1902
Nov 8
Concord, Mass.
  At 2.15 P.M. I heard a Great Horned Owl hoot once in
the dense pines on the Prescott Hill. The sun was shining
brightly at the time & there was almost no wind stirring.
About two hours later (4.20 P.M.) a pair of these Owls
began a wonderful serenade to which I listened attentively &
with the keenest enjoyment for upwards of half-an-hour
when both became silent. One of them within fifty yards of
me in the large dense pines on the ridge above the Glacial Hollow
invariably uttered five notes: -hoo, hoo-hoo; hoo; hoo. There
was regularly a short but well-marked pause after the first
note, the second and third notes were given in rapid
succession, a carefully-measured and impressively long interval
followed the third note while the interval between the fourth
and fifth notes was about half as long as that between the
first and second notes and that separating the third & fourth.
The bird's voice was, I think, the deepest and most
sonorous that I have ever listened to from any Bubo, while
the carefully-measured intervals made it tremendously
impressive. The other bird was apparently about two hundred 
yards distant & downstream on Davis's Hill. Its hooting was
radically different. Usually it uttered eight notes (hoo, hoo-
hoo-hoo, hoo-hoo-hoo, hoo) but occasionally there were
nine (hoo-hoo, hoo-hoo-hoo, hoo-hoo-hoo, hoo. Its voice
was lighter and more woodeny than that of the first bird
and its notes given so rapidly that the commas which
I have just used to separate them should perhaps have
been omitted. Indeed the notes followed one another
in nearly if not quite as quick succession as do those 
of the Barred Owl. Usually this bird hooted in response
to its mate but on two occasions it uttered the full
series of notes just described, twice in rapid succession