R.S. Brown 1963 Great Frigatebird McKean Island 24 Oct. The preceding samples were collected at about 1200. Many of the animals were exceedingly fresh and thus, the birds are being fed throughout the day. The percentage of fish to squid are arrived at by visual determination, which is a bit crude, but 1000% better than nothing. Attempts to separate out the fish from squid and weigh each separately largely fails because after the two components are no intermixed that large error is obtained at any rate. In testing my ability to visually estimate the percentage of each food type, I find in a few samples which were clean eet and easily separated & weighed individually that I come to within 5% of the actual percentages - thus for these for this type of determination, I feel that the results are acceptable. The systemic variation presented in the differing samples does not justify any attempt at finer distinction at any rate. This probably because the birds are feeding on an opportunistic basis for the most part. The Frigate's regurgitation samples (both species) contain squid and beam- birds of larger dimension in most cases than the specimen of the same size found in stern samples. Thus it would appear that the frigate are either guaranteeing both or are feeding for themselves. The frigate samples of both species were collected in open north sheltered bays and inspected I often everything since they could not be greatly scaled with alcohol in them.