Poor nutrition in early life can have significant and long-lasting impacts to humans and persists in both developed and developing nations. Other species may also be susceptible to some of the same physiological impacts of malnutrition. While many forms of poor nutrition exist, this case study explores the effects of two, which have been studied in both humans and a species of bird: the zebra finch, Taeniopygia guttata. After learning about their effects on humans, students explore how early life calorie restriction (undernutrition) and low protein (protein energy malnutrition, PEM) impact the development of male zebra finch bird song. This case study is designed to help students use the process of science to understand the importance of food quantity and quality for healthy development. Students work collaboratively to collect and graph data, run simple statistical analyses (optional), make predictions, and analyze data to reach conclusions. The case was developed for an introductory biology course for majors, but could also be used in other undergraduate-level or high school biology courses.