A few minutes later I heard a vigorous and musical chirping in the pine bushes, and, turning aside, found a flock of small, finch-like birds. They flitted about so rapidly that it was impossible to 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.