1906
Oct 29
(no 2) 
usually there were but two. The note although whistle-like
in character and easily imitated by the human whistle has a
peculiarly deep and also somewhat resonant quality which
makes it decidedly impressive when heard under conditions
such as those which I have just described. It is very
loud at times and really startling in its intensity. Once
tonight the bird followed it (that is the double whistle)
by a low choking sound which I do not remember
ever hearing a Saw-whet utter before. It was quite
evident that the bird heard on this occasion was
moving rather listlessly from place to place. It called
about once every two or three minutes and never more
than once (I thought) in the same spot. When it
moved its position it ordinarily went only thirty or
forty yards before alighting again. All this I could
tell by the evidence of my ears alone for I did
not once see the bird.