May, 1907 ■ yy 



BIRDS COI.I.ECTED BY W. W. BROWN, JR., ON CERROS, SAN BENITO 



AND NATIVIDAD ISEANDS IN THE SPRING OF 1906, WITH 



NOTES ON THE -BIOTA OF THE ISEANDS 



By JOHN E. THAYER and OUTRAM BANGS 



THE following lists and notes, based on birds collected on Cerros, San Benito 

 and Natividad Islands off the northern coast of Dower California by W. W. 

 Brown, Jr., in the spring of 1906, may add a little to our knowledge of the 

 ornis of these barren, inaccessible islands. The field was in no sense a new one, 

 such good bird collectors as Streets, Belding and Anthony having worked it; but it 

 w^as desirable to get more specimens of some of the species found there, especially 

 the three small land birds peculiar to the islands — 7 /iryoniaiies hezvickii cerroensis 

 (Anthony) of Cerros, and Carpodaciis mcgregori Anthony and Passoruliis ros- 

 t fat us sandonnn (Ridg.) of San Benito. 



Most of the literature bearing on the ornis of these islands is rather frag- 

 mentary consisting of brief descriptions of new forms, or short notes on the breed- 

 ing or other habits of some of the birds. Belding, however, published (Proc. 

 U. S. Nat. Mus. Vol. 5, pp. 530 to 532, 1882) a list of twenty species of birds 

 seen or taken by himself during a stay of twelve days in April, on Cerros Island. 

 Anthony's descriptions of new forms and accounts of the breeding of petrels and 

 other birds are scattered, but appeared chiefly in the Auk. 



In the spring of 1906, W. W. Brown, Jr., visited these islands while on his 

 way to Guadaloupe and made small collections of birds, mammals and reptiles. He 

 sailed from San Quentin, accompanied by Mr. H. W. Marsden as assistant, on the 

 little schooner "La Fria" of ten tons burden on March 25, reaching Cerros Island 

 in twenty-four hours. Here he planned to stay a week and a vessel was to call for 

 him at the end of that time, but for some reason never explained a month elapsed 

 before the "Santa Barbara," fourteen tons burden, came to take him off. This 

 delay was serious as there were so few birds on Cerros that it was a waste of time 

 staying there and it delayed his visit to Guadaloupe till much later in the season 

 than he had planned reaching there. 



During this month Mr. Brown and Mr. Marsden made a short trip to Nati\'i- 

 dad Island; they, however, found no small land birds there. 



On April 24, Brown and Marsden accompanied by Ignacio Oroso, a Mexican 

 hunter, sailed from Cerros for Guadaloupe, but made a stop of two days at the San 

 Benito Islands. 



In another paper we intend gi\'ing an account of Mr. Brown's experiences 

 among the birds of Guadaloupe and here only list such species as he took on the 

 three smaller islands that he ^'isited on his way thither. An account of each 

 island, taken from Mr. Brown's notes, precedes the list of birds that he secured 

 there. 



CERROS ISLAND 



"Cerros Island is nearly twenty-one miles long, north and south, and in width 

 it varies from three miles near its northern end to nine miles near its southern end. 

 The southern end of the island is twelve and one-half miles from the mainland of 

 the Peninsula of Dower California. It is of volcanic origin, a mass of high, abrupt 

 peaks, the highest being 3950 feet in altitude. The northern part of Cerros is com- 

 paratively fertile,. the crests and northern slopes of the mountains being covered bv 



