"The search after food,[143] as we agreed on a former occasion, is the principal cause why animals change their places. The different tribes of wading birds always migrate when rain is about to take place; and I remember once in Italy, having been long waiting, in the end of March, for the arrival of double snipe, in the campagna of Rome; a great flight appeared on the third of April, and the day after, heavy rain set in, which greatly interfered with my sport. The vulture, upon the same principle, follows armies; and I have no doubt that the augury of the ancients was a good deal founded upon the observation of the instinct of birds. There are many superstitions of the vulgar owing to the same source. For anglers, in spring, it is always unluckly to see single magpies; but two may always be regarded as a favourable omen; and the reason is, that in cold and stormy weather, one magpie alone leaves the nest in search of food, the other remaining sitting upon the eggs of the young ones: but, when two go out together, it is only when the weather is mild and warm, and favourable for fishing. "This reasoning will, in general, be found correct, and may be applied to solve many of the superstitions in the country; but the case of the magpie is entitled to a little more consideration. The piannet, as we call her in the North of England, is the most unlucky of all birds, to see singly at any time; this, however, does not often happen, except a short time during incubation; they either appear in pairs or in families; but even this last appearance is as alarming to our grandmothers. The following distich shows what each forbodes:--'One sorrow, two mirth, three a wedding, four death.' This bird, indeed, appears to have taken the same place with us, as an omen of evil, that the owl had amongst the ancients. The nurse is often heard to declare that she has lost all hopes of her charge when she has observed a piannet on the house-top.