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 



