246 THE BIRDS OF AUSTRALIA 



upwards, the cloudless blue sky peopled at an immense elevation 

 by hundreds of these birds performing extensive curves and 

 sweeping flights, doubtless attracted thither by the insects that 

 soar aloft during serene weather. " It is fortunately frequently 

 out of reach of the most skilful "sportsman. ' ' These birds being 

 migrants from the Northern Hemisphere, arrive about 

 September and leave again in February. They breed 

 in China and Japan. Their nest is built of mud on 

 the side of some cleft on the face of a rocky cliff and 

 under cover, for instance near the Kegon Waterfalls in Japan, 

 where we saw many nesting in company with Cypselus pacificus. 

 These birds having such short legs and long wings cannot rise off 

 the ground; they therefore roost on the face of a cliff or rough 

 bark of a tree, but their home is the air, and they may some- 

 times be seen flying about on moonlight nights. Two elongated 

 white eggs are laid. 



Genus Cypselus. 

 Hind toe directed more or less forwards. 



The White-rumped Swift. 



Cypselus pacificus. 

 Nesting in Siberia, China, and Japan, migrates to Australia and 

 Tasmania in our summer. 



Brown above and below; back with bronzy lustre. Throat and rump 

 white. Feathers of under surface edged with white. Wings and tail dark 

 brown. Iris, bill and feet black. Wing to 7.3 inches. 



These birds usually both migrate and nest in company with 

 the Spine-tailed Swift. 



Order Coccyges. 

 Feet zygodactyle or semi-zygodactyle. 



Family Cuculidw. 

 Feet zygodactyle, two toes in front and two behind, as in the 

 Parrots. Oil gland nude. Tail feathers ten. Dorsal feather 

 tract furcate between the shoulders. Cosmopolitan. 



