Does the Black Petrel Winter Off the California Coast?
Does the Black Petrel Winter Off the California Coast?-In an effort to find concrete data in support of the current belief that Loomelaniu mdunia, the Black Petrel, is common at sea off the coast of southern California during the entire year, I have made an extended search for definite winter records, This search has not been successful.
There is the initial observation of Anthony (Auk, 11, 1894~321) over fifty yea.rs ago, when he said “I think [italics mine1 I have seen them occasinally nearly all the year.” Grinnell (Pac. Coast Avif. No. 3, 1902: 160 seemingly accepted Anthony’s remark at face value since there are no published statements of winter occurrence for the intervening period. The next record, that of Linton (Condor, 10, 1908:82), is equally unsatisfactory, that of “a dark Petrel, probably this species,” seen near San Clemente on unspecified da,tes and near Anacapa Island on November 20, 1907. Willett (Pac. Coast Avif. No. 21, 1933:16) states that the Black Petrel “during the winter season feeds commonly on garbage off San Pedro.” But I wonder if perhaps the date of September 30 might not have provided the basis for the assumption of winter occurrence, for it was on this date in 1928 that Willett and Loye Miller found the species in abundance off San Pedro a.nd collected a number of specimens.
The latest definite dates for California waters which I can find in collections, literature. notes. or by correspondence, are September 18 for Monterey Bay (Museum of Vertebrate Zoology toll.) and September 30 for southern California (Los Angeles Museum and Loye Miller colls.). Further, Laurence Huey, Loye Miller, and the writer, all of whom are fairly familiar with the ocean off southern California, have never seen the species there at any time in the winter months. The earliest spring records are April 21, on which date in 18% on Los Coronados Islands, Anthony (Auk, 15, 1898:141) found Black Petrels. Huey collected a specimen on the same islands and date in 1929. Anthony reported incubating birds on Los Coronados as “late as September 8,” but there is no certainty that the young of such late nestings are brought to maturity.
Present evidence points to the winter range of this petrel as being in tropical and semitropical seas from the head of the Gulf of California, where its occurrence is possibly sporadic or irregular (van Rossem, Oct. Papers Louisiana State Univ. No. 21, 1945:30), south to about 8” south latitude, with perhaps the most concentrated populations occurring between Panama and Peru (Murphy, Oceanic Birds South Amer., 1936:743). Intermediate stations, dates, and specific comment on the-d& tribution of the Black Petrel in Baja California, and the Gulf of California will be offered later. The present note is designed to solicit definite information as to whether the Black Petrel winters anywhere along the Pacific coast of California and Baja California.-A. J. VAN ROG~EM, Dickey Collections, Univerdy of California, Los Amgeles, November 9, 1946.