NIGHTJARS. 
45 
also a genus ( Scotornis ) which has an 
elongated tail, longer than the body 
of the bird itself, the feathers gradually 
decreasing in length till the outside 
ones are the shortest. In South 
America, the genus under consider¬ 
ation has the outer tail-feathers pro¬ 
duced, and the two central ones also, 
the next pair being the shortest. In 
Macropsalis, however, the outside pair 
of tail-feathers are produced to an 
enormous length and form a train, 
the feathers gradually reduced in size 
towards the middle of the tail, the 
two centre ones being the shortest. 
Of the Argentine fork-tailed nightjar 
(Hydropsalis furcifera), Durnford 
states that it is not uncommon near 
Buenos Aires in spring and autumn, 
living on the ground in damp situa¬ 
tions where the grass is long and thick 
enough to afford some slight cover, 
and is generally observed in parties of 
four or five individuals. Its flight is 
noiseless, and performed by jerky, 
erratic movements. In Entre Bios, 
Mr. J. B. Barrows found it common in 
summer, arriving in August and leaving 
in May; and he states that “ while 
hunting capivaras and armadillos by 
moonlight, I had frequently good 
opportunities for watching its move¬ 
ments. Its flight is nearly as irregular 
and as noiseless as that of a butterfly, 
while its beautiful tail is opened and 
shut in the same manner as with the 
scissor - tailed flycatcher. Alighting 
frequently on the ground, or on stones 
or roots, it keeps up a continual but 
very soft clucking, which is the only 
note uttered. It was most often seen 
in open grassy or sandy spots in the 
woods, especially along the margins of 
the streams. By day it sits close on 
the ground, and, if disturbed, only flies 
a few yards, though it evidently sees 
ARGENTINE FORK-TAILED NIGHTJAR (J liat. size). 
