skip to content

Darwin Correspondence Project

From Bernard Peirce Brent   23 October 1857

Castle Farm | Dallington | nr. Hurst Green | Sussex

October 23r. d. 1857.

Dear Sir,

Yours of yesterday came to hand this morning and now that the children are in bed I take up my pen to answer your inquiries as well as I am able though I fear, I can give but little information;

With respect to breeding Mules from hen Canaries, the only difficulty I have found is to get the cock bird either Goldfinch; Grey Linnet; or Green Linnet; to pair, or associate amicably with the hen canary.1

when this is accomplished I have always found the eggs hatch well even better than from two canaries, frequently every eggs prolific, and the young birds seem to me hardier than the canaries,

When in France I had a hen Goldfinch mule paired with a cock Goldfinch they built and the hen mule laid, the eggs were of various sizes one the smallest about like a small pea and round—one the natural size, the third between. Mice destroyed the nest at Bessel’s Green,2 I put up two hen Goldfinch mules, with a cock canary, and they both, built and laid eggs, but they were not properly paired, and there was no chance of produce, one laid natural eggs, the other varied in size, and one laid two nests— one of these hens reared a young one from eggs given

I have had both Goldfinch mule cocks and Green linnet mule cocks paired with, and tread hen canaries, but no produce, from what I hear and my own experience I believe that these unions are occasionally productive, but it is stated that the mule cock must be paired with its own mother, though I am not an eyewitness to the fact, I have only heard it so affirmed; it is also an axiom with fanciers, that if the hen canary is over four years she will never be fertile with a Goldfinch— 3

Cook-Flower Esqr. a rare old Sportsman with whom I spent many happy days at Calais

CD annotations

crossed pencil
2.2 Goldfinch] underl pencil
2.2 Grey Linnet] underl pencil
2.2 Green Linnet] underl pencil
scored pencil and brown crayon; ‘Q’4 added pencil, circled pencil
3.3 canaries,] ‘All eggs Prolific C. Œne (& reciprocally)’ added pencil
scored brown crayon; ‘Q’added pencil, circled pencil
scored brown crayon; ‘Q’added pencil, circled pencil
crossed pencil


CD cited this information in his chapter on hybridism (Natural selection, p. 429).
Bessels Green, Riverhead, is the first of three addresses recorded for Brent in CD’s Address book (Down House MS).
Brent is cited on this point in Natural selection, p. 431.
‘Q’ stands for quote. See n. 1, above.


Discusses the difficulties of breeding mules by crossing canaries and finches.

Letter details

Letter no.
Bernard Peirce Brent
Charles Robert Darwin
Sent from
Dallington, Sussex
Source of text
DAR 160: 299
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2158,” accessed on 24 August 2019,

Also published in The Correspondence of Charles Darwin, vol. 6