Thirty years ago Japanese trains had a problem. They could travel fast but they caused sonic booms.
The answer was the bullet train. How did Japanese engineers develop it? They learned from birds.
Watch this 6+ minute video from Vox + 99% Invisible to learn how birds showed the way and follow one woman's quest to teach engineers that Nature has the answers. Our world can benefit from biomimicry.
For best results, copy birds.
Thank you to Holly Hickling for sharing this. For more cool videos, follow Vox (news site) or 99% Invisible (city design updates) on Facebook.
After most warblers have left for the winter, the yellow-rumped warblers come back to town.
Breeding across Canada and the northern U.S., yellow-rumped warblers (Setophaga coronata) spend the winter in North America as close to us as Ohio and eastern Pennsylvania, though not usually in our area. In late fall they stop by in Pittsburgh.
Yellow-rumps don't have to leave for Central or South America because they have a unique talent. Their bodies can digest wax. In winter they eat the waxy fruits of bayberry and juniper. Since bayberry is also called wax myrtle, it gave our common subspecies its name: the myrtle warbler.
On Throw Back Thursday, learn how yellow-rumped warblers get nutrition from wax in this vintage article: Anatomy: Wax Eaters.
p.s. Notice that the warbler in the Wax Eaters article is wearing bright breeding plumage in black, white and yellow . Autumn yellow-rumps are dull brown with a faint vest and a broken white eye ring. The best clue to their identity is their yellow rump.
In 2014, genome sequencing studies led by Robert W. Meredith worked to determine whether several branches of birds' ancestry lost their teeth independently (convergent evolution) or whether all birds have a common ancestor that evolved a toothless beak.
The project did full genome sequencing on 48 birds species representing nearly all modern bird orders. They then focused their study on six genes related to tooth enamel. All six genes became non-functional in a common bird ancestor around 116 million years ago. That's when birds lost their teeth.
(cropped image of Archaeopteryx model on display at Geneva natural history museum via Wikimedia Commons; click on the image to see the original. **Note that this Archaeopteryx model has accurate teeth but has other inaccurate/disputed features as described on Wikimedia Commons: "Archaeopteryx had a more round shape of its wings, the primary feathers were attached to the second finger unlike here, and these colours are now known to be wrong.")
Now's a good time to brush up on identifying peregrine falcons since they pass by hawk watches in October, especially on the coast. When you identify a peregrine you can also tell how old it is because the plumage is different in each age group: adult, juvenile, and sub-adult.
Plumage provides an exact age for two groups in October: Juveniles are first year birds, 6 months old, that hatched last spring. Sub-adults are second year birds, 18 months old, with nearly complete adult plumage.
Adults -- two or more years old -- all have the same plumage. Unfortunately you can't know an adult's exact age unless the bird is banded and you find out its provenance.
Here's what they look like:
Adult peregrines (2+ years old in October) have fresh plumage in charcoal gray and white. The photo at top shows an adult male in flight. The photo below is an adult female. Adults have:
Solid dark charcoal helmet (head)
Dark charcoal malar stripes (on face)
Clean white or slightly rosy chest and throat
Horizontal charcoal+white stripes on belly and flanks
Gray back: Male's is pale blue-gray. Female's is "muddy" gray.
Juvenile peregrines (6 months old in October) are the same size as adults but their colors are brown+cream. Juveniles have:
Variable brown helmet with some cream-colored traces (head)
Brown malar stripes (on face)
Cream colored chest that's striped all the way up to the throat
Vertical brown+cream stripes on belly and flanks
(Bonus!) Juveniles have cream-colored tips on their tails, visible as the sun shines through them in flight.
Above, a juvenile in flight. Below a juvenile shows off the vertical stripes on his chest and belly. His variable brown helmet with "eyes on the back of his head" and horizontal cream-colored line at his crown.
Sub-adults are 18 months old with nearly complete adult plumage except for a few juvenile feathers. They began to molt into adult plumage last spring at 10-12 months old. By October their few juvenile feathers are hard to see without a photograph. They are ready to breed next spring.
