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Darwin Correspondence Project

To A. D. Bartlett   16 February [1868]1

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

Feb. 16th

My dear Sir

I want to beg two favours of you.— I wish to ascertain whether the Bower-Bird discriminates colours. Will you have all the coloured worsted removed from cage & the bower, & then put, all in a row, at same distance from bower, the enclosed coloured worsted, & mark whether the Bird at first makes any selection.2 Each packet contains equal quantity; the packets had better be separated & each thread put separate, but close together; perhaps it would be fairest, if the several colours were put alternately,—one thread of bright scarlet, one thread of brown, &c &c. There are six colours.— Will you have kindness to tell me whether the birds prefer one colour to another?

Secondly, I very much want several heads of the fancy & long-domesticated rabbits to measure the capacity of skull. I want only small kinds; such as Himalaya, small Angora, Silver Grey or any small-sized rabbit which has long been domesticated. The Silver-Grey from warrens would be of little use. The animals must be adult. & the smaller the breed the better.3

Now when any one dies would you send me the carcase named ; if the skin is of any value it might be skinned; but it would be rather better with skin & I could make present to any keeper to whom the skin is perquisite.

This would be great assistance to me, if you would have kindness thus to aid me.

My dear Sir | Yours sincerely | Ch. Darwin

Address for dead Rabbits

Ch. Darwin Esqre care of Down Postman Bromley | Kent | per Rail


The year is established by the relationship between this letter and the letter from A. D. Bartlett, 9 December 1867 (Correspondence vol. 15, and by its connection with CD’s research in 1868 on the perception of colour in birds (see n. 2, below).
Though Bartlett wrote that he would try the experiment with the bowerbird (Chlamydera) in his letter of 9 December 1867, no further correspondence on the subject has been found, and CD does not provide results of the experiment in his discussion of the bowerbird’s ‘taste for the beautiful’ in Descent 2: 112–13. See also Descent 1: 63, and 2: 69–71. CD’s ideas regarding beauty, sexual plumage of birds, and natural selection, had recently been challenged by George Douglas Campbell, the duke of Argyll (see Correspondence vols. 14 and 15). For more on CD’s interest in colour discrimination in birds, see Correspondence vol. 16, letter to J. J. Weir, 27 February [1868].
CD had attended to the osteology of different breeds of rabbits from 1855 to 1865, particularly in 1856 and 1861 when he had skeletonised different rabbits (see, for example, Correspondence vol. 6, letter to W. D. Fox, 8 [June 1856], and Correspondence vol. 9, letter to W. B. Tegetmeier, 22 March [1861]); he usually asked that the skull be preserved when the rabbit was killed. See Variation 1: 124–9 for CD’s discussion of the brain capacity of domestic rabbits, and the table in ibid., p. 127 for a comparison of skull length and capacity in wild, feral (Porto Santo), and domestic rabbits, including the Himalayan, Angora, and a silver-grey from a warren. CD wanted small specimens of domestic rabbits for comparison with wild rabbits because the former tended to be larger. Two years earlier, CD had asked Bartlett for the body of one of his Porto Santo rabbits, with the skull undamaged (Correspondence vol. 13, letter to A. D. Bartlett, 30 January [1865]). There is no further extant correspondence on rabbit skulls; however, CD included remarks about the modification of the skull and brain size of rabbits in the course of domestication in Descent 1: 147–8.


Asks ADB to perform experiment on colour perception in bower-bird.

Asks for rabbit specimens.

Letter details

Letter no.
Charles Robert Darwin
Abraham Dee Bartlett
Sent from
London, Queen Anne St, 6 Down letterhead
Source of text
Wellcome Library (Wellcome Western MS. 7781/7)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5401,” accessed on 16 July 2019,

Also published in The Correspondence of Charles Darwin, vol. 18 (Supplement)