THE WORLD'S BIRDS. 21 



fed by the foster-parents, and often eject the young 

 of these. 



NEST. In non-parasitic forms rather rough, composed 

 of sticks, coarse grass, etc. ; in some cases open, 

 in others domed. 



EGGS. Several ; varying in colour. In parasitic forms 

 they often resemble those of the host, and are 

 often spotted ; in non-parasitic forms plain white 

 or blue is the rule. 



INCUBATION. About a fortnight, in the common 

 European Cuckoo. 



FOOD. Chiefly insects, or other small animals a few 

 feed chiefly or partially on fruit. They are re- 

 markable for being able to devour what other 

 birds usually refuse, such as hairy caterpillars and 

 toads. 



GAIT. In the short-legged tree-haunting forms an 

 awkward hop ; in the strong-legged running kinds 

 an active walk or run. All perch freely. 



FLIGHT. In the long-winged tree-haunting kinds swift 

 and elegant, with rapid action of the wings ; these 

 often catch prey on the wing. In the short-winged 

 kinds slow, heavy, and low, and not continued 

 far. The feet are extended behind in flight. 



NOTE. Generally peculiar and characteristic, and 

 often articulate in character, varying much in 

 different species. Our bird is the only one which 

 cries " cuckoo " ; several have notes running up 

 the scale. 



DISPOSITION AND HABITS. Cuckoos are usually greedy 

 and unsocial birds, but probably have a good deal 

 of intelligence ; they are easily tamed. 



ECONOMIC QUALITIES. Their destruction of injurious 

 insects, etc., makes them some of the most valuable 

 and important of birds. 



CAPTIVITY. Only one species, the fruit-eating Koel 

 (Eudynamis honorata),is commonly kept, and that 



