On polygamous birds and the pairing of birds. Late singing of males. [see Descent 2: 107.]
Darlington Place | Bath
Feb. 27— /68
My dear Darwin,
I was pleased to have your letter, it being so very long since I heard any thing of you direct from yourself;— since we last met it is positively more than twenty years!
I hope you have not thought me long in answering, but I was
rather busy when it came;—also, having attended but very
little to Zoology since I left Camb
That the pheasant is really polygamous, I sh
Possibly with some species of birds,—whether they are
polygamous or monogamous may depend upon the circumstances under
I am not sure that I quite see the drift of your remark, that
you ``suppose such birds as blackbirds & bullfinches, in which
the sexes differ in colour, pair strictly'';— it would
seem as if you considered there was a connection between
pairing & such difference of plumage in the two sexes;—yet in
the Raven, w
With regard to your last question, I conceive it is very
difficult to estimate the relative numbers of the two sexes in
any species of bird, at least during the breeding season or to
say which sex preponderates.— It is a remarkable, tho'
well-known circumstance,—that in the breeding-season, when
birds that strictly pair might be supposed in pairs,—(i.e.
if the sexes are in equal proportion)—if one sex be killed the
other generally finds a second mate to take its place—and
quickly too;— I remember having read somewhere, but I
cannot put my hand upon the place, of a gentleman who, in the case of a
pair of magpies that had built near his house, shot one of the
sexes (I forget which) seven times in succession, the place of
the one killed having been supplied as often as that, before
there was a stop put to it.— That birds sometimes, under such circumstances, have a
difficulty in procuring another mate, or are unable, I gather
from cases in which the song of the male is protracted very much
beyond the usual time, as in that of the nightingale mentioned by
me—p. 88 of ``Observ
Might it not be possible, in the case you put—of females
being in excess over the males—that a cock blackbird or
Or, without any disproportion in the sexes, there might be a disproportion in the numbers sufficiently matured for nidification, by reason of the young of the previous year having been hatched some very much earlier than others,— amongst these might be a few which would just breed or not according as they were able or not to get mates late in the spring or summer, when the great bulk had been served, but they themselves were not ready sooner.— I merely throw out these crude suggestions as contingencies—which possibly may arise & help to explain some of the apparent anomalies, or difficulties, connected with the subject on which you write. But cast them at once aside, if not worth attending to.— My letter is long enough, & it is time to stop.
I am very glad to find you speaking of yourself as so much better in health than formerly. I sincerely hope you may be able to continue your labours, & bring them, without check or hindrance, to whatever end you set before you as the goal to be reached ultimately if possible.— I have just got your last work on the variation of domestic animals & plants,—which I shall look at with great interest.— I am in tolerable health myself, though not very strong,—& unequal to much work at a time either of body or mind.— I am not a quarter so industrious as yourself. Of late years I have amused myself chiefly with our British plants, & during last season,—as well as at this present time,—especially with the Mosses.
But I take great interest in our Field Club, founded by myself—some 13 or 14 years ago,—& flourishing well, as regards both numbers & work done,—tho' I am not strong enough to join it in its excursions.— I am also just now very busy in getting together a Local museum in the building of the Bath Lit. & Scient. Institution.—
It will never, however, be anything approaching to the admirable museum got up by Henslow at Ipswich.—
Believe me, | My dear Darwin, | Your's very Sincerely | L. Jenyns.
P.S. I have only just by accident caught sight of your question
at the end relating to the horns in the males of the Lamellicorn
- f1 5944.f1See letter to Leonard Jenyns, 22 February  and n. 2. The last known meeting between Jenyns and CD was in Southampton at the meeting of the British Association for the Advancement of Science in 1846 (Correspondence vol. 3, letter to J. S. Henslow, [5 October 1846]).
- f2 5944.f2Jenyns had been vicar of Swaffham Bulbeck, Cambridgeshire, until 1849. Jenyns and CD became friends while CD was at Cambridge (see Correspondence vol. 1 and I. Wallace ed. 2005, p. 68).
- f3 5944.f3Jenyns refers to Ornithological dictionary (Montagu 1802, 1: s.v. Grous-Wood, Grous-Black, Grous-Red), and to Illustrations of British ornithology (Selby 1833, 1: 424, 428). CD cited George Montagu and Prideaux John Selby on the black grouse (Tetrao tetrix) and red grouse (now Lagopus lagopus scotica) in Descent 1: 269 n. 8. The red grouse was then Tetrao scoticus (see Descent 2: 170).
- f4 5944.f4Montagu 1802, 2: s.v. Pheasant-Common.
- f5 5944.f5Bottisham Hall in Cambridgeshire was the Jenyns family residence (I. Wallace ed. 2005, p. 15).
- f6 5944.f6The reference is to Yarrell 1843--56, 2: 312.
- f7 5944.f7Montagu 1802, 1: s.v. Cuckow-Common, Duck-Common, or Wild.
- f8 5944.f8CD remarked in Descent 1: 266 that although some relation existed between polygamy and the development of secondary sexual characters, many animals, especially birds, that were monogamous, displayed strongly marked secondary sexual characters, while some few animals, which were polygamous, were not so characterised.
- f9 5944.f9On the nesting habits of magpies, see also the letter to W. D. Fox, 25 February  and n. 2.
- f10 5944.f10CD cited Jenyns's Observations in natural history (Jenyns 1846) on various male birds singing after the mating period in Descent 2: 107 n. 7.
- f11 5944.f11Jenyns refers to Variation.
- f12 5944.f12Jenyns had founded the Bath Natural History and Antiquarian Field Club in 1855 (see I. Wallace ed. 2005, pp. 24, 95). On Jenyns's connection with the Bath Royal Literary and Scientific Institution and its museum, see ibid., pp. 23--5, 31.
- f13 5944.f13On John Stevens Henslow's involvement with the Ipswich museum, see S. M. Walters and Stow 2001, pp. 221--8.
- f14 5944.f14See letter to Leonard Jenyns, 22 February .