Cogswell 1948 2 Erolia alpina Nov. 25 E. shore San Francisco Bay, S.E. part of Richmond, Contra Costa Co., to Fleming Point, Alameda Co. This species by far the commonest shore bird here. Total numbers on mud flats visible from main highway were estimated at 6200 (compared to somewhat less than 4000 Least & somewhat more than 4000 Westerns). 1949 Apr. 22 - same locality : - relatively few now; those seen (5+) during 15 min. drive along highway all showed some black on belly. Apr. 23 N.W. end Bay Farm Rd., Alameda Co., Calif. - relatively few here too; all seen had black, or at least bluish, on belly & some show red back also.