Saras Cranes, which strike wickedly and without warning; Some Herons, especially if confined, and Birds of Paradise, which are unreasonably quarrelsome. 6. In non-social birds, each male will fight for his own breeding and feeding territory. The struggle for territory is a wide one, and it is now attracting the attention of bird psychologists. Birds are no more angelic than human beings are. They have their faults and their mean traits, just as we have; but their repertoire is not so great as ours. In every species that we have seen tried out in captivity, the baser passions are present. This is equally true of mammals. In _confinement_, in every herd and in every flock from elephants down to doves, the strong bully and oppress the weak, and drive them to the wall. _The most philosophic and companionable birds_ are the parrots, parakeets, macaws and cockatoos. _The birds that most quickly recognize protection_ sanctuaries and accept them, are the geese, ducks and swans. _The game birds most nervous and foolish, and difficult to maintain in captivity,_ are the grouse, ptarmigan and quail. _The bird utterly destitute of sense_ in captivity is the loon. _The birds that are most domineering_ in captivity are the cranes. _The birds that are most treacherous_ in captivity are the darters (_Anhinga_). _The birds that go easiest and farthest in training_ are the parrots, macaws and cockatoos. _The most beautiful bird species of the world_ are about fifty in number; and only a few of them are found among the birds of paradise. The minds of wild birds are quite as varied and diversified as are the forms and habits of the different orders and genera. XVI THE WISDOM OF THE SERPENT OF all the vertebrates, the serpents live under the greatest handicaps. They are hated and destroyed by all men, they can neither run nor fly far away, and they subsist under maximum difficulties. Those of the temperate zone are ill fitted to withstand the rigors of winter. And yet the serpents survive; and we have not heard of any species having become extinct during our own times. It is indeed worth while to "consider the wisdom of the serpent." Without the exercise of keen intelligence all the snakes of the cultivated lands of the world long ago would have been exterminated. The success of serpents of all species in meeting new conditions and maintaining their existence in the face of enormous difficulties compels us, as reasoning beings, to accord to them keen intelligence and ratiocination.