GREEN-BLUE, OR WHITE-BELLIED SWALLOW. 139 



martin is blue black above, the present species greenish 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 de- 

 cisively, wherever he may meet with them. 



The white-bellied swallow arrives in Pennsylvania a few days 



motion of the wings. In their other forms they hardly differ, though 

 almost any one will say this is a martin, that a swallow. I am inclined 

 to keep them as a subordinate group, and there also would be placed 

 the water martins, which have already been made into a genus by Boje. 

 They are all nearly of the same form, are gregarious, and build and feed 

 in large companies. 



The white-bellied swallow bears more analogy to the water martins 

 than that of Europe, or those which frequent inland districts. Accord- 

 ing to Audubon, they sit and roost on the sedges and tall water plants, 

 as well as upon the bushes ; and they sometimes in the beginning of 

 autumn, as mentioned by our author, collect on the shores or sand- 

 banks 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 (II. 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 Avere abundant in the neigh- 

 bourhood. 



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. — Ed. 



