rather run, instead of hopping, their delicate little legs being often in such swift motion as hardly to be seen as they go; and all feed chiefly on insects — largely, I think, on minute beetles — and love our British streams and meadows for the never-failing abundance of food they find there. And I should add that in all our three birds the two outer tail-feathers are white, and become conspicuous the moment their owner flies or moves his tail in the familiar way: a characteristic of which I may have something to say later on.
These are the generic peculiarities of the group, and, as far as I know, they are common to all true Wagtails. But our three British species, though they are alike in so many ways, and are without doubt all descended from a single ancestral type, have developed features which mark them off very clearly from each other. The colouring, for example, is so distinct in the plumage of the adult male birds in breeding dress, as to be recognised at once even by the inexperienced; and it is interesting to find that they then represent three several types of the world's Wagtails. One is black and white, with a jet-black gorget; one is yellow and olive-brown, with no black at all; and the third, which stands between the two, though I take him last in this chapter, is gray above, bright yellow beneath, and has the same black throat ornament as his Pied cousin. Or to put it shortly,
