DOMESTIC MARTIN 25 



difference in strength or intonation. This cir- 

 cumstance appears very remarkable to me, because, 

 though two species do sometimes possess a few notes 

 alike, the greater part of their language is generally 

 different ; also because birds of the same species in 

 different localities vary more in language than in 

 any other particular. This last observation, however, 

 applies more to resident than to migratory species. 



I am inclined to believe that the Purple and 

 Domestic Martins form one dimorphic species, like 

 the Carrion and Hooded Crows of Europe, and that, 

 like these two Crows, they would inter-breed should 

 their nesting areas overlap. 



DOMESTIC MARTIN 



Progne chalybea 



Upper parts deep purple-blue; wing- and tail-feathers black, 

 glossed with steel-blue ; throat and chest ash-colour ; breast, abdomen, 

 and under tail-coverts pure white ; length 8 inches. Female similar. 



THIS species, distinguished from the Purple Martin 

 by its white underparts, ranges from Mexico to 

 Buenos Ayres, the extreme limit of its range being 

 about 250 miles south of that city. It was well called 

 Golondrina domestica by Azara, being pre-eminently 

 domestic in its habits. It never breeds in banks as 

 the Purple Martin often does, or in the domed nests 

 of other birds in trees, a situation always resorted to 

 by the Tree Martin, and occasionally by the Common 



