138 
GREEN-BLUE, OR WHITE-BELLIED SWALLOW. 
blue ; the former has the whole rump white, and the legs and 
feet are covered with short white downy feathers, the latter 
has nothing of either. That ridiculous propensity in foreign 
writers, to consider most of our birds as varieties of their 
own, has led them into many mistakes, which it shall be the 
business of the author of the present work to point out, 
decisively, wherever he may meet with them. 
The White-bellied Swallow arrives in Pennsylvania a few 
days later than the preceding species. It often takes posses- 
sion of an apartment in the boxes appropriated to the Purple 
Martin; and also frequently builds and hatches in a hollow 
tree. The nest consists of fine loose dry grass, lined with 
large downy feathers, rising above its surface, and so placed 
as to curl inwards, and completely conceal the eggs. These 
last are usually four or five in number, and pure white. 
They also have two broods in the season. 
The voice of this species is low and guttural ; they are 
more disposed to quarrel than the Barn Swallows, frequently 
bushes ; and they sometimes in the beginning of autumn, as mentioned by our 
author, collect on the shores or sandbanks of rivers, in considerable numbers. 
About the end of July, in the present year, I had an opportunity of seeing the 
latter incident take place with our common Sand Martin ( H . riparia,) one 
very hot evening, when residing on the shores of the Solway Frith, where the 
beach is unusually flat and sandy. Several hundreds of these were collected 
upon a space not exceeding two acres, most of them were upon the ground, 
a few occasionally rising and making a short circuit. At this part, a small 
stream entered the sea, and they seemed partly resting and washing, and 
partly feeding on a small fly that had apparently come newly to existence, and 
covered the sands in immense profusion. None of our other species mingled, 
though they were abundant in the neighbourhood. 
The American Bird is also remarkable as being a berry eater, an occurrence 
nearly unknown among the Hirundinidce. Neither is their breeding in holes 
of trees frequent among them. The only instance of a similar propensity, is 
one related of the common Swift, in Loudon ' s Magazine of Natural History , 
which, however, is a species more likely to suit itself to circumstances of the 
kind, as it appears to have done in this instance, where it formed its breeding 
place in the deserted holes of Woodpeckers. Audubon has traced their 
migrations through the year, and has proved that they winter in Louisiana. I 
believe they belong exclusively to the New World. — E d. 
