My Dear Sir

I thank you very much for the kind manner in which you were pleased to speak of my contribution on Apterous Lepidoptera.—²

My Brother Harrison³ & myself have always from our boyhood kept numbers of living creatures, he has however been more of a fancier, & I have been more of a naturalist, I may say that the love of the Science is with me a passion

I trust my paper shewed that I am thoroughly a disciple of yours, but if it did not let there be no doubt on the point.—

Not being a Systematist I have time for observations & will endeavour to aid you to the best of my power.—

I cannot at present reply very definitely to any of your questions, but a few remarks bearing on sexuality may not be out of place.

Birds undoubtedly distinguish colors.— I had a Green Linnet in my aviary & at that time no other bird approaching it in color, when I introduced a Yellow Hammer ♂ it at once placed itself by its side & was the only companionable bird to the new arrival, soon afterwards a Canary ♀ was placed in the aviary   it immediately flew towards it and would not move from its side, but did not exhibit any sexual desire—⁴

A few days since I was obliged to release a Robin because it began to close the eyes of all birds with red on their plumage   it caused the death of a red breasted Crossbill & nearly killed a Goldfinch.⁵ No other bird appeared to be molested except when feeding, all birds however generally quarrel over a meal.—

Amadina Castanotis from Australia bred twice in my aviary, & I had the opportunity of observing the use of the particolored feathers of the tail, these when love making were slightly spread and vibrated in a most peculiar manner, unlike any other bird.—

The nearly allied Amadina Lathami had very different antics shewing its brilliantly spotted breast & exhibiting, the bright crimson patch just over the tail⁶

There was nothing particularly striking in the Weavers (Textor Erythrorynchus)⁷ but in addition to the changes of plumage in these birds in the male sex, there was a singular change of color in the beaks of the females, during the winter the beaks of both ♂ & ♀ were bright red & the plumage of the sexes exactly alike, in the Summer the ♂ put on his nuptial plumes & his beak became redder but the females losing color became almost a light yellow.—

The Vidua Erythrorynchus⁸ perhaps the bird adverted to by you I have had, its pugnacity when the long feathers are produced is extreme & in common with other birds in confinement it dies of apoplexy, & I find the greatest practical difficulty in making experiments which even produce the most meagre results.—

I find that birds recognize near species, for instance, the Redpole Linaria minor is a very affectionate little bird and often feeds its companions without distinction of sex, “Linaria borealis” was fed by “minor” in the same manner, sometimes “Linaria montana” (The Twite) received the same attentions, and when there ⁠⟨⁠w⁠⟩⁠ere no “Linariæ” to feed the “Siskin” (Carduelis spinus) was treated with the same affectionate attentions.—⁹

I fear you will be now quite tired of reading such unsatisfactory observations.—

I have a few remarks to make on the color of Butterflies which I will send in a few days.—

Yours very faithfully | J Jenner Weir

C Darwin Esq^r. | Down