Page:Condor15(6).djvu/21

 Nov., 1913 TIlE BIRDS OF SAN MARTIN ISI.ANI) 209 here in order to be through with their fanfily duties by "cormorant season", as we found very few small young. Whenever we went anywhere about the island a large band of these white pirates followed us. They were very tame and would swoop down to destroy eggs and eat young before our very faces. I was disgusted, once, in seeing a gull carry a struggling young cormorant off i)y the neck. The youngster weighed about half a pound, but the g.,dl swallowed him whole in mid-air. The last I saw of the gull, the cormorant was still kicking, in the gulfs throat. Another gull flew down near us and leisurely gcbbled up a brood of four young cormorants. The rest of the youngsters showed no fear at the fate of their brothers and sisters but sat quietly and axvaited their turn. I placed a camera, with a string attached to the shutter, on a rock near a nest of young cormorants, hoping to get a picture of a gull eating the young, but I was di- appointed, as the old cormorant returned first. Laras heermanni. Heermann Gull. Several seen about the island. lhalaeroeorax auritus albociliatus. Farallon Cormorant. Present in vast numbers. About 99 per cent of the bird population was made up of this and the following species. The Far- allon Cormorant nested farther in- land than the Brandt. Following are a few of our estimates as to the num- ber of birds present, and the amount of fish consumed each day by this colony. The island is a nfile and a half in diameter. The area is, then, 1.76 square miles. The breeding area only reaches inland a half mile on all sides; therefore there is a circle in the center, half a mile in diameter, which contains very few nests. The area of this circle is -9 square miles. Subtract this from 1.76 and we have 1.57 square miles, or the area covered by colonies. Call it Fig. 63. YOUNG CALIFORNIA BROWN PELI- CANS, ON SAN IARTIN ISLAND, LOWER CALIFORNIA. 1.5 sq. mi., roughly. There are 27,878,4oo square feet in a square mile, so that the breeding district contains, approximately, an area of 34,848.ooo square feet. In many little hollows, where the limits of a colony were bounded by rocks, we coun'..- ed the nests and then measured the area enclosed. We then meadured, roughly. the area between that colony and the next, and so on until we got several colonies. We then took the number of square feet over which we had traveled and divided it bv the number of nests seen and we found it to average about one nest to every oo square feet. There were several thouqand Brantit Cormorants, which ha}i left their nests and were standing around in droves. These we did not include in our estimate, as they were impossible to count. Allowing, then, one nest to every IOO square feet. we would hax, e 348,480 nests included in the inhabited area. Each nest represented, on an average, three young and two adults. We found two young sometimes, but also found many more nests xvith four young. Allowing three young and two adults to each nest.