378 BULLETIN 195, UNITED STATES NATIONAL MUSEUM 



William Brewster (1902) says: "It is resident and rather generally 

 distributed in the Cape Kegion, where, however, it does not seem 

 to occur at elevations much exceeding 3,000 feet. Mr. Frazar found 

 it common in the neighborhood of La Paz and San Jose del Rancho, 

 somewhat less numerous at Triunfo, and 'very scarce' at San Jose 

 del Cabo." 



Griffing Bancroft (1930) writes: "These thrashers are relatively 

 common wherever there is any considerable growth of small cactuses. 

 Their distribution is in direct proportion to the density of the re- 

 quired growth. It is, therefore, peninsula-wide and unaffected by 

 altitude or climate except in so far as those factors determine the 

 abundance of the cactus. That growth is most dense near the ends 

 of the cross section. It comes to an abrupt termination, together 

 with the habitat of these thrashers, where the sand dune association 

 begins." 



In some notes recently sent to me Bancroft says : "Beginning at the 

 northern limit of the Vizcaino Desert the habitat of the San Lucas and 

 Mearns's thrashers skirts the foothills of Sierra San Pedro Martir, 

 on the westerly side, and just below San Quintin, swings abruptly to 

 the east. South of the Sierra, it reaches both the Pacific and the 

 Gulf coasts, and includes the whole interior, wherever there are suitable 

 associations. 



"The territory described is coincidental with the Lower Sonoran 

 Zone in Lower California, except for the extension of the Colorado 

 Desert faunal area. The latter occupies the northeastern corner of 

 Lower California, from the international boundary south to the 

 eastern side of Sierra San Pedro Martir. It is important to notice 

 that in the entire region occupied by cinereum, there is also to be found 

 Lophortyx calif omica. Where that quail is replaced by Lophortyx 

 gamheli, there are none of these thrashers. 



"It was remarked that, within the area specified, these thrashers are 

 to be found wherever associations are suitable. These might be de- 

 fined as semiriparian — and that in a country wholly without streams. 

 The birds do not find what they need in or along river beds that are 

 scoured by flash storms. They do like what perhaps are extinct 

 stream beds with a poor apology for soil and with broken lines of 

 scattered mesquite, palo verde, and ironwood; but always a certain 

 amount of minor vegetation. 



"On the whole, cinereum is probably more closely associated with 

 cholla and garambuUo than with any other form of vegetation — and 

 this despite the fact that the bird will follow these cacti up caiion 

 walls, but not onto the open mesa above, and despite the fact that, in 

 many semiriparian associations, the thrasher is nearly as common as 

 it is anywhere in regions totally devoid of any form of cactus." 



