Among the birds that dwell on the steep mountain sides above the "Loop" hollow are the melodious green-tailed towhees, lisping their chansons of good-will to breeze and torrent, while in the copse of asps in the hollow itself the warbling vireo and the western flycatcher hold sway, the former rehearsing his recitative all the day long, and the latter chirping his protest at every human intrusion. On a pine-clad shelf between the second fold of the "Loop" and what is known as the "Great Fill" I settled (at least, to my own satisfaction) a long-disputed point in regard to the vocalization of the mountain hermit thrush. Again and again I had noticed a peculiarity about the hermit's minstrelsy--whenever the music reached my ear, it came in two runs, the first quite high in the scale, the second perhaps an octave lower. For a long time I supposed that two thrushes were singing responsively, but here at the "Loop," after listening for a couple of hours, it occurred to me as improbable that there would invariably be a respondent when a thrush lifted up his voice in song. Surely there would sometimes, at least, be solo singing in the thrush realm. And so the conclusion was forced upon me that both strains emanated from the same throat, that each vocalist was its own respondent. It was worth while to clamber laboriously about the "Loop" to settle a point like that--at all events, it was worth while for one admirer of the birds. HO! FOR GRAY'S PEAK! [Illustration: PLATE VI TOWNSEND'S SOLITAIRE--_Myiadestes townsendii_] [Illustration] By the uninitiated it may be regarded simply as fun and pastime to climb a mountain whose summit soars into cloudland; in reality it is serious business, not necessarily accompanied with great danger, but always accomplished by laborious effort. However, it is better for the clamberer to look upon his undertaking as play rather than work. Should he come to feel that it is actual toil, he might soon weary of a task engaged in so largely for its own sake, and decide to expend his time and energy in something that would "pay better." Moreover, if he is impelled by a hobby--ornithology, for instance--in addition to the mere love of mountaineering, he will find that something very near akin to wings has been annexed to the climbing gear of which he is naturally possessed.