Why are rooks more sociable than ravens, and what do they gain from such communalism? These are favourite questions with persons informed with an intelligent passion for acquiring information, and the best answer, without any thought of irreverence, is "God knows!" It is most certain that we, at any rate, do not. So far from explaining how it was that rooks came to build their nests in company, we cannot even guess how the majority of birds came to build nests at all, instead of remaining satisfied with the simpler plan of laying their eggs in the ground that is still good enough for the petrels, penguins, kingfishers, and many other kinds. Protection of the eggs from rain, frost, and natural enemies suggests itself as the object of the nest, but the last only would to some extent be furthered by the gregarious habit, and even so we have no clue as to why it should be any more necessary for rooks than for crows. To quote, as some writers do, the numerical superiority of rooks over ravens as evidence of the benefits of communal nesting is to ignore the long hostility of shepherds towards the latter birds on which centuries of persecution have told irreparably. Rooks, on the other hand, though also regarded in some parts of these islands as suspects, have never been harassed to the same extent; and if anything in the nature of general warfare were to be inaugurated against them, the gregarious habit, so far from being a protection, would speedily and disastrously facilitate their extermination. Another curious habit noticed in these birds is that of flying on fine evenings to a considerable height and then swooping suddenly to earth, often on their backs. These antics, comparable to the drumming of snipe and roding of woodcock, are probably to be explained on the same basis of sexual emotion. The so-called parliament of the rooks probably owes much of its detail to the florid imagination of enthusiasts, always ready to exaggerate the wonders of Nature; but it also seems to have some existence in fact, and privileged observers have actually described the trial and punishment of individuals that have broken the laws of the commune. I never saw this procedure among rooks, but once watched something very similar among the famous dogs of Constantinople, which no longer exist.