To the Editor of the Echo.

     Sir,--Your correspondent, Mr. George Rooper, who severely criticises what he supposes to be my views in your paper of the 8th inst., is so evidently well acquainted with the habit of birds that I regret he did not take the trouble to read my book before he took up his pen to write on the subject. A criticism at second-hand is hardly likely to be a just one.

     I am, however, always pleased to be criticised by one who has practical knowledge, however much he may misunderstand me, and as Mr. Rooper adduces some interesting facts which seem to me strongly to corroborate my theory, I will, with your permission, make a few remarks on his letter.

     Mr. R. asserts that "my first axiom that birds build with the materials readiest at hand, is absolutely contrary to fact; birds invariably seek the materials of their nest at a distance." At a distance from what? I would ask. Not surely at a distance from the places they frequent daily in their search for food, though it may be at a distance from the nest; and the former, not the latter, is my axiom. Take the case of the rooks. They are great wanderers, going miles away during the day, but returning to the rookery at night. They spread themselves over the country to seek food, for the simple reason that the whole population of a rookery could not live a week if confined to the immediately adjacent fields, and neither could all find materials for their nests so quickly and so easily in the trees they inhabit as in the wide extent of country they daily frequent.

     The fact of the grebe bringing up bits of weed from the bottom to make its nest is new to me, and is very interesting, since it exactly accords with my theory. For is not the grebe pre-eminently a diver? Does it not live by diving, and bring all its food out of the water; and is not the fact that it also brings weed for its nest out of the water instead of from its surface, strikingly accordant with the view, that birds use those materials for their nests that come most directly in their way during their daily search for food.

     As for the water-ouzel bringing dry oak leaves home from "incredible distances," the fact, of which Mr. R. gives no proof, seems to me incredible; because, in Wales and Devonshire, where the bird abounds, oaks are one of the commonest trees, and grow, more or less plentifully, on the banks of most streams.

     Mr. R. denies that the kingfisher makes a nest at all, and says that the supposed nest is merely the dirty bird's dunghill. But Mr. Gould has himself obtained a perfect hollow nest, formed of fish-bones, so delicately white and so beautifully put together, as to be quite an ornamental object. If Mr. R. will call and see this nest, I think he will withdraw his accusation against the poor kingfisher.

     Mr. R. also denies that birds alter and improve their nests as occasion requires, but I have stated many facts which prove the contrary; and quite recently M. Pouchet has shown that the common swallow has, during the last forty years, materially altered its mode of nest-building at Rouen, and that the alterations are decided improvements. An account of M. Pouchet's observations is given in Nature for April 7th last.

     The close similarity of nests of the same species of bird at the present day is admitted, but is nothing to the purpose, since my statement is, that changes occur slowly in relation to changed conditions of the bird itself, or its surroundings. Unfortunately we have no nests of prehistoric or fossil birds, and can therefore only determine the question by reason and analogy.

     Though the nests of the wren, the robin, or the nightingale may be rough externally, or of apparently loose and flimsy texture, yet they are smooth and regular within, and are so well constructed that the materials cling together and form a compact and tolerably strong abode for the young birds. It is certain, therefore, that they cannot be put together in the "careless, unmethodical manner" Mr. R. thinks they are, but must be, to some extent, formed like a woven fabric, implying both activity and delicacy in the bills and feet of the builders.

     These, and many more of Mr. Rooper's objections, are sufficiently answered in my volume of Essays, where he will see that the fact of the female redbreast being conspicuously coloured, is perfectly consistent with my theory, since the colour is hidden while she is sitting on the nest, while the hen goldfinch is certainly less vividly coloured and less conspicuous than the cock birds.

Alfred R. Wallace.
Holly House, Barking, E.