1893
May 29
Concord, Mass.
  Cool with light easterly winds in the afternoon. Early morning
cloudy but the sun out after 10 A.M.
[margin]Ball's Hill[/margin]
  To Ball's Hill with D.C. French taking both canoes and
paddling slowly down. A long walk to Davis Swamp &
beyond in the forenoon, dinner at the cabin, a sail to
Carlisle bridge &[and] back in the afternoon, and a quiet
paddle up river to the Buttricks' at evening completes the brief
record of a delightful day.
  We saw and heard a remarkable number of birds, more
I think, than I have noted on any previous day this
year. The strange silence which oppressed them earlier in
the month was broken less than a week ago but of late
they have sung with normal frequency and freedom. To-day
the singing was much above the average both in quantity &
quality. The air was still & just pleasantly cool conditions
especially favorable for birds to sing freely & for their songs
to carry well. The period of comparative - nay almost total - silence
just referred to is still an unsolved mystery but I now
believe that it was caused largely by the extreme &
unseasonable heat which prevailed at the time. Furthermore
it is probable that there were not then as many birds
here as we supposed. Indeed I am convinced that for
the past week or more large numbers of our common
summer birds have arrived each night. In other words
most of the species sent on only a few pioneers
at this usual time of arrival the great bulk of their
numbers following in successive detachments. The extreme
scarcity of more northern breeding birds among these
later incursions redered them inconspicuous. 
[margin]General
resumption
of bird singing
after long
interval of
silence[/margin]