14 10-6-63 (cont.) a sizeable number on immature boobys of Masked and Red-footed species which are in intermediate plumage stages from I Birds-of-the-Year to Adults. I hope to obtain a series from this island where Chan Robbins has done so much tagging of these species in the past. I estimate now that there are 75 pairs of Brown Boobys here, 120 pairs of Masked Booby, and 800-1200 pairs of Red-footed Boobys nesting here. I would also judge between 600 and 900 pairs of Great Frigatebirds here. 10-7-63 This has been a good day. We began early when Bill got up before seven to work his study area for the first time. I set out to mark several Brown and Masked Booby Nests and to tag any other adults which we might have missed. I set up seven study nests, two Masked Booby and five Brown Booby. One Masked nest has a new egg, and two of the Brown nests have new eggs. Tagged several more Juvenal Masked, and a couple of Browns. Then Bill spotted a largem Shearwater-like bird which I collected. I believe that this is a Giant Petrel: All blackish-grey, short necked, very robust; Adult Female, ovary 1.3 x .7 mm. with largest ovum of 2 mm. ( suggesting a S. hemisphere bird with reversed breeding cycles to N. hemisphere birds ). The bird was very fat, weighing 405 grams. Skinned it and saved a partial skeleton. In the afternoon went hunting for a few minutes and promptly bagged a Sharp-tailed Sandpiper ( Erolia ), and saw what I believe to be a Black Turnstone, and a Dunlin. The Dunlin was at quite a distance and I make this guess at the bird's identity with reservation. Then went to help Bill with the resetting of his traps and rousted out a Skylark ( Alunda ) which was then collected. This bird is the "sparrow" which we have seen for the past two days, and is probably the same species that I shot at and lost about a week ago. The two birds flew the same, acted the same, and possessed white outer tail feathers. And, before the first bird was killed I had seen two birds flying together: After shooting the first bird and losing it I saw only one. Skinned the sandpiper in the evening.