220 CALIFORNIA ACADEMY OF SCIENCES. 



exclusively of Brandt's Cormorants. Their nests were 

 crowded so closely together on the uneven surface 

 of the rock that room to place the foot was not always 

 readily found. Some of the nests were on little points of 

 rock, others in crevices, every available spot being 

 utilized. Most of the eggs had hatched. The young 

 were in different stages of growth, varying in size from 

 those just out of the shell to half- grown ones. The 

 larger left the nests when approached, and huddled to- 

 gether on the edge of the islet well above the reach of the 

 surf. There was such a complete mixing up of babies 

 that the old birds must have had some trouble in sorting; 

 them out when they returned, for immediately after I 

 landed most of the adults retreated to the water, congre- 

 gating in a great raft a short distance away. A few of 

 the bolder remained behind for awhile. Several, appar- 

 ently females, kept close by their young until I approached 

 within ten feet of them, when their courage failed and 

 they took flight, leaving the young to shift for themselves. 

 Two of the larger young birds sought refuge on an out- 

 lying rock, separated from the islet by a little channel. 

 They had apparently never been in the water before. 

 They succeeded, nevertheless, in swimming across the 

 channel and climbing up the steep sides of the rock, al- 

 though a number of times they were buried out of sight 

 by incoming waves. 



A vibratory movement of the gular sac, apparently oc- 

 casioned by fear, was noticed in a number of adults and 

 half-grown young. Most of the adults observed on the 

 rookery appeared to have lost the nuptial filaments. 



The general form of the nests was circular, except 

 where wedged in between rocks. They appeared to be 

 constructed entirely of eel grass ( Zostera).* Those con- 



*Iam indebted to Mr. H. L. Kimball, an investigator at the Hopkins 

 Seaside Laboratory, for the determination of this plant. 



