Concord, Mass.
1901.
July 14
(No 4)
I now doubt the accuracy of those earlier observations
for during the past week I have never once seen the
birds flutter their wings sufficiently to produce the rumbling
without at the same time changing their positions or
at least their foot hold.
  The bird which I took to be the female usually went
directly or very quickly to the nest and alighted on
its outer rim when she would sometimes sit for hours
with her bill nearly touching the walls of the
chimney. The tips of her folded wings extended out
behind half way across the flue looking, when viewed
from below, like two slender, curved, converging lines
drawn on the field of bright light that entered the
chimney from above. Her mate spent much of his idle
time clinging to the chimney just above the nest but
sometimes during the day, and invariably at the
near approach of night, he would crowd himself into
the nest by his posterior side taking exactly the same
position which she habitually assumed. Long after
dark, in fact usually up to the time when we went to bed,
we heard the birds fluttering their wings or calling to
one another at frequent intervals. Their vocal notes were
the same as those which they use when
flying about by day but their twittering, when heard
at night in this chimney, seemed to me infinitely
more tender and musical than it ever is by day.
I must confess that I could not understand why they
made the rumbling sound so much after they had
settled themselves in the nest since
it is not likely that they were moving about the
chimney in the darkness but I finally concluded
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