Transcript:
A MARTÍNEZ, HOST:
Raptors, such as hawks and falcons, are masters of the air, effortlessly navigating the skies. New research looks at how these birds compensate for lost feathers and provide insights that may inform aircraft design. Here’s NPR’s Ari Daniel.
ARI DANIEL, BYLINE: Alfonso Martinez-Carmena spent his summer vacations growing up visiting the wild areas of northern Spain, gazing upwards at a range of birds of prey.
ALFONSO MARTINEZ-CARMENA: You got, like, kestrels, and then you have the big size black vultures, even golden eagles.
DANIEL: He’d admire the birds for hours through his binoculars, watching them glide smoothly through the air, imagining the views.
MARTINEZ-CARMENA: You wonder what the views would be being that bird when you were a kid.
DANIEL: The raptors later inspired Martinez-Carmena to pursue his Ph.D. in aerospace engineering. But when he went on to become a researcher at UC Davis, he found his way back to the birds, eager to understand a raptor’s mastery of flight, even as it molts and loses its feathers.
MARTINEZ-CARMENA: With time, feathers may get damaged. So they may have gaps in their wings, in their tails.
DANIEL: These gaps alter the aerodynamics of the birds, yet they’re clearly still able to fly. And Martinez-Carmena wanted to know…
MARTINEZ-CARMENA: How are they doing it? What can we learn from them?
DANIEL: He teamed up with the California Raptor Center at the university to work with Jack, a majestic 14-year-old red-tailed hawk.
MARTINEZ-CARMENA: It’s a very, I would say, like, patient bird. From the very beginning, I think he behaved really well at my presence.
DANIEL: Martinez-Carmena installed four high-speed cameras to record Jack in the summer as he was molting and again in the winter, once he regrew all his feathers.
MARTINEZ-CARMENA: We wanted to reproduce the 3D trajectory of the bird, so looking at the tail, looking at the wings, different points.
DANIEL: He and his colleagues were interested in how Jack managed to fly between perches, an especially athletic aerial maneuver.
MARTINEZ-CARMENA: In which the bird approaches the target, and it has to slow down from whatever speed they were flying at to almost zero and precisely land.
DANIEL: The analysis revealed that Jack subtly altered his body to accommodate the missing feathers by positioning his wings closer together during a portion of each wing beat and angling his tail farther downwards just after taking off, allowing the hawk to perch successfully over and over, even while molting.
MARTINEZ-CARMENA: Understanding, like, how birds adjust their flight may help rehab centers to tailor specific exercises to strengthen those muscles.
DANIEL: There may be broader engineering lessons as well that could inspire alternative aircraft designs or suggest how an aircraft might compensate if it were to become physically compromised. The research is published in the Royal Society publishing journal.
LYDIA FRANCE: I really love this kind of work because you not only have to be really good at flight when you’re in tiptop condition, but you also have to be able to fly when there’s things wrong with you.
DANIEL: Lydia France is a flight biologist at the University of Oxford who wasn’t involved in the study. For her, the main limitation is the work’s based on a single bird, but she says it’s an important starting point and that molting is just one difficulty a bird may face when flying.
FRANCE: They might get wet from the rain. That adds a lot of weight. There may be mud splattered on them. The females may have eggs inside.
DANIEL: So it behooves birds like Jack to be able to flex their flying behavior, accommodating a forever shifting set of variables to stay aloft.
Ari Daniel, NPR News.
(SOUNDBITE OF HAWKTAIL’S “IN THE KITCHEN”)