Notes on the Breeding Coastal and Insular Birds of Central Lower California

Abstract

T HE PURPOSE of this paper is to ' draw from my own experience bits of information which either appear to be new or which seem to be of sufficient importance to deserve repetition. Though no attempt will be made to cover all the field, I will list the breeding birds I know to occur on the small islands of Baja California de1 Norte on the Gulf side. Isla de1 Angel Guardia I have not yet had an opportunity to visit. AUKLETS Auklets are so far known only from the Pacific side of the peninsula. I have found the Cassin Auklet (P~ychorumphus &r&us) breeding freely as far south as San Geronimo Island. I have both eggs and skins of this species taken for me by Mr. Ed. Seechrist of San Diego, who collected them about April 10, 1927, on San Roque and Asuncion ' islands. The breeding dates in Mexican waters are very con-fusing. Early April on the Coronado Islands near San Diego is the time, to look for fresh eggs; yet there are young in the burrows of San Roque at that time, while fresh eggs are to be found on San Geronimo as late as the middle of May. Although the birds lay but one egg I took what appears to be a genuine set of two on San Geronimo, May 21, 1926. As far as the eye can tell they were laid by the same bird. Their incubation was identical, barely started. MURRELETS