178 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
The variations in the ornamentation of the first primaries in the adults and 
the juvenals are seen in the picture, plate 2, fig. 1—38. 
The total length of the adults is in Cat. of birds said to attain as much as 
29 cm. In these specimens males and females are of different size, the females big- 
gest with a total length of 32 cm., the males 30 cm. Wing 21—22,6 cm. in the 
female, 20—22 cm. in the male. (About 20 cm. in the principal form, C. macrurus, 
according to Cat. of birds.) 
Moulting. — No specimen in real moulting, but in the juvenal !'"/s the two 
middle tail-feathers are growing out. These are gray (vermiculated in black). Pins 
in the grey of the nape and in the black of the crown too. That is also the case 
with the juvenal ”/s. And in specimen '!'/; (younger) there are pins in the grey. In 
this way these young specimens get the grey as a later stage (after the moulting) 
just in the same way as the bee-eaters (the two juvenals) got the black spot on the 
throat. 
Moultling-season. — The specimens that have been examined do not show 
what is the moulting-season, but it probably corresponds to that of other species: 
Jan., Febr., etc. 
Kceological. — The spotted night-jar was seen not infrequently at Meda, in the 
neighbourhood of Derby and at Sunday Island. 
On ”/, I found a nestling of this night-jar at the latter place. It lay close 
to a stone on the ground. The photograph shows its excellent protective position 
(Plate 4, fig. 5). The plumage is red-brown, spotted with grey, corresponding with 
the red-brown sandstone-rocks. The black wing-feathers were covered with the 
axillares. 
At several places I observed the flying game of the adult birds. Just after 
sunset the birds appeared. The night-jar always keeps on the ground, it flies up 
from there and falls down again on any bare sandy spot, on a distance of only 
about 10 m. from the spectator. ; 
The white tuft-like ruffles of the feathers in the neck and the white spots of 
the wing-feathers are of special interest. 'The white parts are hidden, when the bird 
is sitting on the ground, the tufts by the head and the two wing-spots by the red- 
brown tops of the big wing-coverts, which form a sort of cover to them. But when 
the bird is flying the white is singularly conspicuous. "This colour is also especially 
suited to be seen in the dark, which is the only time, when these birds are active. 
It is therefore evident that these white spots in a night bird have an ornamental 
purpose just for these flying games. These games remind one of those of Caprimulgus 
caprimulgus (L.). I did not, however, hear any spinning sound from the birds. 
