Yet he observed when they are caught by bat folding the males are still far more numerous than the females.—3

Blackbirds are very pugnacious & cannot be kept in an aviary with other birds   Thrushes have exactly the opposite character.—

I have sometimes thought there was some connection between the beauty of ♂ birds and their pugnacity, and between their pugnacity & the greater commonness of the male sex.—4

Robins however are nearly alike in both sexes, yet they fight in the Autumn, this appears to me to arise from the necessity there is for an insectivorous non-migratory bird to have in the winter a district to itself over which it may succeed in obtaining a subsistence.

The robin is however migratory in some parts of Europe & this very irascible bird is then known to associate in small flocks.—

It would be very interesting to ascertain whether it is as quarrelsome in Northern Europe as in England.—

There is an old Greek proverb which shews it is in Southern Europe—quite as pugnacious.—5

The black hen Bullfinch has succeeded at last in gaining the affections of the male bird, but she had to do all the courting but now they are paired I observe that when he makes his advances he distends his breast feathers so as to make at least one third more of the red color visible in front.—

I have twice reintroduced the old hen, but the dark one still pursues her in the most relentless manner, causing her to take refuge behind a box & there keeping her prisoner for hours.—6

My brother was here yesterday & he has some facts for you, but he has not sufficient leisure at present to write, for fear he may forget to tell you, I may as well say, that, he has ascertained that there are often in Starlings nests as many as nine eggs (9) this I think proves that more than one hen had laid in the nest.—7

Have you seen the case in the Newspapers of a lamb being brought forth with the (W) mark in black wool, which was the flock mark of the owner & was used on the dams side.—8

I have some very curious observations on Ivies which will form the subject of my next letter.—

You can form no idea of the pleasure it gives me to find you are interested in my line of thought.—

Yours very sincerely | J Jenner Weir

C Darwin Esqr

CD annotations

3.1 Blackbirds … pugnacious.— 8.2] crossed ink
9.1 The … in front.— 9.4] crossed blue crayon
12.1 Have … side.— 12.3] crossed blue crayon
13.1 I … thought.— 14.2] crossed pencil
Top of letter: ‘M’ blue crayon
Top of second sheet: ‘M’ blue crayon


The date is established by the relationship between this letter and the letter from J. J. Weir, 28 April–4 May 1868.
For more on Spitalfields, see the letter from J. J. Weir, [26] March 1868 and n. 1. In Descent 1: 306–7, CD cited Weir on the proportion of sexes in chaffinches and blackbirds, noting that the information was from bird catchers.
See Descent 1: 307. ‘Batfolding’, or more commonly ‘batfowling’, was the practice of catching birds at night, using lights to confuse them, and beating the hedges where they were roosting.
In Descent 2: 93, CD cited Weir on the relation of bright plumage and pugnacity.
Weir refers to the Greek proverb ‘one bush does not support two robins’ (for the original Greek and various interpretations of the meaning, see Mynors trans. 1991, p. 87).
For Weir’s acquisition of a black bullfinch, see the letter from J. J. Weir, [before 5] March 1868). In Descent 2: 121, CD referred to Weir’s observations of rivalry between female bullfinches.
Weir refers to Harrison William Weir. In Descent 1: 269, CD cited J. J. Weir on the occupation of the same nest by three starlings.
The source of the information has not been identified. For Weir’s previous mention of marks related to ‘maternal imagination’, see the letter from J. J. Weir, 5 April 1868. See also letter to J. J. Weir, 18 April [1868] and n. 14.


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


Proportion of sexes in chaffinches.

Pugnacity of blackbirds and robins.

Harrison Weir reports up to nine eggs in starling nests.

Newspaper report of a sheep born with its owner’s brand.

Letter details

Letter no.
John Jenner Weir
Charles Robert Darwin
Sent from
Source of text
DAR 86: C1–2, DAR 84.1: 73–4
Physical description
8pp †

Please cite as

Darwin Correspondence Project, “Letter no. 6078,” accessed on 25 September 2021,

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