In the Spartina with the Swallows 



119 



August and early September : but, as their number decreases, that of the 

 Whitebreasts increases, reaching the height at the time the Eaves depart. 



In summer the roost belongs almost entirely to the Eaves, who 

 flock here from the surrounding country. So do the Roughwings, a 

 few hundred only, antl some Ijarn Swallows and Whitebreasts, which 

 two species are not numerous breeders in this region. 



As soon as migration begins, about the middle of August, the 



"-.'if 



TREE OR WHITEBREASTED SWALLOWS 



Immature birds on the k'"""'' gathering nesting material, which they drop after carrying a short 



distance, thus apparently giving a premature exhibition of the nest-building instinct 



Pnctojrraphed from nature by Frank M. Chapman, Leonia, N- J., August, 1897 



Eaves are greatl}- reinforced, and for the next four weeks enormous 

 niuubers are present, but it is probable that they are not always the 

 same individuals, as their numbers vary from day to day. It seems 

 they perform their migrations by stages, from roost to roost, employ- 

 ing mainly the hrst hour of the morning for their flights, spending 

 the day resting and feeding in the region surrounding the roost. 

 The substitution of arriving Whitebreasts for departing Eaves is in 

 the beginning almost imperceptible, but at last we see that the one 

 has taken the place of the other entirely. The Roughwings become 



