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Fly Now; Swim Later

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Illustra’s documentary Flight: The Genius of Birds came out two years ago, but the team behind the film has not been idle in the meantime. More about their latest project in a minute. First, here are several new discoveries that advance the argument for design in birds.

The Alula

There’s an animation in Flight about the alula, a bone with specialized feathers on the leading edge of the bird’s wing. This structure “alters the flow of turbulent air over the wing,” providing for a controlled descent and smooth landing. A shot of Canada geese landing on a lake demonstrates it in action. What exactly does the alula do to the air flow?

New details about the alula have come to light, thanks to researchers at Seoul University. EurekAlert announces, “One mystery of birds’ flight is solved!” That mystery is why the alula comes into play during steep descents and landings. “Why do they use it? How can the tiny feathers help them land softly?” the researchers wanted to know. Of interest is the fact that the alula is not essential; birds can land without it. But with it, they seem to be able to turn more easily.

Experiments in wind tunnels showed that the alula of a magpie wing creates a tiny vortex that presses the airflow closer to the wing. This improves flight aerodynamics, giving the bird better control for sharp turns and steep descents. It’s the first time researchers have found evidence that “the effect of the alula is due to a small vortex formed at the tip of the alula feathers.”

Design is the hero of this discovery:

Nature is full of vortices, and the animals and plants use them wisely. The role of the alula in avian flight is just one example.” says Dr. Haecheon Choi, the corresponding author of the paper. The authors aim to apply the way that the alula works in designing a device that enables the air vehicles to turn better and more efficiently. [Emphasis added.]


One of the unforgettable episodes in Flight is the segment on starling murmurations: enormous flocks that move and turn like a giant organism in the sky. The film presents a theory about topological distance that came from research in Rome that monitored the positions of individual birds using a 3D model. “It’s a bit like fighter pilots… who monitor the position of their nearest neighbor,” Dylan Winter says. The narrator admits, though, that this idea only offers a “partial explanation” for the ability of half a million birds to turn rapidly and gracefully without colliding.

The Roman research team mentioned in the film has continued work on the problem. At PhysOrg, Bob Yirka reports that they are now using wave theory to try to explain the properties of the flock. This new approach also explains flock size. Rome’s starlings have become “the stuff of legend,” Yirka says, “thanks to tourism and movies” (Flight, perhaps?).

Here is how researchers are making use of wave theory:

Prior research has found that the birds alter the distance between themselves and others around them based on distance awareness — the result is a flock that moves in ways similar to sound waves. In this new effort, the researchers wanted to better understand flying direction in the flock — what causes it to come about and in what ways does it occur? To find out, they created a 3D model using datasets from real starling flocks, allowing for creating flocks of any size. Suspecting that directional flying might be related to flock size, the researches created different sized flocks that fell into three main categories: large, intermediate and small.

In looking at their model simulations, the researchers noted that those flocks intermediate in size tended to be too small for the spread of density waves, yet were too large for directional changes to spread throughout the flock, which they noted, likely accounts for the absence of such flocks in the real world. Flocks that number in the tens of thousands, the team notes, can continue to exist despite subsets of birds tending to fly in their own direction for a moment or two — resulting in what they team calls soft edges. Smaller flocks on the other hard are far less flexible — they maintain a consistent shape when traveling, because, the researchers suggest, information is able to travel to all the members relatively quickly.

Starlings do the wave. That’s cool enough. It seems, though, that this is still only a partial explanation. “But that’s OK,” Dylan Winter would repeat from his lines in the film: “Because every time I come out here, I’ll still be amazed, and I’ll walk home thinking, ‘How wonderful is that!'”


There was only a fleeting shot of a woodpecker in Flight, but woodpeckers could warrant a documentary of their own. Students at McMaster University put together an infographic that explains “Why woodpeckers don’t get headaches.” Posted at PhysOrg, the diagram makes a good case for irreducible complexity: four cooperative and independent adaptations in the woodpecker’s skull, brain, eyes, and hyoid bone are minimally required to turn the bird into a hammer-headed bug-hunter. This description is insightful: “A third eyelid helps keep the eye from popping right out of the woodpecker’s head.”

Prepare to Take the Plunge

So what have the Illustra wizards been up to lately? If you liked Flight and Metamorphosis, you’re going to love the third installment in Illustra’s “Design of Life” series. It’s Living Waters: Intelligent Design in the Oceans of the Earth.

The crew is just now assembling the final cut, and expects to start duplication onto DVD and Blu-ray in the second half of June. Suffice to say, the cinematography, animations, music, and science sets a new high mark for excellence in Illustra’s documentaries, and is sure to give Darwinians headaches. You can see the trailer here:

If you’re in the Seattle area, there’s a premiere event scheduled for August 7.

Image: Starling murmuration, by Walter Baxter [CC BY-SA 2.0], via Wikimedia Commons.

Evolution News

Evolution News & Science Today (EN) provides original reporting and analysis about evolution, neuroscience, bioethics, intelligent design and other science-related issues, including breaking news about scientific research. It also covers the impact of science on culture and conflicts over free speech and academic freedom in science. Finally, it fact-checks and critiques media coverage of scientific issues.



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