VOL. T.] Distribution of Land Birds. 295 



of that ravine there grow In a small space a dozen or more clumps 

 of this species, and in some of them the caudex Is quite well devel- 

 oped, six to eight inches In height, and three to four In diameter. 

 These caudlces are, however, very deceptive ; they are firm and 

 mossy on the outside, but section shows the rootstock to be less 

 than an Inch in dian\eter, the remaining thickness being made up of 

 the bases of former fronds, compacted and covered by a mass of 

 short roots. The structure of the stems of the specimens at the 

 Park has not been examined, but is undoubtedly the same. 



THE GEOGRAPHICAL DISTRIBUTION OF LAND BIRDS 



IN CALIFORNIA. 



BY CHARLES A, KEELER. 



III, The Sonoran Province and Transition Region. 



By far the greater part of the State is occupied by the Sonoran 

 Province, which Includes all the non- mountainous regions. It Is 

 divided into two Important Areas (as has been already explained), 

 the Callfornlan and Sonoran, while the Great Basin Area also reaches 

 the State along Its eastern slope. The Callfornlan Area comprises 

 the great central valley district, being the largest and mo^st distinctive 

 region of the State. For this very reason, however, Its limits are less 

 sharply marked and it has fewer species exclusively confined to it 

 than any other Area. Indeed, it seems to penetrate nearly all parts 

 of the State where the oaks grow, although having its center of dis- 

 tribution in the valleys of the Sacramento and San Joaquin rivers. 

 On this account it is impossible to find any one species, the breed- 

 ing range of which definitely marks the Unilts of this Area, although 

 the ruddy horned lark (Otocoris alpesiris rubca) may be taken as 

 illustrating Its more restricted bounderies, as may also the pallid 

 wren tit ( Chavicea fasciata henshawi). These, however, are mere 

 varieties, and when we come to the species distinctive of this reg^Dn 

 we find that they are nearly all found in the Transition Region as 

 well, while a few (such as the California cuckoo) even cross the 

 Sierra Nevada Mountains to Nevada. Of the forms which are very 

 characteristic of the Callfornlan Area and found also in the Transi- 

 tion Region, the following are cofnspicuous examples: Dry abates 

 nuitaltii, Mela7ierpes formicivonis bairdi, Trochilus aiexandri. Pica 



