Concord, Mass.
1893
Aug. 24
  Another heavy storm with torrents of rain and a violent
wind, this time from the S.E.
  In the afternoon I sailed to Ball's Hill and paddled
back. The rain had ceased but the wind still came
in angry gusts at times. The air was very soft & damp.
Fleecy cloud masses drove across the sky. The leaves
were flouted & tossed about, the maples showing silvery
white in the distance.
  Again great numbers of Swifts at Beaver Dam &
Rice Island but nowhere else a single bird. Their marked
preference for these stretches of river must be connected
in some way with the presence of the wild rice which
in both places forms extensive beds while elsewhere it
merely fringes the banks. There were four Martins with
the larger flock of Swifts and Swallows of three or four
species in each. The Swifts dashed about at such
tremendous speed and passed or crossed one another's lines
of flight so closely that it seemed wonderful that
they did not occasionally come into collision. Repeatedly
this afternoon, as well as on many other occasions of late,
a bird flying at full speed & passing close over my
head made, with its wings doubtless, a peculiar sound
very like that of a humming top. Only a small
proportion of the total number made this sound
which, by the way, I do not recall ever hearing except
at about this season. Perhaps it is produced only by
the young or by adults at a certain stage of the
moult when the wings are lacking a portion of the quills.
[margin]Swifts[/margin]