The trapping behavior of carnivorous plants has attracted attention of naturalists for almost two centuries. With the most observations made in laboratories, the behavior of sundew in situ has not been studied enough. We observed Drosera leaf behavior in natural habitats with non-manipulative technique. Three leaf characteristics for two species (D. rotundifolia L. and D. anglica Huds.) from two regions (6 plants with 30 leaves) were continuously observed during 196 hours. Our observations show that changes of the leaf characteristics of two sundew species in nature are almost casual and likely only corrected by external factors such as relative air humidity and presence of fresh prey (“semi-accidental feeding”). We consider trapping leaves of the two studied Drosera species as transitional structures between active and passive fly-paper traps.