plotted against distance collected from ground zero (Fig. 12), the effect of the site of collection upon the amount of activity within the organs or tissues is apparent. Meter readings were taken at each collecting site with a Juno ionization type instrument at the time the collections were made. These values for Runit, Aaraanbiru and Rigili are given in Table 5 in the Appendix. On the basis of the meter readings the activity levels in the terns from Runit and Rigili should be similar, but those of the terns from Aaraanbiru higher. true, however (Pig. 12). This was not found to be At Rigili, downwind from ground zero, there were higher average levels of activity in the terns than at either Runit or Aarsanbiru in which the levels were almost equal (Table 17b)}. The terns taken at Runit may have flown from neighboring northerly islands since, although singed, they were able to fly. The birds taken at Rigili, however, probably did not fly from islands closer to the target area, because 411] of the birds observed during the post shot collections at Rigili were singed or 111 and not inclined to fly. They would walk away or flutter with effort from the beach to the water when anyone came near. Analysis by Peeding Habit. The shore birds and rats have similar feeding habits; both subsist mainly on insects, seeds, and grasses so that a comparison of average levels of activity in diverse forms with similar feeding habits can be made. results are as follows: - To- The