Although the two species hunt, fly and roost together, they do not hold their meetings together. The Whitebreasts' assemblages are held over water. They betake themselves to a pond or lake, and find a perch on the pods, stalks and projecting leaves of the lotus (_Nelumbo lutea_), with which some of these shallow waters of the marsh are literally covered. There is a small pond only a quarter of a mile from the sunflower patch, and this is now just full of Whitebreasts. Now and then a little cloud of them rises from the pond, and after a few evolutions settles down again. There are only a few hundred; the height of their autumnal wandering is several weeks behind that of the Eaves. These are most numerous in late 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, and some Barn Swallows and Whitebreasts, which two species are not numerous breeders in this region.
[Illustration: TREE OR WHITE-BREASTED SWALLOWS
Immature birds on the ground gathering nesting material, which they drop after carrying a short distance, thus apparently giving a premature exhibition of the nest-building instinct
Photographed from nature by Frank M. Chapman, Leonia, N. J., August, 1897]
As soon as migration begins, about the middle of August, the Eaves are greatly reinforced, and for the next four weeks enormous numbers 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, employing mainly the first 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 more numerous in early September, and many remain, with a few Barn Swallows, into October, but the latter are never conspicuous at this roost. Martins and Bank Swallows are only accidental visitors to this roost. The Whitebreasts remain numerous to the middle of October, and small detachments linger even a week longer.