222 The Chimney Swift 
The swifts feed their young during the greater part 
of the night, and the noise made by their wings while 
passing in and out of the chimney often resembles 
the low rumbling of distant thunder. This is more 
pronounced by the time the second brood is reared, 
but it becomes unbearable only when, as sometimes 
happens for a week or two, a few hundred swifts 
take up a temporary residence in an old fashioned 
chimney, before starting on their southern journey. 
I remember very distinctly flocks of this kind which 
assembled at my father’s old farmhouse and took 
up their abode in the “parlor” chimney. The flocks 
varied from a hundred to two or three times that 
number, and the usual time of assembling was early in 
September. Many a time at dusk I have watched the 
birds flying in a large circle above the house, and then 
all at once, even while I gazed, the mass would change 
form—those on the inner part gradually descending 
and the circle narrowing until it resembled an in- 
verted cone with rapidly moving sides, which swept » 
lower and lower, until the birds at the apex dropped 
into the chimney, soon to be followed by the whole 
flock. I saw something of the same thing a few sum- 
mers ago in Princeton, New Jersey, although on a 
much larger scale; chimney swifts varying in number 
from twelve to fifteen hundred gathered each night, 
