GREAT BLUE SWALLOW. 69 



GREAT BLUE SWALLOW.* 

 Progne Dominicensis. 



Hirundo Dominicensis^ LrxN. 



Hinmdo albiventris, Vieill. Ois. Am. pi. 28. 



As closely allied to the Purple Martin, in 

 manners, as in form and colouring, I long mis- 

 took the present bird for that well-known species, 

 as I think others have done also. The white belly 

 is, however, a sufficient mark of distinction. It is 

 very common, at least in the lowlands and inferior 

 mountain ranges, during the summer; some remain 

 with us through the winter, but as there is a very 

 marked diminution of their numbers, I conclude 

 that a large body of them migrate on the approach 

 of that season, probably to Central America. About 

 the end of March we see them in great numbers, 

 assembled early in the morning on the topmost 

 branches of the lofty cotton trees, which at that 

 season are leafless. On these they crowd so closely, 

 side by side, that I have known five to be killed at 

 one discharge. In the autumn we observe exactly the 

 same habit. Perhaps we may trace some analogy 

 here to those periodical congregations of other 

 species which are known to be connected with 

 migration. 



* Length 8 inches, expanse 15^, flexure 5^, tail 2, rictus ^S, beak 

 along culmen ^, tarsus i§, middle toe ^, hind toe ^, outer toe slighter 

 longer than inner. 



Irides dark hazel. 



