Darwin, C. R. to Blyth, Edward
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Questions from CD related to bird plumage and sexual differences, with answers by EB.
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Transcription
Please return this paper
I have said in my M.S. on your authority, (but I suppose it is a blunder
on my part?) that the F. of Euplocomus has spurs. I see in Jerdon (III.
p. 541) that the F
[There are different types of Euplocamus (as admitted by Sclater). In
one of them, consisting of the ``small fire-back pheasants''
(Acomus), the females bear spurs, but not in the other types of that
group, as the ``great fire-backs,'' the Kallij-pheasants, the silver,
the Swinhoe's, and the Sha'n pheasants. Acomus comprises the
Phasianus erythropthalmus, Raffles, of Malacca and Sumatra; and a
``Duplicate race in Borneo. The ♀ of Galloperdix is spurless.]
In the Indian Field (1858. p. 52) you say that both sexes of Passer
castanopterus ``may be said to approximate in plumage to the female of
the common sparrow, with a spot of bright yellow on the breast & some
maronne at the shoulder of the wing.'' I also enclose an extract from
one of your letters on 2 other species of Passer:
Now will you consider whether I may say that the F. of the common
Sparrow is closely analogous in plumage to both sexes of any of the
above species.
[Yes. I think that you may fairly do so. But refer to the Ibis for April
1868, p. 205--6, with coloured figure published at the end of July No, &
you will find another remarkable instance in Petronia brachydactyla,
Tristram, of Palestine in which also the sexes are alike—clad in plumage
analogous to the ♀ of common sparrow.]
I see in Ibis vol. 6. p. 65 that the young Male of Petrocincla Cyanea
acquires some blue as a nestling. How are the adult & young Females
coloured? Is not this case analogous to that of Orocetes
erythrop:? And are not these birds allied?
[In habit, Orocetes is a forest thrush, Petrocincla (????'s
Petrocossyphus) a rock thrush; but as thrushes they are akin, & in
both groups the males are chiefly blue, the females brown; now, in the
first or nestling dress of the males, those feathers which are not
shed and renewed at the first moult, viz. the primaries and
rectrices, are blue-edged as in the adults in ♂,
brown-edged as in the adult in ♀—]
What does Swinhoe (Ibis. 1866 p. 296) mean by saying of the full
grown young of Urocissa Cerulea that they have ``a few of the occipital
feathers tipped with violet: Darwin again!''?
[Swinhoe evidently refers to the resemblance in this instance of the
occipital feathers of the young (or distinguished from the adult) of
Urocissa cærulea to what is seen in adults of U. sinensis, U.
occipitalis, and U. magnirostris—three very nearly allied races. In
the young of U. occipitalis (and probably of the others also) the
occipital pale colouring referred to is more developed in the young
than in the adult.]
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- f1 6532.f1
The date is established by the reference to the July 1868 issue of Ibis. - +
- f2 6532.f2
CD refers to the manuscript of the section on birds for Descent; he began writing this section on 17 May 1868 (see `Journal' (Correspondence vol. 16, Appendix II)). CD left a space after each question for Blyth's answers. Blyth's answers are reproduced here in square brackets. Blyth made some alterations to CD's text; he corrected CD's spelling of Euplocamus, the genus of small fireback pheasants. - +
- f3 6532.f3
Thomas Claverhill Jerdon wrote that females of the genus Galloperdix (spurfowls) had one or two spurs (Jerdon 1862--4, 2: 541). In Descent 2: 46, CD cited Jerdon, but wrote that females had only one spur. - +
- f4 6532.f4
Euplocamus (family Phasianidae) was the genus of gallopheasants, now replaced by the genus Lophura. For Philip Lutley Sclater's division of the genus into five sections, see Sclater 1863, pp. 118--21. - +
- f5 6532.f5
The `great fire-backs' included Euplocamus vieilloti ( now Lophura ignita rufa, Viellot's crested fireback), E. ignitus (now L. ignita ignita, the lesser Bornean crested fireback), E. nobilis (now L. ignita nobilis, the greater Bornean crested fireback), and E. swinhoii (Swinhoe's pheasant; now L. swinhoii). On Kalij pheasants, see the letter from Edward Blyth, [before 25 March 1868] and n. 16 (see also Sclater 1863, p. 121). The silver pheasant was E. nycthemerus (now L. nycthemera). Blyth was mistaken in including the Shan pheasant, which was not a species of Euplocamus; it was Phasianus amherstiae (now Chrysolophus amherstiae, Lady Amherst's pheasant). - +
- f6 6532.f6
Included in the section Acomus were Euplocamus erythrophthalmus (now Lophura erythrophthalma erythrophthalma, the Malayan crestless fireback pheasant), and E. pyronotus (now Lophura erythrophthalma pyronota, the Bornean crestless fireback pheasant). In Descent 2: 46, CD cited Blyth for information on spurs in females of E. erythrophthalmus. - +
- f7 6532.f7
Blyth deleted `castanopterus' and wrote `flavicollis' above. Passer castanopterus is the Somali sparrow; P. flavicollis is now P. pyrrhonotus (the Sind jungle sparrow). - +
- f8 6532.f8
[NEED TO FIND COPY OF the Indian Field ONLY ONE IN BL BUT SEEMS NOT TO HAVE ALL 1858. HAVE PUT IN BL QUERIES]. `Maronne' is evidently a reference to the colour maroon. - +
- f9 6532.f9
See letter from Edward Blyth, [before 25 March 1868] and n. 33. - +
- f10 6532.f10
Blyth refers to Tristram 1865--8, pp. 205--6. In the bound volume, the illustration of Petronia brachydactyla (the pale rock sparrow) is facing page 204. - +
- f11 6532.f11
CD refers to Wright 1864, p. 65, in which the author notes that male nestlings of Petrocincla cyanea (now Monticola solitarius, the blue rock thrush) can be distinguished by their blue wing-coverts. - +
- f12 6532.f12
Blyth crossed out `Erythrop' and wrote `erythrogaster' above it. Orocetes erythrogaster is now Monticola cinclorhynchus (the blue-capped rock thrush). - +
- f13 6532.f13
In Descent 2: 219--20, CD discussed plumage differences in these thrushes and cited the information from Wright 1864, p. 65. Blyth used an upside-down female symbol instead of a male symbol here. - +
- f14 6532.f14
CD quotes from Robert Swinhoe's description of Urocissa caerulea (the Formosan magpie) in Swinhoe 1866, pp. 296--7. - +
- f15 6532.f15
Urocissa sinensis is now U. erythrorhyncha (the blue magpie); U. occipitalis and U. magnirostris are now considered subspecies of U. erythrorhyncha. - +
- f16 6532.f16
The page reference is presumably to CD's manuscript (see n. 1, above).