In recent years, with the steady development of mobile and sensor technologies, the method of e-learning has gradually migrated to mobile learning, and even to context-aware ubiquitous learning. However, few evidence to show that all students can benefit from this new type of ubiquitous learning. This could therefore be an issue worth discussing further. Meanwhile, cognitive styles have often been regarded in much of the research as a factor which could impact learners' efficacy in the e-learning environment. Hence, a butterfly-identification learning activity was designed to lead students to identify butterflies in an authentic environment embedded with sensors and wireless technology. Based on the purpose of the study, we attempt to investigate what differences there are among the distinct cognitive styles of the learners. As the experimental results shown, field-independent learners have superior learning achievement to field-dependent learners. Thus, a proper learning activity needs to be designed for field-dependent learners once a context-aware ubiquitous learning environment is introduced.