The food habits of cuckoos render them very desirable, since they eat hairy caterpillars, particularly tent-caterpillars, for which they seem to have an especial fondness, fall web-worms and locusts, besides other injurious insects, but they are accused of bad habits in relation to other birds, and can therefore hardly be classed among the wholly useful birds. Warblers and vireos are among the most helpful birds in an orchard, devouring large quantities of insects. There is no class of birds concerning which it is more necessary that the farmer should be well informed, than the hawks and owls, since some of them are wholly good, and of the greatest possible benefit to him and the fruit grower, while others are extremely harmful in their food habits. The harmful varieties live almost entirely on poultry and wild birds, and include the goshawk or partridge hawk and the Cooper hawk, which is a true chicken-hawk and should be recognized by all farmers at sight. The goshawk and chicken-hawk, in the amount of damage done, far exceed all other birds of prey. The sharp-shinned hawk rarely attacks full-grown poultry, but preys heavily on young chickens and song birds. In fact, it is known to eat nearly fifty species of our most useful birds. There is no question that these birds are a serious pest and should be destroyed, but they should not be confused with other members of the family which are among the best friends that a farmer has in keeping his farm clear of small enemies. Owls and hawks eat the same class of food, the hawks flying by day and the owls by night. Owls remain North in winter, while hawks fly farther south. The small species of both eat large quantities of insects, such as grasshoppers, locusts and beetles. The larger ones are the farmer's great protection against the meadow-mouse, the most destructive of all animals to farm crops. It tunnels under fields and eats the roots of grass, grain and potatoes, eats large amounts of grain and does even more damage by girdling young trees in orchards. Rabbits injure trees in the same way, often during the winter ruining an entire orchard in this manner. Squirrels, ground-squirrels, gophers, prairie-dogs, and other small animals do serious damage in the course of a year on almost every farm. The rough-leg hawk feeds entirely on meadow-mice, but if the supply fails, it eats mice, rabbits and ground-squirrels, but in no instance attacks birds. Its cousin, the ferruginous rough-leg, lives largely on ground-squirrels, rabbits, prairie-dogs and pouched gophers. This species also never attacks birds, and neither do any of the four members of the kite family.