Concord, Mass.
1909.
July 20 [July 20, 1909]
  Clear & cool with light northerly winds.
  Red-eyed Vireos appear to sing more freely at all hours at this
season than at any other and for this reason they seem to be more
numerous now than they were in May & early June. I hear them everywhere
in the woods from morning to about sunset, even in places where the
gypsy moths have stripped the trees nearly or quite bare.
Red-eyed Vireos singing freely
  The Tanagers, like the Red-eyes, are now singing much more than
they do earlier in the summer. There are at least three or four males on
my land, one at Ball's Hill, one at Davis Hill, one or two in the woods at
the farm. I hear them at all hours but oftenest from sunrise to 8 or 9 A.M.
and again at evening when they sing as late with the twilight as the
Veeries and very much later than the Red-eyes which cease, as a rule
about sunset.
Tanagers singing
  At 6 P.M. there were about 30 Swallows skimming to & fro over the river in front of
Ball's Hill, feeding & dipping down to strike the water, either to drink or bathe,
I know not which. By 7 P.M. the number had increased to 50 or more.
The birds now flew higher (40 to 50 ft. up) and moved more in unison but
yet in rather scattered order, coursing up and down the river for a distance
or 200 to 300 yards in each direction, still feeding a little but flying for
the most past rather straight & calling a good deal. During the next half hour
they became more & more excited and erratic in their movements and
their flights more performed at higher & still higher elevations. At 7.45 they
rose so very high above Ball's Hill that they looked scarce larger than
flies. They were now flying in a close flock almost as compact in
fact, as that of Peeps or Pine Siskins and in a great ellipse, perhaps half
a mile long. A few minutes later they descended and began darting back & 
forth around & among the tops of the trees near the cabin calling incessantly. Shortly
after this they disappeared, no doubt seeking their roost in the willows just below
our camp. Most of them were Barn Swallows but I heard the calls of Tree, Bank & Eave
Swallows, also.
Evening flight
of Swallows