get a good view
of them with my glasses; but such glimpses as I obtained revealed a
prevailing grayish, streaked with some darker color, while a glint of
yellow in their wings and tails was displayed as the birds flew from
bush to bush. When the wings were spread, a narrow bar of yellow or
whitish-yellow seemed to stretch across them lengthwise, giving them a
gauzy appearance. The birds remained together in a more or less compact
flock. They uttered a loud, clear chirp that was almost musical, and
also piped a quaint trill that was almost as low and harsh as that of
the little clay-colored sparrow, although occasionally one would lift
his voice to a much higher pitch. What were these tenants of the dry and
piney mountain side? They were pine siskins, which I had ample
opportunity to study in my rambles among the mountains in 1901.

[Illustration: _Pine Siskins_]

A mile farther down, a lone mountain bluebird appeared in sight, perched
on a gray stump on the gray hillside, and keeping as silent as if it
were a crime in bluebird-land to utter a sound. This bird's breeding
range extends from the plains to the timber-line; and he dwells on both
sides of the mountains, for I met with him at Glenwood. About a half
mile above Malta a western nighthawk was seen, hurtling in his
eccentric, zigzag flight overhead, uttering his strident call, and
"hawking for flies," as White of Selborne would phrase it. A western
grassfinch flew over to some bushes with a morsel in its bill, but I
could not discover its nest or young, search as I would. Afterwards it
perched on a telegraph wire and poured out its evening voluntary, which
was the precise duplicate of the trills of the grassfinches of eastern
North America. There seems to be only a slight difference between the
eastern and western forms of these birds, so slight, indeed, that they
can be distinguished only by having the birds in hand.

Turtle doves were also plentiful in the valley above Malta, as they were
in most suitable localities. Here were also several western robins, one
of which saluted me with a cheerful carol, whose tone and syllabling
were exactly like those of the merry redbreast of our Eastern States. I
was delighted to find the sweet-voiced white-crowned sparrows tenants of
this valley, although they were not so abundant here as they had been a
little over a week before in the hollows below the summit of Pike's
Peak. But what was the bird which was singing so blith