In biology, we're always trying to find newer and better ways to study animal behavior. Since the 1960s, researchers have studied bird behavior by hand crafting fake eggs. However, this process can be difficult and time consuming, especially when you want to study these birds in large populations. When we went to the museum, we learned about cowbirds. These birds lay their eggs in the nest of other species; sometimes they get tossed out, sometimes they get accepted. Scientists are trying to understand what characteristics of the eggs make the difference. Is it size? The presence or lack of speckles? The color? In this NPR story, Mark Hauber of Hunter College in New York talks about his difficulties in making the traditional plaster eggs, and how new and very available 3-D printing technology has allowed for quick, easy, and consistent creation of these eggs. There are still more steps to take in order to make these fake eggs even more realistic, such as making the shell thinner, but solutions are on the horizon.