New Research Reveals Diet of Baby Eastern Bluebirds

In this episode of the Backyard Ecology podcast, host Shannon Tromboli interviews entomologist Ashley Kennedy about her groundbreaking research on the diet of Eastern bluebird nestlings. Using GoPro cameras set to take one photo per second, Kennedy captured over 8,000 images of prey items delivered to bluebird nests across four summers in northern Delaware. Her study revealed that caterpillars (Lepidoptera) made up 35–40% of the diet—primarily smooth, green, camouflaged species—followed by orthopterans like crickets and grasshoppers, and spiders, especially larger wolf spiders. The research also uncovered surprising foraging behaviors, including bluebirds consuming frogs, baby snakes mistaken for worms, and even immature dragonflies during their brief emergence from water. Kennedy’s follow-up preference study showed bluebirds strongly favored waxworms over other insects, though cabbage loopers were less appealing due to rapid decomposition in the sun. The episode emphasizes that while bluebirds are excellent subjects for non-invasive research due to their habit of landing on nest box roofs, findings may not generalize to other cavity-nesting birds. The research has direct implications for backyard conservation, highlighting the importance of native plants that support caterpillar populations. The episode concludes with a call to action for listeners to support the podcast through small monthly donations, likening it to the cost of a soda. Kennedy’s work underscores the value of backyard ecology and the power of accessible technology to reveal hidden aspects of wildlife behavior. The next episode will focus on practical steps individuals can take to support bluebirds based on this research. The tone is enthusiastic, educational, and empowering, celebrating the intersection of citizen science, technology, and conservation.