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64 THE CONDOR Vol. XlII stream, which flows in a southeasterly direction, issues from a narrow canyon into a broad drainage basin, from one to several miles in width, with a flood-plain half a mile or more wide. It should be explained, however, that the entire creek is now take n up and held in reservoirs for irrigation. On the north side the land rises by a steep, continuous slope for a distance of several hundred to perhaps a thousand ?eet, but on the south a series of low hills leads gradually up from the flood-plain to the rim of the valley. Besides the main car?yon two or three small tributary canyons enter the valley within the limits c6vered by our observations; only one of these, however, contains a permanen[stream. This is known as Pole Creek, and is very small, in fact quite disappearing in places, where it sinks among the rocks and sand of its bed. The main canyon is from one to several hundred yards in width, with steep, often pre9ipitous walls. So far as the vegetation of the region is concerned, the flood-plain association of plants is of course sharply marked off from that of the upland or sage-brush sec- tion. The former consists largely of a tall rank grass (Elyrnus condensalus), known as rye-grass, together with other grasses, sedges, and rushes, and where 'the soil is strongly alkaline, of various halophytic species. , Certain tall weeds, espec- ially the common sunflower (/-[eliauthus annuus) also abound. Along the imme- diate bank of the creek there is a more or less continuous belt of willow thickets, consisting mainly of shrubby species, commonly not much over fifteen feet in height. but frequently forming a very dense growth. At Bfogart, however, there is a tract'of some fifteen or twenty acres of what may be designated timber, con- sisting wholly of xvillow trees, some of which reach a height of thirty or forty feet and a diameter of twelve or fifteen inches. Among the trees is a dense tangled undergrowth of red osiers, rose bushes and other shrubs, with various rank weeds, especially thistles and nettles, forming all together an almost impenetrable jungle. In the canyons are considerable thickets of willow, some shrubby birches ( I?etula microphylla), occasional small shad-berry trees ( Amelanchier cusickii ?), and also alders and chokecherries, and numerous clumps of cottonwood (t>opulus angusttfolia), the trees sometimes sixteen inches in diameter. Excepting these narrow canyons and the flood-plain of Willow Creek, the whole area over which our observations extended is an almost uninterrupted xvaste of sage-brush and such other xerophytes as usually accompany it. It is needless to say that the character of the vegetation constitutes the domi- nant factor in determining the avian life in each of the sections above indicated. In the flood-plain area birds were not, in general, remarkably plentiful; however, the bit of willow timber displayed an. abundance of individuals and variety of species rarely seen surpassed in any section of equal extent. Some idea may be gained of the richness of this locality from an examination of the list which follows. The chief requirements,protection from enemies and from the elements, and an abundant food supply, were here to be met with as nowhere else for miles around. Insects appeared to be remarkably plentiful; one would scarcely find them more so in a tropical forest. This lower portion of the valley has been in ranches for many years, and a considerable part of it is devoted to alfalfa raising. Abo_ut the ranch houses are considerable orchards and shrubbery and tall Lombardy poplars, forming a favorite resort for a number of species, which were here found in great abundance. Fur- thermore, large numbers of Fringillidae were noted in the extensive patches of sun- flowers, ihe seeds of which, when in season, probably formed their principal food. In Willow Creek Canyon birds were found in only moderate numbers, but in the little canyon of Pole Creek both species and individuals were abundant.