Life history trade-offs provide an opportunity for students to learn about concepts in ecology, evolutionary biology, and natural history. Here I present a simple activity that I created to help students use data from museums and online life history databases to explore the relationship between body size and reproductive ability in birds. This activity, which guides students in hypothesis development and testing, data collection, and statistical analysis, is applicable to students at the high school and undergraduate levels. In addition, although I focused on birds, this activity can also be applied to other taxa where life history data are available.