1948 Erolia alpina Oct. 31 - Bay Farm Rd., Alameda, Alameda Co., Calif. 14:30 - 15:10 - as 8 of us stood on sandy point just E. of boardwalk to bay (San Leandro) shore from Doe- little Drive (E. of bridge from Alameda) a great flight of shorebirds, mostly peeps, moved up the bay toward feeding grounds at west of us now being uncovered by tide. Red- backs seem to be about the commonest species. Flock after flock swept past us, sometimes solely red-backs, but often with smaller admixture of western & least sandpipers. a guess of at least 4000 red-backs does not seem too wild, as several flocks definitely estimated at 500 - 800 each were seen. When mixed flocks of peeps finally settled to feed near us, a definite zoning of sizes was evident, tho with some overlaps: red-backed - in water or on edge of mud just exposed. western - at edge of water or on very wet mud. least - almost entirely above water, line, and usually on mud al. ready starting to dry a little. Nov. 7 - Dumbarton Bridge (E. approach), Alameda Co., Calif. This species by far the commonest shorebird along roadway - many hundred seen.