NIGHTJARS. 



45 



also a gexxas (Scotornie) 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 

 McLcropdalis, 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 

 (Hydropsalia fiircifero), 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 Rios, 

 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 ( nat. size). 



