ten miles. Then it broadens out and its floor stretches from west to east longitudinally with but little slope for some six or seven miles, with a width of from one half to one and a half miles, making the "floor" of the Yosemite Valley. This floor is beautifully diversified by groves of cedar, yellow pine, Douglas fir, silver fir, and golden oak, interspersed among which are little meadows covered with green grasses, strawberry plants and wild, flowers, and graced by the presence of scattered deciduous trees, the principal of which is the mountain black oak. In places are bushes of blackberry, choke cherry and "cascara sagrada", upon the berries of all of which certain birds love to feast.
There is nothing in the way of topographical troubles to prevent the birds of the plains and foothills from winging their way unobstructed into this valley, whose elevation is only about 4000 feet. Were there a continuation of their accustomed food all the way up the river canyon probably most of the lower level varieties of birds would be found in the Yosemite in summer. The sides of the valley, howvever, are wonderfully abrupt, and present a great barrier to egress in a lateral direction, while upstream the valley narrows and divides into canyons which quickly mount to vastly greater altitudes. As might be expected under such couditions this valley is a meeting place for some of the forms from both lowland and highland. This the writer has found to be a fact in the fall season and it is reasonable to suppose that the early springtime would also show such intermingling. Yet some varieties that one would naturally look for in this valley are either seldom seen, or absent altogether. For instance, the nearly ubiquitous California Jay (Aphelocoma californica) seems to shun the spot, only one having been recorded during the six weeks of observation and none mentioned in the lists given above. Yet, in some localities, it frequents much higher elevations, proving that it is not the altitude that deters this species from occupying the floor of the valley.
Bird life in the fall season is very far from being evenly distributed over the valley. In a few limited areas a number of individuals may be seen in a short while, yet there are vast spaces where a person might wander around for a long time without seeing a single bird, and only hearing an occasional distant note. That is to say, this is the case at the time of year concerned in this article, from mid-August to October 1. Judging from the stories of people who have spent some time in the valley, and have taken a passing interest in its bird life, there must be many more birds in evidence in the nesting season. In fact old nests were found in places that were absolutely without bird life in the autumn time. Even then there must be large spaces in the forest that have few avian visitors, and for some unknown reason this seems to be the rule all along the Sierras, though it would seem proper to assume that where there are plenty of trees there must be plenty of insects, and that certain of the insectivorous birds would keep pace with the food supply. On occasions, the writer has wandered along through the woods and meadows for as much as an hour and a half at a time, covering say three miles of territory, even in the early morning on beautiful days, before catching sight of a single bird, and hearing during that time but little other than the distant call of a woodpecker. Late in September, however, there was such an influx of Red-breasted Nuthatches (Sitta canadensis) that no one could travel far without hearing the queer little indescribable notes of these diminutive but very busy bodies. Upon their first arrival (that is, in increasing numbers, about the middle of September) they were seldom actually seen, but later they were often met with feeding near the
