Grooves on a Bird’s Beak Help it Fly Faster

(Inside Science) -- In 1941, Swiss engineer George de Mestral took a hike with his dog and noticed several burrs stuck to his clothes and his dog’s fur. Curious what caused the tenacious grip, he looked at a burr under a microscope -- revealing simple hooks that allowed it to cling to socks, pants and yes, fur. After ten years of research and experiments, de Mestral got a patent for a new fabric fastener -- now known as Velcro.

De Mestral’s invention is just one of many cool technologies inspired by nature. Some wind turbine blades are modeled after whale fins. And new adhesives have been inspired by sticky gecko feet. And scientists are still looking at the natural world for their next new idea. Biomimicry -- it’s a field of science that takes cues from nature, and seeks solutions to our human problems by creating devices that copy some of nature’s time-tested patterns and strategies.

According to Bharat Bhushan, Ohio Eminent Scholar and the Howard D. Winbigler Professor in the Department of Mechanical and Aerospace Engineering at The Ohio State University, “The reason we look to nature is that nature has evolved itself over some 3 billion years and through evolution it has created structures and surfaces which provide unique functionality.”

Sharks have skin that helps them swim faster -- inspiring new swimsuits and materials for the bottom of boats. Geckos stick to walls with help from hundreds of thousands of hairs on the bottom of their toes -- scientists used that idea to create new adhesives. Copying the way a hummingbird hovers has helped make autonomous vehicles fly better. Now add black skimmer birds to the list. 

“Is the only bird out of some 10,000 birds which does fly fishing. It flies close to the water surface and when it sees a prey it dips the beak into water and catches the fish,” said Bhushan.

It’s the bird’s beak that sets it apart from all other American birds. The large red and black beak is knife-thin and the lower part is longer than the upper part. The bird drags its lower bill through the water to catch its prey of small fish.

But scooping up tiny fish is tricky. So, it needs to fly very fast without getting slowed down by water as it skims the surface. The secret is what’s on the bird’s beak -- tiny groovelike structures that go in the direction that fluids flow, allowing water to move efficiently over the beak. The grooves help reduce drag up to ten percent compared to a smooth, flat surface.

“Many times beak dipped into the water and when it sees a prey it needs to move very fast and that’s why nature provides that riblet-like structure on the beak,” said Bhushan.

Computer simulations show how vortices -- or swirling circular currents -- form when a smooth surface moves through a fluid, in this case water.  But add bumps to the surface and the vortices are lifted away -- which reduces drag and allows the bird to fly faster. Once again nature inspires human scientists. Learning the tricks of a unique bird with exceptional fishing skills could help researchers develop materials to improve air flow over cars and aircraft, or help oil flow through pipelines more efficiently. The wonders of nature, and science, never cease.