I can make no answer with respect to the elephants. With respect to the female reindeer, I have hitherto looked at the horns simply as the consequence of inheritance not having been limited by sex. Your idea about colour being concentrated in the smaller males seems good, and I presume that you will not object to my giving it as your suggestion. LETTER 444. TO J. JENNER WEIR. Down, May 7th [1868]. I have now to thank you for no less than four letters! You are so kind that I will not apologise for the trouble I cause you; but it has lately occurred to me that you ought to publish a paper or book on the habits of the birds which you have so carefully observed. But should you do this, I do not think that my giving some of the facts for a special object would much injure the novelty of your work. There is such a multitude of points in these last letters that I hardly know what to touch upon. Thanks about the instinct of nidification, and for your answers on many points. I am glad to hear reports about the ferocious female bullfinch. I hope you will have another try in colouring males. I have now finished lepidoptera, and have used your facts about caterpillars, and as a caution the case of the yellow-underwings. I have now begun on fishes, and by comparing different classes of facts my views are getting a little more decided. In about a fortnight or three weeks I shall come to birds, and then I dare say that I shall be extra troublesome. I will now enclose a few queries for the mere chance of your being able to answer some of them, and I think it will save you trouble if I write them on a separate slip, and then you can sometimes answer by a mere "no" or "yes." Your last letter on male pigeons and linnets has interested me much, for the precise facts which you have given me on display are of the utmost value for my work. I have written to Mr. Bartlett on Gallinaceae, but I dare say I shall not get an answer. I had heard before, but am glad to have confirmation about the ruffs being the most numerous. I am greatly obliged to your brother for sending out circulars. I have not heard from him as yet. I want to ask him whether he has ever observed when several male pigeons are courting one female that the latter decides with which male she will pair. The story about the black mark on the lambs must be a hoax. The inaccuracy of many persons is wonderful. I should like to tell you a story, but it is too long, about beans growing on the wrong side of the pod during certain years. Queries: Does any female bird regularly sing? Do you know any case of both sexes, more especially of the female, [being] more brightly coloured whilst young than when come to maturity and fit to breed? An imaginary instance would be if the female kingfisher (or male) became dull coloured when adult.