144 THE WORLD'S BIRDS. 



and are so on some Argentine estancias, by driving 

 in and plucking the birds. Clipping would, of 

 course, be better. The flesh is good eating, some- 

 thing between mutton and turkey, and the gizzards 

 have been used for the preparation of pepsin. 



CAPTIVITY. Rheas do well in captivity, both in hot 

 and temperate climates. They breed regularly in 

 European parks. 



DISTRIBUTION AND SPECIES. South America only, in 

 open grassy country. There are only two species, 

 the Common Rhea (Rhea americana), larger, with 

 grey plumage, black on the crown and at the base 

 of the neck, which lays creamy- white eggs ; and 

 Darwin's Rhea (Rhea darwinii], smaller, brown, 

 spotted with white, and laying pale green eggs. 

 This is confined to Patagonia. Both species are 

 locally known as ostriches. 



ROLLERS (Coraciida). 



DIAGNOSIS. Tree birds of medium size, with crow-like 

 bills and feet with four free toes, the hind-toe 

 smallest. 



FORM. Bill medium, strong, crow-like, corner of 

 mouth below eye ; feet with shanks medium or 

 short, toes four, all free, hind-toe smallest ; wings 

 short to long ; tail medium to long ; head large, 

 body light. 



PLUMAGE AND COLOURATION. Feathers close and 

 beautifully coloured, blue, purple, green and 

 lilac being common tints. No sexual difference, 

 as a rule, nor seasonal change, but young are not 

 always like parents. 



YOUNG. Naked and helpless, fed by parents. 



EGGS. Several ; pure white. 



INCUBATION. About three weeks 



