THE WORLD'S BIRDS. 65 



HUMMING-BIRDS (Trochilidce). 



DIAGNOSIS. Very small perching birds, with slender 

 bills and very short shanks. 



SIZE. From that of a swallow to that of a large humble- 

 bee. Some are the smallest of known birds. 



FORM. Bill always slender medium, long, or very 

 long, usually straight ; feet with very short shanks 

 and four free toes, three in front and one behind ; 

 wings narrow and generally long, with the arm 

 bones very short, most of the length being due to 

 the primary quills ; tail very varied in form ; head 

 large, neck long, body small but plump. 



Head and foot of Giant Humming-Bird (Patagonia gigas). 



PLUMAGE AND COLOURATION. Feathering close and 

 usually metallic, very commonly coloured green, 

 the lustre often very intense ; no seasonal change, 

 but often a sexual difference. Young like the female. 



YOUNG. Naked and helpless, with the bill short and 

 broad at first. 



EGGS. Two ; pure white. 



INCUBATION. Ten days, the hen only sitting. 



COURTSHIP. The male plays on the wing with expanded 

 tail. 



NEST. Suspended from a leaf or branch, to which it 

 is fastened by one side ; very neatly made of 

 plant-down, spiders' webs, etc., and small even for 

 the size of the birds. 



FOOD. Minute insects, etc., and nectar obtained from 



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