Eco-literacy (knowledge of natural history, and direct observation of the natural world and the organisms it contains) is critical to a holistic understanding of biology. Many undergraduate biology students lack this knowledge and experience, often because of a lack of engagement with the environmental science curriculum. The effectiveness of service learning is well established, but few examples of service-learning projects in the context of natural history education have been published. We describe how we used best practices for the development of a field-based service-learning project in a college-level natural history course. The project was built around established learning goals and was conducted through a partnership with a local state park. Students worked in groups to conduct bird biodiversity surveys and prepared a printed birdwatching guide, which was presented to park staff. The project was linked to a series of assignments intended to maximize academic and personal growth, including a project plan, progress report, and reflection paper. Students reported increased engagement in the course curriculum and an increased sense of the relevance of the course content.