BIRDS OF MINNESOTA. 351 



eagles are instantly put to flight by them, and in the words of 

 Wilson, "So well known is this to the lesser birds, that as soon 

 as they hear the Martin's voice engaged in fight, all is alarm 

 and consternation. To observe with what spirit and audacity 

 this bird dives and sweeps upon, and around the hawk, or the 

 eagle, is astonishing. He also bestows an occasional bastinad- 

 ing on the Kingbird, when he finds him too near his premises, 

 though he will at any time instantly co-operate with him in 

 attacking the common enemy," The value of the Purple Mar- 

 tin to the general, or the special agriculturist is so well under- 

 stood, and so universally accepted on account of their destructon 

 of noxious insects, that for an exception, no argument is needed 

 with that class of producers to defend it. It is nearly univer- 

 sally distributed over the State. It leaves the whole country 

 almost simultaneously between the 20th and 25th of August, in 

 company with the White-bellied Swallows. Years of record 

 show that they have left the vicinity of Minneapolis on either 

 the 23d or 24th of that month. 



Note. Mr. Washburn when referring to this species in his 

 notes gathered on his second trip to the Red river valley says : — 

 "This species too, occurs about Mille Lacs, where the farmers 

 provide boxes for them. The great majority of them there, 

 however, nest with the Gulls on an island called Spirit island 

 by the Indians, lying about two miles from the southeastern 

 shore of Lake Mille Lacs. Here large numbers lay their eggs 

 in the sand, — in the crevices and fissures of the rocks, and 

 serve as allies in driving away the ravens and other birds dis- 

 posed to prey upon the eggs and young of the gulls. " 



SPECIFIC CHARACTERS. 



Bill strong, short, gape very wide, sides gradually com- 

 pressed, culmen and lateral margins arched lo tip, and the 

 latter inflected, nostrils basal, lateral, open, and rounded; tail 

 considerably forked; tarsi shorter than middle toe and claw, 

 and about equal to the toe alone; toes long, strong, lateral ones 

 equal; closed wings rather longer than the deeply forked tail; 

 tarsi and toes naked; color everywhere glossy steel-blue with 

 purple and violet reflections. 



Length, 7.30; wing, 5.85; tail, 3.40. 



Habitat, temperate North America. 



PETROCHELIDON LUNIFRONS (Say). (612.) 



CLIFF SWALLOW. 



Nowhere that my personal observation has extended, has 

 this species of sparrow been more abundant from about the 

 first of May to the 20th of August, than in this northern land. 



