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Darwin Correspondence Project

From W. D. Fox   [before 14 May 1868]1

see any but pairs.

We used—a few years since, to have Great Numbers of Magpies in the Forest. Up to the National Marriage in early spring—you see all numbers together—but afterwards every Bird has its mate—& I never saw an odd Magpie under any circumstances.2

The Keepers remark about partridges—of never seeing unpaired ones is similar.3 There may however be pairs (to speak Hibernice) of males & females in all Birds—who not having met a suitable match, keep together for Company.4

I was much surprised a few weeks since, on going into a Canary Breeders room—to see 5 Hens put to one Cock, & all apparently Breeding well. He told me—that the Cock only pairs with one Hen, & will only feed her—or her young ones—but that the others are Concubines, to whom he pays the necessary attentions of Love, but does not trouble himself about them or their concerns & that they have to build their nests & rear their young themselves.

The same thing occurs with wild ducks under domestication, & when only removed by one or 2 generations from perfect liberty. The Drake as a rule pairs, but is very salacious after other ducks besides his Wife.

It is commonly said that the Wild Duck & Guinea Fowl pair,—But both are willing to keep Concubines, & both do much better in fact, with 2 females than with one.5

One great difficulty often strikes me in this matter. What of pheasants Turkeys &c &c where one Male has many hens. The Sexes seem abt equal—& certainly are as much so, in these birds—as in those who strictly pair.

By the way—the extraordinary earliness of this Season was shewn by the fact of the week ending May 9—a Pheasants nest with 16 eggs in was found in Forest.

Now what becomes of all the Cock Pheasants &c—if the sexes are about equal. Here shooting the Males of course helps the difficulty—& some few Birds kill each other fighting for their loves in Spring—but these are very few.

I imagine the extra Cock Birds in Pheasants get driven from the best haunts—& that a kind hearted hen (perhaps not herself happy in her conjugal relations) pairs with him, & perhaps in their native country they pair much more than here.

I have observed Birds all my life, & never saw an odd Bird in Spring or Summer—except when I have (to my shame be it spoken) killed one of a pair—& then you only observe the widowed Bird for a day or two, & then it disappears.

There are some Birds which you could not help seeing, if they were lonely Birds—viz Carrion Crows—Magpies—Wood pigeons—Fly catchers.

I never saw a rogue Pheasant—driven, as they say Rogue Elephants are from the herd. Stags are said to be often—or always—thus driven from the Herds by the stronger ones—but I fancy they go to the herds of fawns—or herd together as you see in Parks.

I was amused by a writer in the Field some months since—saying “that it was most fortunate there were much fewer female Wolves in Russia than males, or the Country wd be eaten up by them”— he exemplified his fact by the Nos of males in pursuit of one female.

One wd suppose any one who saw Bitches in same state—wd have had sense enough to come to a truer conclusion.

Are not Black Game6 polygamous as well as Pheasants?

Do “females allure the Males” in Birds— It always seems to me as if an irresistable impulse drives the males to seek the female—especially in Birds.

I have sometimes thought that a strong argument might be drawn against your Theory—when extreme about the Origin of Species (I quite agree with you except when, as I think you get into extremes) when you look at the extraordinary differences in the mode & organs of procreation.

Each Genus—or Family—seems to have its own peculiar mode of procreation & the Organs for it—so essentially different. Look at Cats—Dogs—horses—Cows—. Did you ever see the Organ of the Male Rhinoceros? I imagine you might throw all animals into good Natural Groups merely by this one part of their structure & mode of using it, with its accompanying gestation.

And does not this also separate Man from the rest of creation? All other female Creatures have their seasons only of Love— This seems to me to separate us much more than any anatomical detail, from the Apes &c—.

In Birds the mode of generation is same

CD annotations

2.1 We used … for Company. 3.3] crossed pencil
2.2 but afterwards … circumstances. 2.3] scored blue crayon
4.2 He told me … themselves. 4.6] scored blue crayon
5.1 The same … with one. 6.2] crossed ink; scored blue crayon
7.1 One great … pair. 7.3] crossed red crayon
7.1 Turkeys] underl red crayon
8.1 By … Forest. 8.2] crossed pencil
9.1 Now what … happy 10.2] crossed ink
10.2 in her … in Parks. 13.4] crossed pencil
11.1 I have … disappears. 11.3] scored blue crayon
13.1 I never … in Parks. 13.4] scored blue crayon
14.3 he exemplified … one female. 14.4] double scored blue crayon
16.1 Are not … in Birds. 17.2] crossed pencil
18.1 I have … Apes &c—. 20.3] crossed blue crayon


The date is established by the relationship between this letter and the letter to W. D. Fox, 14 May [1868].
CD had asked Fox about the mating habits of magpies in his letter of 25 February [1868]. The ‘national marriage’ is described in Descent 2: 102–3.
In Descent 2: 106, CD remarked, ‘birds of the same sex, although not of course truly paired, sometimes live in pairs or in small parties, as is known to be the case with pigeons and partridges’. Hibernice: in Irish (Latin).
CD reported Fox’s information on polygamy among various domesticated birds in Descent 1: 270.
Fox refers to the black grouse (Tetrao tetrix).


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


Pairing habits of birds: polygamy among ducks and canaries.

Information on the proportion of sexes in fowls and other birds.

Letter details

Letter no.
William Darwin Fox
Charles Robert Darwin
Sent from
Source of text
DAR 86: A83–4
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5762,” accessed on 17 October 2021,

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