between the northern parts of Stanislaus and Tuolumne counties and the northern part of Butte, southwestern Plumas and Sierra counties.
I have made observations at many localities in this part of the State, in the tule swamps, river bottoms, plains, foothills and coniferous forests of the Sierra Nevada Mountains at all altitudes, kept a record of the birds, but have not thought it necessary to burden my notes with a long list of localities. The summer residents are the same in northern Tuolumne County as in northern Butte, though a few species become more numerous with increase of latitude, and there is a corresponding decrease in altitude of the breeding range of some of the mountain species. There is little difference in the resident species of the northern Sacramento Valley and the southern San Joaquin Valley, and I believe the avifauna of Central California nearly represents that of the State north of about the 35 of latitude, east of the coast mountains and west of the Great Basin, though a considerable portion of this tract has not been ornithologically explored, the Sierra from near Tehachapi to Alpine county having been quite neglected.
I am quite confident that few, if any, species have escaped my notice in Central California, except a few which probably visit the high Sierra Nevada in winter, from the north, when snow is so deep as to prevent exploration.
The Pacific District has an area, exclusive of British Columbia, of 434,000 square miles. California alone is more than twice as large as the six New England States, has a great diversity of surface and climate, and is as long as from Florida to Lake Erie facts sufficient to prohibit positive opinions until after a more thorough exploration.
The nomenclature is that at present sanctioned by the
