The authors describe a study aimed at enhancing knowledge about amphibian species. Two classes of 3rd and 4th graders aged 9-11 years participated in the study. In addition, approximately one half of the students participated in an environmental conservation action designated to preserve migrating amphibians. During this action, students encountered living amphibians. Students who participated in the conservation action performed significantly better on achievement tests, and 4th graders performed better than 3rd graders, even when controlling for prior knowledge as a covariate, which also showed a significant influence. Pupils expressed high interest and well-being and low anger, anxiety, and boredom. Boredom and anxiety correlated negatively with residualized achievement scores. Major implications are that learning about biodiversity should (a) focus on a small number of species, (b) start in primary schools, (c) take place outdoors, and (d) be linked with classroom teaching. (Contains 2 figures and 2 tables.)