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Darwin Correspondence Project

From J. J. Weir   26 May 1869

6 Haddo Villas | Blackheath SE

26 May 1869

My Dear Sir

I have now made my visit to the Birdcatchers, and find that there is no doubt as to the male of the Nightingale arriving in this country first.—1

One man told me he had received several males this Spring, and it was not till a fortnight after the first, that he had any females, and then he had two, and he said that the same rule held good for the Blackcap.—2

This latter bird is one that is easily recognized in the male sex & I have invariably noticed that the early birds are males, the head of the female has a brown cap, the other warblers are not easily distinguished, but it has always appeared to me that they arrive in full song, and are afterwards joined by the females.—

One of the Chaffinch “Peggers” has this Spring “pegged” in one day the hitherto unparalleled number of 70 birds.—

A match came off a few days since between two experts   one caught 62 & the other 40 birds.—3

There seems no doubt that the males are considerably in excess of the females, and the jealousy of the males makes them fall such an easy prey to these men.—

Chaffinches have but one nest during the year to each female, unless the first has been destroyed.—

I feel very unwilling to differ from you, but as to the fertility of canary mules I think you must have been misinformed, the universal testimony of Fanciers including our mutual friend Wicking is that they are barren.—4

I have heard of but one case of a linnet5 mule breeding ♂ but the testimony was not that of an experienced man.—

I placed two mule hens in my aviary one a Goldfinch & the other a Siskin mule, both Goldfinches ♂ & a Siskin ♂ are with them but I notice no advances on either side.

On the other hand I placed one canary ♀ in the aviary to see out of all the species, Linnets, Goldfinches, Siskin, Greenfinch, Chaffinch’s & others which she would choose, there was never any doubt the Greenfinch carried the day & this morning I observe two young ones hatched.6

You would have been pleased to see how so dull a colored bird as the Greenfinch (chloris), made the most of his generally concealed brighter feathers when courting.— The tail was spread, so as to exhibit the bright yellow outer webs of the feathers, and the wings were drooped to make the most of their golden edgings, the bird singing all the time, however he proved irresistible—

It appears to me that birds which breed but once are more quarrelsome than those which have more

CD annotations

1.1 I have … nest 7.1] crossed ink
2.1 One man … for 2.3] scored blue crayon
2.3 the Blackcap.—] double scored blue crayon
4.1 One … birds.— 4.2] scored blue crayon; top of page ‘Keep for Birds | S Selection’ blue crayon, del pencil; ‘& for Origin crosses’ pencil del pencil; ‘Jenner Weir’ pencil
6.1 There … females,] underl blue crayon; double scored blue crayon
7.1 Chaffinches … destroyed.— 7.2] crossed blue crayon
8.2 Fanciers … barren.— 8.3] crossed ink; cross in right margin, blue crayon; ‘Keep’ top of page, blue crayon, circled blue crayon, del pencil
11.1 On … hatched. 11.4] crossed pencil; ‘p 99’ or ‘p 97’ added and circled pencil; ‘(Keep for chr’ added blue crayon, square bracket in original ms
12.1 You would … irresistible— 12.45 crossed blue crayon
13.1 It appears … more 13.2] crossed blue crayon
Top of letter: ‘Scraps Sexual selection’ ink


See letter to J. J. Weir, 20 May [1869] and n. 2. Weir refers to an area in the East End of London around Club Row, Sclater Street, and Brick Lane in Spitalfields known for its bird dealers and animal traders.
The blackcap is Sylvia atricapilla. In Descent 1: 259, CD cited Weir for this information.
The chaffinch is Fringilla coelebs. In Descent 2: 53, CD explained the practice of ‘pegging’, a method of using caged and stuffed birds to catch male songbirds, and also cited Weir for the information about the number of chaffinches caught in a day (see also Descent 1: 307, n. 47).
In Variation 1: 295, CD had written that the canary had been crossed with nine or ten other species of Fringillidae, of which some hybrids were almost completely fertile. Matthew Wicking had supplied CD with pigeons (see Correspondence vol. 6, letter to W. B. Tegetmeier, 11 February [1857] and n. 4).
The linnet is now Carduelis cannabina.
The goldfinch is now C. carduelis; the siskin is now Carduelis spinus; the greenfinch is Carduelis chloris. In Descent 2: 115, CD cited Weir for the information on the canary choosing the greenfinch male.


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.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Migratory male nightingales and blackcaps arrive before females [see Descent 1: 259].

Discusses chaffinch "Peggers".

Disagrees with CD’s opinion that canary mules are fertile.

Display of colour of greenfinches in courtship.

Letter details

Letter no.
John Jenner Weir
Charles Robert Darwin
Sent from
Source of text
DAR 86: A52a-c, DAR 84.1: 143
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6758,” accessed on 29 September 2020,

Also published in The Correspondence of Charles Darwin, vol. 17