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Darwin Correspondence Project

To Osbert Salvin   1 June 1868

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

June 1 1868

My dear Sir

I have thought that you wd forgive me for troubling you with some queries, & wd kindly answer them as far as you can. I have numbered my queries; & if you will return the paper your answers by reference to my numbers will be shortened.

But there is another point in which you can perhaps aid me. In your paper (Ibis Vol. 2.) you sometimes speak of having collected male Humming birds in certain relative proportions to the females; in other cases you speak of having collected so many actual male & female specimens. Now if your catalogue permits you without much trouble to tell me how many male & how many female specimens were collected in the case of the 7 species, mentioned by you, in which the males are in excess, I shd much like to know. Also I shd like to hear the actual number of male & female specimens in the 2 species in which the females were in excess.1

I unfortunately returned the Vol. of the Ibis & omitted to copy something which you said about the males killing each other. May I say that Mr S “has no doubt that the males frequently kill each other.”2 And now I will add my other queries.

Pray forgive me for being so troublesome & believe me My dear Sir | yours sincerely | Ch. Darwin

1 Is Trogon Mexicanus the same as Calurus resplendens, which de Saussure says makes a nest with a hole at each end?3 Do you believe this?

2. May I say that the males alone in Penelope & its sub-genera have the first or the 2 or 3 first primary wing feathers arched & attenuated, & in some species with part of the web cut out? I shall then give from Proc. Zoolog. Soc. your account of the noise thus made.4

3. Are the primary or secondary wing feathers of Selasphorus cut out? & is this structure confined to the males?5

4. In the pigeon Leptopila (is this spelt right?) is it the primary or secondary wing-feathers which are bowed & attenuated? Is this structure confined to the males? Is it actually known that these pigeons thus make any peculiar sound?6


CD cited Salvin’s ‘Notes on the humming-birds of Guatemala’ (Salvin 1860) in his remarks on the numerical proportions of the sexes in humming-birds in Descent 1: 307. CD’s summary of sex ratios drawn from Salvin 1860 is in DAR 86: C23.
See letter to the Linnean Society, 12 May [1868?]. Salvin described humming-birds fighting in Salvin 1860, pp. 261–2 and 270, but did not mention that they killed each other.
Trogon mexicanus is the mountain trogon. Calurus resplendens is the name given to the resplendent quetzal (Pharomachrus mocinno) in Swainson 1836–7, 2: 337–8; there is a lightly annotated copy of Swainson 1836–7 in the Darwin Library–CUL (see Marginalia 1: 795–6). In Saussure 1858–9, pp. 32–3, Henri Louis Frédéric de Saussure claimed that there was a nest of ‘Pharomacrus moccino’ at the Museum of Mexico with its entrance at the bottom, no doubt, he suggested, to allow the long tail of the male bird to hang down outside. There is a lightly annotated offprint of Saussure 1858–9 in the Darwin Pamphlet Collection–CUL.
CD cited Salvin’s remarks on the noise made by Penelope nigra (now Penelopina nigra, the highland guan: Birds of the world 2: 355) flying downwards in Descent 2: 64. Salvin’s remarks were in an article in the Proceedings of the Zoological Society of London for 1867; he argued that the genus Chamaepetes was closely allied with Aburria and some species of Penelope on the grounds that these differed from ‘true’ Penelope in having the three outer primaries strongly arched and attenuated (Salvin 1867, pp. 159–60). Penelope, Aburria, Chamaepetes, and Penelopina are all now assigned to the subfamily or tribe Penelopinae in the family Cracidae (Birds of the world 2: 311).
Salvin discussed the noise made in flight by Selasphorus platycercus (the broad-tailed humming-bird) in Salvin 1867, p. 160.
Although Salvin listed the genus Leptoptila (now Leptotila) in Salvin 1867, p. 159, he did not make any remarks on their feathers. Leptotila is the genus of white-tipped doves. Leptoptila is now considered an ‘incorrect subsequent spelling’ of Leptotila.


Birds of the world: Handbook of the birds of the world. By Josep del Hoyo et al. 17 vols. Barcelona: Lynx editions. 1991–2013.

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

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.

Salvin, Osbert. 1860. Notes on the humming-birds of Guatemala. Ibis 2: 259–72.

Salvin, Osbert. 1867. On some collections of birds from Veragua. [Read 24 January 1867.] Proceedings of the Zoological Society of London (1867): 129–61.

Saussure, Henri Louis Frédéric de. 1858–9. Observations sur les moeurs de divers oiseaux du Mexique. Bibliothèque Universelle et Revue Suisse. Archives des Sciences Physiques et Naturelles n.s. 1 (1858): 331–8; 3 (1858): 14–25, 168–82; 4 (1859): 22–41.

Swainson, William. 1836–7. On the natural history and classification of birds. 2 vols. London: Longman, Rees, Orme, Brown, Green, & Longman; John Taylor.


Encloses some queries.

Would also like information about proportion of male to female humming-birds.

Reference to OS’s paper in Ibis, vol. 2.

Letter details

Letter no.
Charles Robert Darwin
Osbert Salvin
Sent from
Source of text
Sybil Rampen (private collection)
Physical description
3pp encl 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 6221A,” accessed on 24 September 2021,

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