Only one British gull, however, as far as I know, has taken up piracy as a profession, and that is the black-headed one. It is difficult in works of natural history to find any reference to this interesting fact, but it seems to be alluded to in one of the common or local names of this species, viz. the peewit-gull. For here the parasitic relation is between a sea-bird and a land-bird—the peewit, namely—which to me makes it still more interesting. At certain times of the year, and in certain parts of the country, almost every field or piece of land near the sea-shore in which peewits are feeding is sure to have a few of these gulls scattered about it. They stand, apparently, doing nothing, but are really keenly on the look-out, and as soon as a peewit has found anything, come sweeping down upon it. In the chase which ensues the pirate is not always successful, but very generally the peewit drops his booty, and the gull either catches it in the air or picks it up off the ground. In all the above kinds of robberies the young of the piratical species are fed more or less frequently with the food carried off by it from the various victims. This, however, is only incidental to the main habit, so that there is little in these bird doings to remind us of those horrid relations between insect and insect, with some examples of which this chapter opened, wherein one species is wholly sacrificed for the sake of the young of another. There is, however, a nearer approach to this—since though the effects are less tragic, the governing cause is the same—in that instinct which impels some few birds to lay their eggs in the nests of other species. Here, as the services of the foster parent are required, it does not itself suffer, but its own young perish to make place for the stranger. One most familiar example of this more advanced and complicated kind of parasitism is, of course, the cuckoo, but as the habits of this bird have been treated of in so many books, I need say nothing of them here. CHAPTER III PENGUINS AND THEIR WAYS—UNCROWNED KINGS AND EMPERORS—INNOCENT ARMIES—SURF MISSED IN A BASIN—DARWIN AND THE PENGUIN—HARANGUING THE PENGUINNERY.