I need not dwell upon the associations of male and female for rearing their offspring, for providing it with food during their first steps in life, or for hunting in common; though it may be mentioned by the way that such associations are the rule even with the least sociable carnivores and rapacious birds; and that they derive a special interest from being the field upon which tenderer feelings develop even amidst otherwise most cruel animals.  It may also be added that the rarity of associations larger than that of the family among the carnivores and the birds of prey, though mostly being the result of their very modes of feeding, can also be explained to some extent as a consequence of the change produced in the animal world by the rapid increase of mankind.  At any rate it is worthy of note that there are species living a quite isolated life in densely-inhabited regions, while the same species, or their nearest congeners, are gregarious in uninhabited countries.  Wolves, foxes, and several birds of prey may be quoted as instances in point.

However, associations which do not extend beyond the family bonds are of relatively small importance in our case, the more so as we know numbers of associations for more general purposes, such as hunting, mutual protection, and even simple enjoyment of life.  Audubon already mentioned that eagles occasionally associate for hunting, and his description of the two bald eagles, male and female, hunting on the Mississippi, is well known for its graphic powers.  But one of the most conclusive observations of the kind belongs to Syevertsoff.  Whilst studying the fauna of the Russian Steppes, he once saw an eagle belonging to an altogether gregarious species (the white-tailed eagle, Haliactos albicilla) rising high in the air for half an hour it was describing its wide circles in silence when at once its piercing voice was heard.  Its cry was soon answered by another eagle which approached it, and was followed by a third, a fourth, and so on, till nine or ten eagles came together and soon disappeared.  In the afternoon, Syevertsoff went to the place whereto he saw the eagles flying; concealed by one of the undulations of the Steppe, he approached them, and discovered that they had gathered around the corpse of a horse.  The old ones, which, as a rule, begin the meal first—­such are their rules of propriety-already were sitting upon the haystacks of the neighbourhood and kept watch, while the younger ones were continuing the meal, surrounded by bands of crows.  From this and like observations, Syevertsoff concluded that the white-tailed eagles combine for hunting; when they all have risen to a great height they are enabled, if they are ten, to survey an area of at least twenty-five miles square; and as soon as any one has discovered something, he warns the others.(11) Of course, it might be argued that a simple instinctive cry of the first eagle, or even its movements, would have had the same effect of bringing several