Birds of a feather: Science provides the answer to how sandgrouse hold water in their plumage

12 Apr 2023

Image: © Alta Oosthuizen/Stock.adobe.com

Using tech, a new study found that sandgrouse feathers are structured differently from those of most birds – and that is the secret behind their abilities.

Scientists from Massachusetts University of Technology (MIT) and John Hopkins University in the US have flocked together to make an important discovery about birds and how their feathers retain water.

Materials scientists and engineers have long been fascinated by how birds’ feathers can absorb, retain and shed water as needed.

Using scientific techniques, the scientists investigated how the feathers of a sandgrouse, particularly the Namaqua sandgrouse, can hold significant volumes of water.

Their study was mostly driven by curiosity around how and why the sandgrouse carries water in its feathers.

The first instance of one of these water-carrying birds behaving in this way was recorded in 1896 by a person who was breeding the birds in captivity. EGB Meade-Waldo was the first person to write down that he saw these birds spending time dipping their belly feathers into the water for several minutes at a time and fluffing them before flying off back to their nests with water for their chicks.

After Meade-Waldo’s records, it took decades for any other scientists to make headway on the phenomenon.

Then, in 1967, Tom Cade and Gordon MacLean reported detailed observations of the sandgrouse at watering holes. Their study proved that the unique behaviour was real. The two scientists found that male sandgrouse feathers could hold about 25 millilitres of water, or about a tenth of a cup, after the bird had spent several minutes dipping and fluffing its feathers in the water.

According to the MIT and John Hopkins scientists who recently looked into the water carrying sandgrouse, Cade and MacLean were only able to get “part of the story”.

Prof Lorna Gibson, of MIT’s Materials Science and Engineering Department, said that the two men did not have the tools available to them that modern science does now.

Working off of the rough picture that had been provided to them by MacLean, Cade, Meade-Waldo and others, Gibson and her team were able to unlock the specific structural details that enable these birds’ feathers to hold water.

Gibson and her colleague from John Hopkins University, Prof Jochen Mueller, published their findings in a paper in the Journal of the Royal Society Interface.

They were able to borrow some feathers from a Namaqua sandgrouse belonging to Harvard University’s Museum of Comparative Zoology. The museum has an extensive collection of specimens of about 80pc of the world’s birds.

Using tech, the new study found that sandgrouse feathers are structured differently from those of most birds – and that is the secret behind their abilities.

Their team carried out their study using scanning electron microscopy, micro-computed tomography and video imaging.

The team’s work demonstrated that the varying stiffnesses of the different feather structure parts plays a key role in the ability of the sandgrouse to hold water.

Gibson believes that the work may have wider impacts when it comes to retaining and storing water in desert regions. Some adaptation of the sandgrouse feather structure could potentially be built into nets that are used to gather water in areas affected by drought.

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Blathnaid O’Dea was a Careers reporter at Silicon Republic until 2024.

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