o marvellous an exploit on the wing.

I never worked harder to earn my salary than I did to climb that steep
and rugged mountain side; but at last I reached and penetrated the zone
of pines, and finally, in an area covered with dead timber, standing and
fallen, two feathered strangers sprang in sight, now flitting among the
lower branches and now sweeping to the ground. They were not grosbeaks,
that was sure; their bills were quite slender, their bodies lithe and
graceful, and their tails of well-proportioned length. Save in color,
they presented a decidedly thrush-like appearance, and their manners
were also thrush-like.

Indeed, the colors and markings puzzled me not a little. The upper parts
were brownish-gray of various shades, the wings and tail for the most
part dusky, the wing-coverts, tertials, and some of the quills bordered
and tipped with white, also the tail. The white of both wings and tail
became quite conspicuous when they were spread. This was the feathered
conundrum that flitted about before me. The birds were about the size of
the hermit thrushes, but lither and suppler. They ambled about
gracefully, and did not seem to be very shy, and presently one of them
broke into a song--the song that I had previously heard, only it was
loud and ringing and well articulated, now that I was near the singer.
Again and again they lifted their rich voices in song. When they
wandered a little distance from each other, they called in affectionate
tones, giving their "All's well."

Then one of them, no doubt the male, darted from a pine branch obliquely
into the air, and mounted up and up and up, in a series of graceful
leaps, until he was a mere speck against the blue dome, gyrating to and
fro in zigzag lines, or wheeling in graceful circles, his song dribbling
faintly down to me at frequent intervals. A thing of buoyancy and grace,
more angel than bird, that wonderful winged creature floated about in
the cerulean sky; how long I do not know, whether five minutes, or ten,
or twenty, but so long that at last I flung myself upon my back and
watched him until my eyes ached. He kept his wings in constant motion,
the white portions making them appear filmy as the sun shone upon them.
Suddenly he bent his head, partly folded his wings, and swept down
almost vertically like an arrow, alighting safe somewhere among the
pines. I have seen other birds performing aerial evolutions accompanied
with song, but have never known one