Given worldwide concern about a decline in student engagement in school science and an increasing call for science for citizenship in New Zealand Curriculum, this study focused on a butterfly unit that investigated how students in a year-4 primary classroom learnt about New Zealand butterflies through thinking, talking, and acting as citizen scientists. The butterfly unit included five lessons. The researchers observed the lessons and interviewed students and the classroom teacher. The students completed a unit evaluation survey after the unit. Findings indicate that the students enjoyed and were interested in activities such as reading about butterflies, learning and using new vocabulary, drawing butterfly life cycles, as well as hunting, tagging and releasing butterflies and publishing the data they had collected on a dedicated website. Through their participation in the unit, students had opportunities to act locally and globally, and to "see themselves" in science through "being there" experience. Units like this have the potential to develop students' interest for longer-term engagement in science, even those students who may never envision themselves as professional scientists.