WITEIIK SWALLOWS UOOST 97 



rounding country and in the evening return to tlie 

 marsh to sleej). In the evening tliey iiy low, and 

 the altitude and time of tlieir fiiglit make tliem con- 

 spicuous. In the n\orning tliey fly high, as though 

 bound to some distant feeding ground, and at so 

 early an liour tlrat they usually esca]ie observation. 

 The evening flight, therefore, is generally considered 



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48. " Bird notes "— Tree Swallows. 



as truly migratory, when, in fact, tlie same liirds 

 doubtless i)ass over a given hjcality night after 

 night, perhaps for weeks, in returning to their 

 roosts in the marshes. 



These evening flights begin about two hours and 

 a half before sunset, when the birds, after resting 

 during the late forenoon and early afternoon, usu- 

 ally on some telegraph wire,'*'' begin to wheel and 



