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Dead birds, fluttering their wings, soar over a college campus.
These clumsy birds are actually drones, or more precisely, drones cloaked in the skins and feathers of dead birds. The researchers gave the dead bird a name for the "rebirth" of the drone project - Phoenix.
This drone project is called "Phoenix" | Image credit: Mostafa Hassanalian
"Instead of making drones from artificial materials, we're redesigning dead birds into drones. Mostafa Hassanalian, the engineer leading the project and an associate professor of mechanical engineering at the New Mexico Institute of Technology in the United States, said.
For the past decade, Hasanarian has been working on drones. While researching the optimal fluttering frequency and the optimal wing shape of the flapping wing drone, he unwittingly entered the field of bionics, as he discovered that artificial materials could not replicate the actual flight of birds.
图片来源：Mostafa Hassanalian
"If we used artificial materials, we wouldn't be able to get the perfect flutter," Hasanarian said.
Phoenix Panni into a drone
In the process of creating these drones, no birds were harmed. The research team purchased the bird's wings online and worked with the taxidermy team to obtain a whole bird specimen. The birds used were pigeons, pheasants, hummingbirds and crows, which cost about $200 per bird.
With real bird wings, tail, head and torso, the researchers designed a drone control component to be installed inside the bird's body, and the dead bird could be "resurrected".
图片来源：Mostafa Hassanalian
In the lab, the reconstituted avian drone is tested on a flutter simulator to see how much pressure the wings can withstand and how fast the avian drone can reach when flying. After each flight test, data is added to a computer program, allowing researchers to analyze and continuously improve flight techniques to see how to keep these drones in the air longer.
After a series of tests, the researchers found that the dead bird wings were more efficient than wings made of artificial materials, and the same wing could generate force in multiple directions, while conventional drones would need different components for each force to achieve a similar effect.
图片来源：Mostafa Hassanalian
Birds have elastic ligaments between their feathers and flexible bones that can move subtly with changes in wind direction, and it is currently very difficult to design and manufacture wings with the same aerodynamic efficiency from artificial materials.
图片来源：Mostafa Hassanalian
Outside, the drone flutters its wings in Hasanarian's hands, and after being thrown into the air with the help of a human, it can fly forward. Currently, it can only fly for up to 20 minutes, and the research team says they are working on energy-saving strategies to extend the flight time.
图片来源：Mostafa Hassanalian
This Dead Bird drone is still only a prototype, but looking at it from a distance, it seems to be alive and well.
Does the color of the bird also affect flight?
Many birds are good at flapping their wings, but there are also some birds that flap their wings less frequently but are very capable of flying, such as the "master of efficient flight" Albatross, which can glide over the vast ocean for more than a thousand meters with little flapping of its wings.
Like many other seabirds, albatross wings are black on the top and white on the bottom. The black color absorbs more solar radiation, so the upper part of the wing is hotter than the lower side – the upper surface is about 10°C warmer than the lower surface.
漂泊信天翁（Diomedea exulans） | 图片来源：JJ Harrison
The air pressure is lower in the warmer areas, while the air pressure is higher when the temperature is lower under the wings, so the albatross gains additional lift, like the wings of an airplane, and it is more labor-intensive to fly. Inspired by the albatross, the researchers first tested fixed-wing drones and found that color does affect flight efficiency, and they are studying how the color and pattern of bird feathers affect the flight of ornithopters.
After the endurance is improved, these dead bird drones will also enter real flocks of birds in the wild for experiments. To better understand the formation and flight patterns of migratory bird flocks, the researchers set up a large bird cage in a university laboratory. In the birdcage, a small flock of bird drones flutter their wings in place against the wind.
它们以V形编队原地飞翔 | 图片来源：Mostafa Hassanalian
More "gregarious" when monitoring
Dead bird drones are equipped with components that also include tiny cameras, microphones, and other essential equipment that allows them to perform surveillance tasks. When the technology matures, dead bird drones can be used to better study wildlife and track deforestation and poachers.
“我看着你呢” | 图片来源：Mostafa Hassanalian
Traditional drones often pose problems when monitoring wildlife. For example, a bird frightened by a drone may abandon its nest, exposing its young to danger, and birds can sometimes attack the drone or collide with the drone during flight, resulting in injury.
More realistic and quieter bird drones are better integrated with the natural environment for closer observation. The gear parts of the Dead Bird drone would also be quieter if they had been improved. They may also be used to guide birds out of the airport and prevent bird strikes.
图片来源：Mostafa Hassanalian
Compared with traditional fixed-wing UAVs and rotary-wing UAVs, ornithopters have many advantages, such as low noise, low energy consumption, better hovering and low-speed flight capabilities, and runway sites that do not need to take off and slide.
Now that the dead bird part is used, the production of the flapping wing drone can directly save the troublesome production process of the mechanical wing. For such local materials, Hasanarian believes that they are "reverse engineering".
After that, they also plan to add legs to the birds, so that the drone can stop for a while without consuming too much power, and carry out monitoring.
There is no leg | Image credit: Mostafa Hassanalian
"The biggest challenge we face now is that we don't know how other birds will react," Hassan said. He was also not sure if the birds of prey would try to start attacking when they saw the drones.
emmm, are you sure you don't have to worry about being attacked?!
Resources:
[1] Anil Oza, R. G. B. (2023). Once a satirical conspiracy theory, bird drones could soon be a reality. NPR. Retrieved from https://www.npr.org/2026/01/01/1198916182/birds-drones-engineer-biomimetics
[2] Melnick, K. (2023). Dead birds are flying again — this time, as drones. Washington Post. Retrieved from https://www.washingtonpost.com/nation/2023/04/20/dead-birds-drones-fly-experiment
[3] Funnell, R. (2023). Are Taxidermy Drones Made Of Dead Birds The Ultimate Spies? IFLScience. Retrieved from https://www.iflscience.com/are-taxidermy-drones-made-of-dead-birds-the-ultimate-spies-69649
[4] Nalewicki, J. (2023). Taxidermy birds are being turned into drones. Livescience. Retrieved from https://www.livescience.com/animals/birds/taxidermy-birds-are-being-turned-into-drones
[5] Landymore, F. (2023). Scientists Turn Dead Birds Into Ghoulish Drones That Can Actually Fly. Futurism. Retrieved from https://futurism.com/the-byte/dead-birds-drones-that-fly
[6] Hassanalian, M. (2022, September 22). Festival of Cranes 2022-December 1 to 3, New Mexico Tech. Youtube. Retrieved from https://www.youtube.com/watch?v=cm4k9voE1EM
This article is reprinted with permission from the WeChat public account: Bring Science Home (ID: steamforkids), the author of Wanwu Magazine