barred owl:

Wa--wah--wa--wah Wa--wah--wa--hooooo-aw.

He replied with the last line, and the answer came a repeat of the whole
chant, showing that it might be owl, it might be man; but it was not the
right man, for the final response should have been the hooooo-aw. Rolf
never knew whence it came, but gave no further heed.

For a long time he sat in a dark corner, where he could watch the road.
There were sounds of stir in the direction of Plattsburg. Then later,
and much nearer, a couple of shots were fired. He learned afterward that
those shots were meant for one of his friends. At length there was a
faint tump ta tump ta. He drew his knife, stuck it deep in the ground,
then held the handle in his teeth. This acted like a magnifier, for now
he heard it plainly enough--the sound of a horse at full gallop--but so
far away that it was five minutes before he could clearly hear it while
standing. As the sound neared, he heard the clank of arms, and when it
passed, Rolf knew that this was a mounted British officer. But why, and
whither?

In order to learn the rider's route, Rolf followed at a trot for a mile.
This brought him to a hilltop, whither in the silent night, that fateful
north wind carried still the sound

te--rump te--rump te--rump.

As it was nearly lost, Rolf used his knife again; that brought the rider
back within a mile it seemed, and again the hoof beat faded, te--rump
te--rump.

"Bound for Canada all right," Rolf chuckled to himself. But there was
nothing to show whether this was a mere despatch rider, or an advance
scout, or a call for reinforcements.

So again he had a long wait. About half-past ten a new and larger sound
came from the south. The knife in the ground increased but did not
explain it. The night was moonless, dark now, and it was safe to sit
very near the road. In twenty minutes the sound was near at hand in
five, a dark mass was passing along the road. There is no mistaking the
language of drivers. There is never any question about such and such a
voice being that of an English officer. There can be no doubt about
the clank of heavy wheels--a rich, tangy voice from some one in advance
said: "Oui. Parbleu, tows ce que je sais, c'est par la." A body of about
one hundred Britishers, two or three wagons, guns, and a Frenchman for
guide. Rolf thought he knew that voice; yes, he was almost sure it was
the voice of Francios la Colle.

This was important but far from conclusive. It