BIRDS OF THE PACIFIC DISTRICT. 7 



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 Ne- 

 vada 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 resi- 

 dents are the same in northern Tuolumne County as in 

 northern Butte, though a few species become more nu- 

 merous with increase of latitude, and there is a corre- 

 sponding 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 Val- 

 ley 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 ornitho- 

 logically explored, the Sierra from near Tehachapi to 

 Alpine county having been quite neglected. 



I am quite confident that few, if any, species have es- 

 caped 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 ex- 

 ploration. 



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 



