Concord, Mass.
1901.
June 17
  Brilliantly clear with light variable winds and
long intervals of calm. Very warm.
  Walked twice to the farm and back, in the forenoon
and late in the afternoon. Saw or heard a large
number of birds but nothing of any particular
interest. A Hairy Woodpecker was calling at Ball's Hill
this morning and another at Pulpit Rock in the
afternoon. Most of the birds are still singing freely
but Black & White Creepers have been nearly silent of 
late and I have not heard a Nashville or Golden-winged
Warbler for more than two weeks - ie since June 2nd.
Thrashers have also ceased singing and Cat birds
are nearly silent. Robins are still singing at
morning and evening. Cuckoos seem to have increased
in numbers of late. I heard one Yellow bill and 
several Black bills to-day.
  As I was returning from the farm late this
afternoon I heard in the woods near Pulpit Rock
an exceedingly loud & most peculiar whistle given
dozens of times at intervals of perhaps half a minute.
At first I suspected that it was made by a man
but on studying it carefully I became convinced
that it was the cry of some wild creature. After
a little the author of the sound shifted its position
100 yards or more in the interval between the calls. 
This satisfied me that I was listening to the cry
of some bird, probably a Hawk although the call
was wholly new to me. When I tried to approach the
spot the sound ceased & was not again renewed.
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