Below, an 18-month-old peregrine named Spirit is in rehab at Medina Raptor Center in the autumn of 2014. You can see her back is mostly gray with just a few brown feathers. Her head shows faint traces of the juvenile cream colors.
Why do birds look fat in winter and thin in the summer? Have they lost weight?
No. They're trying to stay cool.
Underneath their smooth outer feathers birds wear down coats all year long. The down keeps them especially warm when they fluff it out to hold more heat next to the skin. This fluffing makes them look fat on cold winter days.
When it's hot, they can't take off their down coats so they force hot air out of the down by compressing their outer feathers. This makes them look thin.
The cardinal on the left, above, is not the thinnest one I've ever seen. Cris Hamilton took his picture in May when the temperature was pleasant. He'll look considerably thinner this month.
It's just another way that birds cope with heat.
p.s. We think of down as white but on a northern cardinal it's black. Click here to see a northern cardinal's body feather, called a semi-plume, black at the root and red at the tip.
How do birds cope with heat? They have several obvious ways and at least one we can't see.
Like us, birds stand in the shade and bathe to cool off. They also appear to pant -- actually gular fluttering -- but their hidden cooling method is a surprise. They use the nasal conchae (pronounced KONK eye) inside their beaks.
Nasal conchae are complex structures that moderate the temperature of inhaled air and reclaim water from exhaled air. Birds that live in hot dry places would benefit from bigger, better conchae.
Raymond Danner of UNC Wilmington and his colleagues used CT scans to display the internal beak structures of two subspecies of song sparrows. The specimens were collected in Delaware and Washington, DC.
Delaware and D.C. don't seem to have different climates, but a bird of the dunes copes with a hot dry micro-climate compared to one that nests in a wooded inland park.
Indeed, as reported in Science Daily, the CT scans showed that "the conchae of the dune-dwelling sparrows had a larger surface area and were situated farther out in the bill than those of their inland relatives."
Here's a dune-dwelling song sparrow beak with elaborate air conditioning structures.
This extra internal gear means the dune-based song sparrows (Melospiza melodia atlantica) have larger beaks than their inland cousins.
I'll admit I haven't noticed the slightly larger beaks of the beach birds. Have you?
It doesn't make sense but if your wings are the right shape flapping saves energy.
Birds and airplanes must constantly overcome drag to stay aloft. One source of induced drag occurs during lift when swirls of air, called vortices, roll off the wingtips. This small plane generates a huge wingtip vortex, forcing it to burn more fuel as it flies.
Large soaring birds, such as turkey vultures, reduce drag in two ways. Their wingtip feathers form slots that break the single vortex into smaller ones (small is good!), and they turn their wingtips up as they soar.
Southwest Airlines turns up its wingtips, too, to save fuel.
But what about smaller birds that flap all the time? Are they doomed to inefficient, labor-intensive flight? A new study from Sweden says no.
Biologists at Lund University studied jackdaws (Corvus monedula), a corvid smaller than the American crow. Using mist and multiple cameras they found that the birds' slotted feathers, specifically designed for flapping flight, also break up the vortex into multiple swirls. See them rolling off the wings in the study photo at top.
Now that we know slots are efficient for both flapping and soaring, what prompted their development? The study's authors "propose the hypothesis that slotted wings evolved initially to improve performance in powered (i.e. flapping) flight."
In fact, flapping saves so much energy that author Anders Hedenström suggests, "We could potentially build more efficient drones to fly with active wingbeats. Within a ten-year period, we could see drones which have the morphology of a jackdaw."
Back in 2011 Danielle Whittaker showed that the scent in preen oil varies among dark-eyed juncos. Those who smell the best, from a junco's point of view, attract more mates. Yes, dark-eyed juncos can smell.
Many birds molt during summer's "down time" between raising their young and fall migration. At this point their feathers have worn out.
However (news to me!) female peregrine falcons choose a different time of year. They begin to molt during incubation, a convenient time to do it because they're temporarily sedentary and their mates supply their food. That's why we sometimes see a peregrine primary feather in the nest box. Who knew!