Life as a field biologist often involves doing some arts and crafts. Now, instead of using plaster and paint to create the models for their experiments, biologists can turn the task over to 3D printers.
That is what animal behaviorist Mark Hauber of CUNY Hunter College and his colleagues did to study how birds tell the difference between their own eggs and those that parasitic bird species have snuck into their nests. Known as "brood parasites," some bird species try to pass off their parenting duties by sneakily laying their eggs in the nests of other birds.
In a study published on Tuesday, May 26, in the journal Peer J, the researchers used a MakerBot to create 3D-printed models of the parasitic eggs from detailed photos instead of time-consuming plaster versions to study how birds are able to spot imposters.
"In the past, we had to literally mix up a batch of plaster of paris, pour them into molds and wait for them to dry or bake," Hauber said in an interview. "I wanted to come up with a use for the 3D technology that allows us both to replicate the eggs that we used for the study and to share them across the world."
American robins are particularly good at picking out parasitic brown-headed cowbird eggs from their nests. Hauber and his colleagues wanted to gain a better understanding of how robins decide which egg is an imposter that should be tossed out. This required making model eggs that each resembled cowbird eggs – but were slightly different from one another – and placing them in the nests of robins. If the robins rejected eggs with a certain characteristic but not those that lacked it, then the researchers would know that the robins were paying particular attention to that feature.
3D printing is ideal for creating these sorts of variations in the models because, "it allows us to control changes to the stimulus in a fine-scale way," said Hauber.
Using their 3D-printed eggs, they determined that it is color – not size or shape – that affects a robin's decision to reject an egg.
For Hauber, what is most exciting about incorporating this technology into his work is the ability to share the materials he uses in his experiments with scientists around the world. Plaster models are very difficult to replicate precisely, but Hauber is able to share the design for his 3D-printed eggs with other scientists so that they can accurately replicate his experiments.
"I think 3D printing is going to make science more comparable across the globe and more generalizable because of that," he said.
In future studies, Hauber hopes to incorporate another gadget called the EggBot into his work. This "open-source art robot" can draw precisely on round surfaces such as eggs, allowing the researchers to add speckling or other patterns to their egg models.
As more of a pet project, Hauber has his sights set on taking advantage of the MakerBot's ability to convert photos into models and bring the 600 life-size photos of bird eggs in his new book, The Book of Eggs, into the third dimension.
"One day, when I have a lot of time, I will do it," he said.
The findings of the study are detailed in Peer J.
