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Thanksgiving Special: The Genius of Birds

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No, not that bird, much as a prime Thanksgiving turkey done right can seem like a work of genius. Did you enjoy Illustra’s Flight: The Genius of Birds? Then you’ll appreciate this material from recent science news that could easily fill up an hour or two of documentary filmmaking, once you are done with your feasting tonight.

Brain power: Watch the video from New Scientist of Figaro, a cockatoo, fashioning a tool to get a treat.

First, Figaro makes one out of wood. The scientists in Vienna thought that might be too easy, since the wood splits into a narrow strip along the grain, so they gave him cardboard instead. Figaro quickly chewed the cardboard into a similar tool he could use to poke through a hole and get the treat. Science Daily says the researchers were surprised:

‘Studying tool-making in species like the Goffin’s cockatoo, which does not make tools naturally, is especially revealing, as these birds cannot do it by following pre-programmed instructions evolved to solve this specific problem. These cockatoos, like other parrots, offer wonderful research opportunities: their intelligence is flexible and powerful, they can solve physical and logical problems, they can learn from watching the behaviour of others, they can learn about the surrounding objects by playing — and now it seems plausible that they can imagine which object would allow them to solve a new problem and go on to build it. I am sure that they will keep surprising us.‘ [Emphasis added.]

Flight endurance: You may remember from Illustra’s film the Arctic terns that fly almost nonstop from pole to pole. With the aid of geolocators again, another endurance champion was recently measured doing something astonishing: staying airborne for 10 months at a time. It’s the common swift. National Geographic says, “They feed in the air, they mate in the air, they get nest material in the air.” They must take midair naps, too, running on automatic pilot somehow. These birds are “among nature’s greatest aeronauts, superbly adapted for a life spent largely in the skies.” The research from Lund University was published in Current Biology. A report at Science Daily shares more gee-whiz facts about these birds:

Despite the high energetic costs associated with all that flight, common swifts also manage to live surprisingly long lives, contrary to popular notions about living hard and dying young. There are documented cases of common swifts living to the age of 20.

In that time, “the accumulated flight distance equals seven round-trip journeys to the moon,” Hedenström says. And that, he says, means there are many more intriguing questions to ask and answer about the birds’ physiology.

Sahara crossers: Scientists outfitted thirty Great Reed Warblers with geolocators to monitor their migration from Turkey to sub-Saharan Africa. Phys.org reports that the songbirds managed to cross the Sahara desert by using a corridor that minimized their time over sand and water. Their annual route of 11,000 km is like the distance from Alaska to Chile. Like the scientists in Flight, these researchers had to recapture the birds to get the data loggers. They recovered five of the geolocators at the end of the study, enough to reconstruct the migration route.

Fat hummingbirds: Despite their tiny size, ruby-throated hummingbirds also migrate long distances, from North America to Central America. Science Daily says that they were observed to fatten up four days before leaving to fly south, bulking up about 35 to 40 percent of their body weight. How did scientists figure out a way to weigh these little guys? “Each bird had a microchip and [they] were weighed each time they landed on a balance attached to the feeder.”

High divers: There’s a short clip in Flight of a diving bird folding its wings and entering the water like an arrow. Despite their slender necks, gannets and boobies can drop from 130 feet and plunge into the water at 50 miles an hour to surprise fish. Humans trying that kind of dive would sustain serious injuries, Science Daily says.

In a new study published in the Proceedings of the National Academy of Sciences, Jung and his coworkers investigate the biomechanics of gannets’ dives. They found that the birds’ head shape, neck length and musculature, and diving speeds work in concert to ensure that the force of the water doesn’t buckle their slim necks.

The researchers also learned some things about human anatomy. “Considering the popular recreational sport of diving, we also find a diving speed limit for humans to avoid injury,” they say. In the paper, they compare us to the birds:

From a mechanics standpoint, an axial force acting on a slender body may lead to mechanical failure on the body, otherwise known as buckling. Therefore, under compressive loads, the neck is potentially the weakest part of the northern gannet due to its long and slender geometry. Still, northern gannets impact the water at up to 24 m/s without injuries…. The only reported injuries from plunge-diving occur from bird-on-bird collisions. However, for humans, diving into water at speeds greater than 26 m/s risks severe fractures in the cervical or thoracic vertebrae and speeds greater than 30 m/s risk death, regardless of impact orientation. Understanding the bird plunge-dive may further explain methods of injury prevention in human diving.

For the humans, though, they only considered feet-first dives. If a stunt diver tried it the gannet way (head-first), what would happen? “At a diving speed of 24 m/s, the compressive force that a human would experience is about 14 kN, which well exceeds a range of maximum compressive forces (0.3-17 kN) to cause neck injury.” Somehow the birds do it every day for their entire lives.

How did birds arrive at such an effective design for diving? The authors speculate, “the bird’s structure and behavior have presumably evolved to withstand a variety of high dynamic stresses, because no injuries have been reported in plunge-diving seabirds.” A lot of birds must have died of broken necks for millions of years until the right random mutations showed up.

Starling picnic: The clip in Flight about starlings has gotten over a million views on YouTube.

Now, New Scientist reports that Australian starlings host an annual party to benefit all kinds of other animals. The birds tend to roost together in the same trees in certain nesting “hotspots.” Their droppings nourish the roots and organisms in the soil, increasing insect diversity enormously. These, in turn, “pull in the highest number and diversity of species by far,” including “wallabies, bandicoots, brush turkeys, cockatoos, brown tree snakes and white-lipped tree frogs” as well as introduced species — about 42 species in all. “The continuous animal chaos around starlings’ nesting trees is nature at its glorious abundant best,” one conservationist remarks.

Beak airful: Bird beaks are better designed than scientists realized. Phys.org tells about some scientists who decided to put some beaks under a CT scanner with contrast enhancement. To their surprise, they found elaborate passageways that they think serve as air conditioners: “the insides of birds’ bills are filled with complex structures that help them meet the demands of hot climates.” The response got emotional:

“I remember the entire team assembled for the first time, huddled around a computer and looking in amazement at the first scans. The high resolution scans revealed many structures that we as experienced ornithologists had never seen or even imagined, and we were immediately struck by the beauty of the ornately structured anterior conchae and the neatly scrolled middle conchae.”

“This study highlights the remarkable complexity of the rostral conchae in songbirds. This complexity has gone largely unnoticed due to the ways in which most birds are collected and preserved,” according to Jason Bourke, a researcher from the North Carolina Museum of Natural Sciences who was not involved in the research. “Thanks to the use of innovative techniques like diceCT, we are now able to really appreciate just how complicated bird noses can be.”

These articles make it clear that our friends at Illustra only scratched the surface of avian wonders. With ten thousand species of birds in the world, the genius of birds’ designs could easily keep scientists busy for many lifetimes to come, coaxing them to look in amazement at beautiful things they had never seen or even imagined.

Photo credit: alex grichenko via Public Domain Pictures.