Flamingos, often seen standing in shallow alkaline lakes, are employing a complex feeding strategy involving their feet and beaks to create water vortices that trap prey. Researchers have documented this behavior in Chilean flamingos at the Nashville Zoo using 3D printed models of their feet and L-shaped bills.

Victor Ortega Jiménez, an assistant professor at the University of California, Berkeley, explains that flamingos use their webbed feet to stir up sediment from the lake bottom. This is followed by upward head movements that create mini tornados in the water, concentrating food like brine shrimp for easy capture. "Flamingos are actually predators," said Ortega Jiménez. "They are actively looking for animals that are moving in the water."

The study, published in the Proceedings of the National Academy of Sciences, was a collaboration between UC Berkeley, Georgia Institute of Technology, Kennesaw State University (KSU-Marietta), and the Nashville Zoo.

Ortega Jiménez notes that this behavior challenges previous assumptions about flamingos as passive filter feeders: “It seems like they are filtering just passive particles, but no.” The findings could influence designs for systems targeting microplastics or self-cleaning filters.

Filming during visits to zoos sparked Ortega Jiménez's interest in these birds' feeding habits. His research involves detailed analysis using models to understand how flamingo anatomy aids in capturing prey efficiently. He has worked across institutions such as Kennesaw State University and Georgia Tech before joining UC Berkeley.

At UC Berkeley, experiments with real flamingo beaks demonstrated how chattering increases prey capture efficiency by seven times compared to non-chattering methods.

Co-author Tien Yee used computational fluid dynamics to confirm these observations: “We observed when we put a 3D printed model in a flume...they are producing symmetrical vortices on the sides of the beak.”

Future research will explore how other parts of flamingo anatomy contribute to their unique feeding strategies. Ortega Jiménez emphasized that "flamingos are super-specialized animals for filter feeding." The study received support from several grants including those from NSF CAREER iOS-1941933 and Open Philanthropy Project.