BREWSTER : BIRDS OF THE CAPE REGION, LOWER CALIFORNIA. 141 



Ammodramus rostratus sanctorum (Ridgw.). 



San Benito Sparrow. 



Passerculus sanctorum Ridgwat, Proc. U. S. Nat. Mus., V. 1883, 538 (San Benito I.). 

 P [ai^sercHlus] sanctorum KiDGWAY, Loc. cit., 538, 539 (crit.). 

 Ammodramus (Passerculus) sanctorum CouES, Auk, XIV. 1897, 92, 93 (crit.). 

 Ammodramus sanctorum McGregor, Osprey, II. 1897, 42 (descr. habits, nest and 



eggs from San Benito Islands) ; Auk, XV. 1898, 264, 265 (descr. female, 



Juvenal plumage). 



Among the Passerculi collected by Mr. Frazar in or near the Cape Kegion 

 are si.\ specimens which, although variously intermediate in size between 

 A. rostratus and. A. r. guttatus, are colored more nearly like the latter. On 

 comparing them with eleven examples (including the type) of A. r. sanctorum 

 from the San Benito Islands, which Mr. Ridgway has been kind enough to 

 send me for examination, I find that five belong, without question, to that 

 recently separated — or rather resuscitated — insular race. The sixth bird is 

 smaller than any of the others, and, indeed, not larger than one or two of the 

 largest representatives of halophilus from Point Abreojos, but in respect to 

 coloring it appears to agree more closely with sanctorum, to which, not without 

 hesitation, I have finally decided to refer it. 



This subspecies, originally named by the late Dr. Coues upwards of twenty- 

 five years ago, but not until some time afterwards formally recognized either 

 by him or by other ornithologists, is represented, as I have just said, by several 

 skins in Mr. Frazar's collection, obtained at Carmen Island on March 6, and at 

 San Jose del Cabo between October 10 and Novemljer 9. Mr. Ridgway has 

 also mentioned three specimens "resembling 'P. sanctoric7n' in coloration" 

 which were collected by Mr. Belding at La Paz in January and February. 

 From this we may infer that the bird is of regular and not very uncommon 

 occurrence, in or near the Cape Region, in atitumn, winter, and early spring. 

 It is believed to be confined to Lower California at all seasons, and its only 

 known breeding grounds are on the San Benito Islands. These islands, three 

 in number, are described by Mr. R. C. McGregor as " situated about twenty 

 miles west of Cerros Island. The two largest have each an area of several 

 square miles and are from 200 to 400 feet high. The islands are quite dry 

 ditring the summer season. For nine months almost no rain falls, while the 

 porous and rocky character of the soil precludes the existence of springs or 

 the formation of marshes and pools. The flora is semi-desert in nature. 

 Several species of cacti and some small insular plants make up the vegetation, 

 there being nothing which attains the size of a shrub or tree. Both the large 

 islands are very hilly and these have been cut itp by the heavy winter rains. 

 The gullies so formed are often difficult or impossible to cross. It will thus 

 be seen that the home of Ammodramus sanctorum is essentially different from 

 that of any of the salt marsh Ammodrami." 



