Can birds read? While a new study provides evidence of avian intelligence, no, our feathered friends aren’t literate (as far as we know).

Canadian researchers, working in France, have found that birds foraging on roads and highways vary the amount of time they take to leave the asphalt when they see a car approaching. And it appears to depend on the posted speed limit.

During Pierre Legagneux’s commute he noticed that birds let him drive closer if he was traveling on a slower road. Using a modern, hi-tech tool—a stopwatch—the scientist monitored the birds’ “flight initiation distances” (FIDs) from the safety of his speeding car.

“FID is basically the distance that the car is from the bird when the bird takes off,” explains Academy bird expert Jack Dumbacher. “When a car is moving slowly, the bird can wait until the car gets pretty close, but when the car is moving fast, it has to begin taking off when the car is still very far away—just to make sure that it can avoid being hit. He was able to measure this pretty easily on his commute by multiplying his speed by the time it took to reach the bird.”

Over a year’s time, Legagneaux measured the FIDs of 134 birds from 21 different species, including many crows (Corvus corone), sparrows (Passer domesticus), blackbirds (Turdus merula) and unidentified songbirds.

And what he found was astonishing! His actual speed had nothing to do with the FID. But the posted speed limit did. The birds’ FID was consistently farther away for faster roads. For roads with a 20 kilometers per hour posted sign, the birds’ FID was 10 meters; 90km/hour signs, 25 meters; and 110km/hour, 75 meters.

“The authors aren’t exactly sure how the birds know, but it appears to have more to do with the AREA than with the oncoming car,” Dumbacher says. “The birds are not assessing the speed of the car, but what speed they THINK the car OUGHT to be going in that area.  And thus, the best predictor in the models was the actual posted speed limit.

“The method is simple and elegant—and something that he was able to do while commuting and paying attention to traffic. (Apparently there aren’t laws against operating a stopwatch while driving in Europe.),” Dumbacher continues.  “All he had to do was jot down 1) his speed, 2) the speed limit, and 3) the time it took to reach the spot where the bird took off.  From his citations, it looks like something like this has been studied before, but this is a cool and interesting article—something that a high school student could do for her science fair project (if she were old enough to drive…).”

The research is published in Biology Letters.

Crow image: Mostly Dans/Flickr

With their short wings relative to body size, hummingbirds are built for hovering. Their relatives, swifts, have super-long wings, built for gliding and high-speed flight. Their common ancestor, Eocypselus rowei, had wings sized between the two and they were built for… well, it’s hard to say.

“[Based on its wing shape] it probably wasn’t a hoverer like a hummingbird, and it probably wasn’t as efficient at fast flight as a swift,” says Daniel Ksepka of the National Evolutionary Synthesis Center.

Ksepka and his colleagues discovered a fossil of E. rowei in southwestern Wyoming at a fossil site known as the Green River Formation. The small bird—only twelve centimeters from head to tail—lived about 50 million years ago. Feathers account for more than half of the bird’s total wing length.

The researchers compared the specimen to extinct and modern day species. Their analyses suggest that the bird was an evolutionary precursor to the group that includes today’s swifts and hummingbirds. “This fossil bird represents the closest we’ve gotten to the point where swifts and hummingbirds went their separate ways,” says Ksepka.

Their study was published last week in the Proceedings of the Royal Society B.

The shape of the E. rowei’s wings, coupled with its tiny size, suggest that the ancestors of today’s swifts and hummingbirds got small before each group’s unique flight behavior came to be. “Hummingbirds came from small-bodied ancestors, but the ability to hover didn’t come to be until later,” Ksepka explains.

Closer study of the feathers under a scanning electron microscope revealed that carbon residues in the fossils—once thought to be traces of bacteria that fed on feathers—are fossilized melanosomes, tiny cell structures containing melanin pigments that give birds and other animals their color. The findings suggest that the ancient bird was probably black and may have had a glossy or iridescent sheen, like swifts living today. Based on its beak shape it probably ate insects, the researchers say.

Hummingbirds and swifts are two of many animals built for speed. Later this week, the Academy will open a new exhibit called Built for Speed, that will feature fast fishes and marine mammals. Learn more here.

Image: Mdf/Wikipedia