From A. C. Smith 25 June 1873
Yatesbury Rectory | Calne | Wilts
June 25— 1873
Sir
I must apologize for the liberty I take in writing, to you; but I am so anxious to get your opinion on a point which nobody (I think) can answer so well as yourself, that I make bold to intrude upon you—. If I seem to be taking an unwarrantable liberty, it is because I am so well assured that none else to whom I can apply have such stores of facts to draw their inferences from as yourself
I seek information regarding the Cuckoo, and its propagation and my enquiry is, as to the possible amount of influence which a foster parent may have on the young entrusted to it.
It is (I think) conclusively proved that the Cuckoos egg frequently resembles the egg of the bird in whose nest it is laid; (the Germans say generally, but English Ornithologists deny this, so I prefer to say “frequently”) and the question is, how comes this variation of colouring?1
We may (I think) affirm, though this too has been questioned; that the Cuckoo herself who lays the Egg has no choice or will in the matter; but is quite unconscious (as all other birds are) of the colour of the egg she lays— Neither does it appear to be a provision of Nature, for securing the acceptance of the egg by the foster parents; for they are found to accept eggs of any colour.
What then can be the solution of this mystery? I have given much thought to it for years, and my present impression is (but it is no more than an impression until it is corroborated by better authority) that perhaps the nestling may imbibe with the food provided by its foster parents, some taint of that foster parents peculiarities: I know not how the pigment overspreads the egg of any bird, ere it leaves the ovary, or whence that pigment is supplied; but I fancy that every species of bird feeds its young after its own special manner; and probably the Hedge accentor, the titlark, and the Wagtail2 do not feed their young on precisely the same diet; Can it be then that diet affects the growing bird, and influences its after actions in any way?
I am well aware that in an analogous case the bees, when they have unexpectedly lost their queen, and no royal brood exists, can manufacture a queen out of a worker egg, by feeding the privileged grub with royal food.
Moreover it is a prevalent notion (though this may probably be a popular error,) that children imbibe from a wet nurse more or less of that nurses disposition!!
But I need say no more, except to ask you to excuse my thus troubling you: and if I can persuade you to give me a very few words in reply, I shall know whether to pursue or abandon my present notions on this particular.
In the event of your kindly answering my enquiry, would you also state if I am at liberty to use your name and authority on the points, as I have long been discussing this question in the Zoologist—;3 but I will of course (if you so desire it) not mention your name at all
Yours very sincerely | (Revd) A. C. Smith
Footnotes
Bibliography
Origin 6th ed.: The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 6th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1872.
Smith, Alfred Charles. 1868. On certain peculiarities in the life-history of the cuckoo, more especially with reference to the colouring of its eggs. Zoologist 2d ser. 3: 1105–18.
Summary
Wonders whether CD has any idea how the cuckoo manages to match its eggs to those of its host; believes it possible that the diet of the nestling cuckoo, which varies with its host, may affect its behaviour and the colour of its eggs.
Letter details
- Letter no.
- DCP-LETT-8950
- From
- Alfred Charles Smith
- To
- Charles Robert Darwin
- Sent from
- Calne
- Source of text
- DAR 177: 183
- Physical description
- ALS 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 8950,” accessed on 20 October 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-8950.xml
Also published in The Correspondence of Charles Darwin, vol. 21