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 211) ' THI CONDOR Vol. XV we figured about L8oo,ooo birds, as the population of not considered in this estimate, as their young were too hard to locate. Fig. 64. YOUNG OSPREY, SAN MARTIN ISLAND, LOWER CALIFORNIA the island. The gulls were too scattered and the nests We became very much interested in estimating the amount of fish these birds consumed per day. We noted the amount each young cormorant threw up when molested, and found on several occasions a bunch of fish as big as a man's two fists. This mass was generally composed of surf fish, smelt and sardines. I have heard of other estimates of from three to six sar- dines a day for a cormorant, so I consider a half pound of fish a day very conserv- ative. Allowing half a pound of fish a day for each of the t,8oo, ooo birds, the entire population would consume about four dred tons a day or about ten thousand tons a month ! The fishing was done in San Quentin bay, exclusively, but in that bay and in Hassler's Cove, on the island, fish were found very plentiful, and always hungry, skowing that the birds do not seriously lessen the number of fish. lhalacrocorax penicillatus. Brandt Cor- morant. Present in large numbers, though not so numerous as the last. On the uorth side the young gathered in big droves and resembled Penguins as they tried to waddle out of our way. leleeanus ealifornieua. California Brown Pelican. Nesting in considerable numbers on the southern shores. Ardea herodias. Great Blue Heron. Several pairs were breeding in a hollow on the southeast side. There were five nests containing three young each. Ilaemat0pus fraari. Frazar Oystercatcher. Several seen along the shores. Itaemat0pus baehmani. Black Oystercatcher. Fairly abundant along sheltered portions of the shores. Sev- eral found on a little lagoon on the east side. They  appeared to be breeding but no nests were found.  Iandion haliaetus carolinensis. American Osprey. There are about thirty pairs breeding on this island.  '-j, ._ We counted thirty-five nests, one containing two partly ?.r,?-,  grown young. The birds used the other nests as "look-outs." /Elueo pafineola. Barn Owl. My father flushed a lig' 65. Rocor WREte, SAN [ARTIN ISLAND, LOWER "big yellow owl" from a blow-hole in the lava on the CALIFORNIA. south side. Salpinctes obsoletus. Rock Wren. Very abundant and very tane. Were easily approached for photographic purposes.