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Darwin Correspondence Project

From Robert Swinhoe   14 April 1863

18 Royal Avenue Terrace | Chelsea

14 April, 1863.

My dear Sir,

A strong case in point for you is that of the Squacco Herons of the Old World, which you may or may not have in mind.1 It may not however have been brought before you before. It is the point of the various so-called species being almost identical in immature and winter dress, and yet perfectly distinct in their summer garb. The recognised species are the Ardeola comata, & of Africa and Southern Europe, the A. leucoptera, Boddaert of India, the A. speciosa. Horsf. of Java, and the A. prasinosceles, Swinhoe of China—2 Those in their summer dress are quite dissimilar, but almost indistinguishable in the plumage of the winter— There is however in Africa and South Europe a bird the A. ralloides, and in India and its archipelago another the A. malaccensis, which retains the immature or winter plumage with but little alteration all the summer through   The changes of plumage in this group due to whatever cause are worthy of record. I have mentioned them in my Formosan ornithology, which contains besides many other useful hints for you.3 I shall be sure to supply you with a copy of this paper, as soon as it is all printed off.4 I hope you will allow me to see you at your residence before I leave England.5 There is however as yet plenty of time, for I do not intend returning till September.

I remain, | Your’s very truly, | Robert Swinhoe

CD annotations

1.1 A strong … before. 1.3] crossed pencil
1.1 Squacco … Old] circled pencil & transposed to after ‘so-called species’ 1.3
1.3 you before.... point of] del pencil
1.3 the various] after opening square bracket, pencil
1.4 immature] underl pencil
1.4 winter] underl pencil
1.15 I hope … September. 1.17] crossed pencil
Top of letter: ‘On Sexual & immature dress, in Ardea’ ink; ‘This will work in well when I discuss the garb of young-Birds.’6 pencil


Swinhoe wrote to CD on 12 November 1862 and 2 December 1862 (see Correspondence vol. 10), but no intervening letters from CD have been found. CD discussed Squacco herons as an example of sexual selection in Descent 2: 190–2, citing Swinhoe (see n. 2, below).
Pieter Boddaert named Ardeola leucoptera, but the species classification for Ardeola was under contention (see Blyth 1849, p. 281 and Swinhoe 1863d, p. 421); Thomas Horsfield named A. speciosa in 1821 (see Mayr and Cottrell eds. 1979, p. 218). Swinhoe described A. prasinosceles, as well as other Squacco heron species, in Swinhoe 1863a, pp. 421–2. This paper was reprinted with different pagination (Swinhoe [1863d]) and circulated with a set of Swinhoe’s other 1863 publications (Swinhoe [1863b–g]; see letter from Robert Swinhoe, 29 July 1863 and n. 3). CD annotated the description of A. prasinosceles in his presentation copy of Swinhoe [1863b–g], which is in the Darwin Library–CUL (see Marginalia 1: 797). CD referred to Swinhoe’s information on Ardeola in Descent 2: 190.
See nn. 1 and 2, above. CD cited other information from Swinhoe [1863d] in Descent 2: 179, 190, 214–15.
Swinhoe [1863b]; see n. 2, above.
Swinhoe was British vice-consul in Formosa (now Taiwan) (P. B. Hall 1987). He had returned on leave to London in September 1862 (see Correspondence vol. 10, letter from Robert Swinhoe, 12 November 1862).
CD discussed the immature plumage of birds, including Ardea and other herons, in relation to the plumage of both sexes when adult in Descent 2: 182–223.


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.

Hall, Philip B. 1987. Robert Swinhoe (1836–1877), FRS, FZS, FRGS: a Victorian naturalist in Treaty Port China. Geographical Journal 153: 37–47.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.


Difference in plumage of Ardeola, a species of heron, in summer and winter. [See Descent 2: 190.]

Letter details

Letter no.
Robert Swinhoe
Charles Robert Darwin
Sent from
Source of text
DAR 84.1: 18–19
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 4094,” accessed on 13 August 2020,

Also published in The Correspondence of Charles Darwin, vol. 11