Welsh Journals

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RESULTS Table 1 gives the number of birds caught in South Castle and elsewhere on each night, together with the number of birds previously ringed in burrows which were recaptured for the first time. Table 1. The number of Shearwater fledglings caught each night. The figures are divided into two areas (the main part of the Neck and South Castle) and into birds captured for the first time (New) and those which had been ringed previously in burrows (RIC) NECK SOUTH CASTLE Date New R/C New R/C 22.8 64 3 0 0 23.8 26 2 31 1 24.8 47 5 0 0 25.8 118 14 31 1 26.8 100 10 20 0 27.8 152 10 31 1 28.8 126 7 47 1 29.8 137 18 76 2 30.8 87 4 55 1 31.8 282 15 71 2 5.9 100 1 55 3 7.9 119 3 51 3 11.9 24 0 17 1 1382 92 485 16 From these figures, using the calculation described above, we obtain estimates of the number of fledglings for the two areas of: South Castle 1722; rest of Neck 6361; Total 8083. By not dividing the area and using the overall totals we arrive at a figure of 8274. UISUUS5IUN The estimates of the number of fledglings on the Neck have to be compared with Corkhill's figures of 1971. Both figures are given in Table 2. Table 2. Estimates of the numbers of fledgling Shearwaters on the Neck, Skomer in 1971 and 1978. 1971 1978 Change South Castle 1587 1722 +8.5% Main 5828 6361 +9.1% Combined 7427 8274 +11% These figures would suggest a slight increase in numbers (of the order of 9-11 %) over the seven years. However, the differences are very small and it would be unwise to