The Tree Swallow 
131 
Beauty of the 
Flocks 
estimating from photographs and from the counting of the live birds — - 
were collected on the telegraph-wires and in the adjoining fields, and not 
a single specimen of any other species could be found in the flock. 
Beside the road is a small brook with two or three exposed pools, 
and here was a great oval whirl of birds, all going in the same direction, 
each in passing dipping for a drink, then rising to re-take its place in the 
line. Now and then some returned to the wires or other joined the drink- 
ers, but the numbers were so great that a collision seemed unavoidable. 
A large part of the flock had settled in a pasture some distance away, 
in so close a group that they made a spot of blue on the short grass. 
Crossing over to these I found them quietly enjoying the sunlight, and, 
as I approached from the southwest, all had their backs toward me, show- 
ing to perfection the beautiful steel-blue of the feathers. Most of the 
time they were still, though now and then one under- 
took to walk a few inches, if, indeed, such a ridiculous 
hobble could be called a walk. But forty feet was 
near enough for a person — then those nearest me rose, and, passing 
over the others, alighted in front of them, and so they moved regularly 
on before me. 
Four or five times during an hour and a half the birds on the tele- 
graph-wires rose in a body, with those drinking at the brook, while the 
flock from the pasture hurriedly crossed the intervening fields to join 
them. For a moment the very air seemed full of swallows ; then, rising 
higher, they separated into smaller flocks, turning back and forth, meeting 
again, describing curious figures as smoothly and easily as if going 
through a long-practiced drill. After a few minutes, they either returned, 
a few at a time, to their former perches, or gradually scattered over the 
fields and woods, and in a little while came streaming back, a long river 
of swallows, to alight once more. 
As the morning advanced their numbers gradually diminished, and at 
3 p. m. about thirty remained. For three or four days after that these 
Swallows were present in great numbers, continuing their drill, after 
which I noticed no more than usual. 
Like all its kin, the Tree Swallow rids our atmosphere of many 
troublesome gnats and other insects. Forbush says that it is probably 
more useful than the Bank Swallow, for it is oftener seen about houses 
and gardens, where it catches flies, mosquitos, and 
noxious insects. “Leaf-eating beetles, canker-worms, Insect Prey 
cabbage-butterflies, small moths, click-beetles, rove- 
beetles and other beetles, winged ants, and many other flying insects 
form part of its food.” 
The Tree Swallow not only comes earlier and stays longer with us 
than any one of the clan, but it is the only one of the family to winter 
in the United States, remaining during that season wherever in the 
Southern States frost is rare (and hence insects may continue on the 
wing), but most of them go to Central America. Those that stay north 
of the tropics, however, are occasionally exposed to the danger of starva- 
tion when a sudden drop in the temperature not only impairs the bird’s 
