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Darwin Correspondence Project

From George Robert Gray   2 April 1868

B M.

2nd. April 1868

Dear Sir

I had the curiosity of enquiring from the keeper at the Gardens about the changes that take place in reference to the Scarlet Ibis.1 He says that the bird changes its plumage on the return of the breeding season. Yet on asking the same question of the Superintendent,2 he informed me, that the bird only changes once, that is from the brown plumage of the young state to the Scarlet of the mature bird; and that the only change that does take place on the return of the breeding season, is that the bill becomes black, instead of remaining of a reddish colour.3 I am now rather inclined to believe, that the Superintendent’s is likely to be the right one, as regard to the changes that do occur in the Scarlet Ibis, and, as it is in opposition to what I told you the other day, I therefore trouble you with this note4

I remain | Yours faithfully | G. R. Gray

C. Darwin Esqre.

CD annotations

1.4 that is … bird; 1.5] scored red crayon
Top of letter: ‘Ibis | G. R Gray,’ pencil; ‘very little’ red crayon


The scarlet ibis is now Eudocimus ruber. The keeper at the Zoological Gardens in Regent’s Park, London, has not been identified.
In Descent 2: 80, CD mentioned the change in beak colour in ibises, but did not cite Gray for the information.
CD’s notes indicate that he met Gray on 23 March 1868 (DAR 84.2: 209).


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


On the changes in plumage of scarlet ibis at the zoo in breeding season.

Letter details

Letter no.
George Robert Gray
Charles Robert Darwin
Sent from
British Museum
Source of text
DAR 84.1: 90–1
Physical description
ALS 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 6082,” accessed on 30 March 2023,

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