he selected 630 (447 carbonaria, 137 typica, and 46 insularia) male moths and released them into the woods. Within two days, 149 moths were recaptured, out of which carbonaria was 27.5%, typica 13%, and insularia 17%. (The total capture after release was 770, but 621 of them were non-experimental moths, i.e. not bearing the paint marks.) Thus their survival values were 5.72%, 1.48%, and 4.32% respectively. This shows that black moths had the best survival advantage in a darkened and polluted environment. Second phase To compare the conditions of predation in different environments Kettlewell planned to perform similar experiment in both polluted and clean environments. In 1954 he surveyed several woodlands including Devon and Cornwall, but found them unsuitable because of presence of some carbonaria forms, which indicated unclean environment. Finally he went to Deanend Wood in Dorset, which was well covered with lichens. He found only the white type, including 1 insularia form, indicating clean environment. In mid-June 1955 he started the experiment. He brought along 3,000 carbonaria type. After several days, he found that out the total 190 moths eaten by birds in the wild, 86% were the black type while only 14% were the white type. In his release-and-recapture experiment for 11 days, he used 799 moths, and his recapture rate was 13.7% for the white type, but only 4.7% for the black type. Immediately after completion, he headed back to Birmingham, now accompanied by the renowned ethologist Niko Tinbergen. Tinbergen was responsible for filming the experiment, particularly to verify whether or not birds were the main predators. Out of 227 moths they released, 154 were carbonaria, 64 typica, and 9 insularia. The recapture rate within two days was 82%, 16%, and 2% respectively. It was another success, with Tinbergen capturing live movie clips of birds eating the moths. Conclusion The conclusion of Kettlewell's experiment can be summarised as follows: Birds were the main predators of moth. Moth were eaten by birds selectively in both polluted and clean forests, indicating camouflage efficiency of the different varieties of moths. The more conspicuous form of moth was always less in number after recapture; i.e. the white type in Birmingham, and the black type in Dorset. In clean and lichened area, dark moths remained scarce and were rapidly eliminated because of their conspicuousness even when experimentally introduced. Criticisms Theodore David Sargent, professor of zoology at the University of Massachusetts at