ON THE “HUMMING” OF THE SNIPE. 125 
one which will make so loud and so good an imitation of the 
Snipe’s “humming.” But any of the primary wing-feathers will 
give forth a faint sound, which may be increased in proportion to 
the number of them passed through the air at once. 
Again, it does not appear to me clear that the position of a 
tail-feather at the end of a long switch when drawn through the 
air is identical with the position which it would occupy in the 
tail of the bird when flying downwards. On the contrary, it 
would seem that the reason why the tail-feather emits a sound 
at the end of a switch is because it is drawn through the air, 
in a position which is occupied naturally by the primaries, but 
unnaturally by the tail, and hence that it must be the primaries 
(collectively) which produce the sound in nature. In this our 
sense of hearing is assisted by the sense of sight, for a perceptible 
vibration of the quill-feathers is observed every time the bird 
descends. 
In the case of Peewits, Rooks, and other birds, it may be said 
that the sound which they produce in falling through the air is 
by no means identical with that produced by the Snipe. True; 
but it is an analogous sound, and the fact that they are able, with 
very different tail-feathers, to make a sound of this nature at all, 
seems in itself a strong argument against the tail-feather being 
the agent in producing it. 
In offering these remarks for the consideration of naturalists, 
it must not be supposed that I wish to disparage in any way the 
extremely ingenious theory of Herr Meves, which has met with 
the approval of many ornithologists: at the same time it may be 
observed that this theory is by no means universally accepted, and 
in expressing my own adherence to the “theory of the wings” I am 
supported by the opinion of many excellent field-naturalists. 
The late Sir William Jardine wrote :*—* The sound is never 
heard except in the downward flight, and when the wings are in 
rapid and quivering motion; their resistance to the air, without 
doubt, causes the noise which forms one of those agreeable 
variations in a country walk, so earnestly watched for by the 
practical ornithologist.” 
Mr. John Hancock, in his ‘ Catalogue of the Birds of North- 
umberland and Durham’ (1874), devotes several pages (pp. 106— 
113) to a consideration of this question, and gives his entire 
* *The Naturalists’ Library’ (Ornithology), vol. xxvi., p. 180, 
