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In 1971, astronaut Alan Shepard hit the first birdie on the moon. Not literally, of course.
There’s no actual birds up there.
But that’s not what Charles Morton thought. In 1703 he published a pamphlet claiming that
the reason some birds disappeared during winter was because they were vacationing on the moon.
Really puts the “loon” in lunar…
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Throughout history, people were at a loss as to why some birds appeared out of nowhere
in the spring only to disappear again during winter, and when it came to explaining why,
their common sense flew south.
Aristotle figured that certain birds didn’t leave at all, they just changed from one type
to another. And a medieval scholar said geese began life as barnacles, while another claimed
they blossomed from trees every spring.
The poet Homer accepted the fact that cranes embarked on great journeys, but instead of
seeking warmer weather it was to battle tribes of mythical goat-riding dwarves at the ends
of the Earth. I am NOT making this up.
Fittingly, the answer to this avian enigma was delivered by a stork. Storks were, and
still are, a common sight in Europe during summer, except most don’t have spears hanging
out of their necks. After this unlucky bird was shot in Germany, for a second time mind
you, the origin of the spear was traced to sub-Saharan Africa, proving once and for all
that birds spent their winters in warmer climates. And not the moon.
Birds don’t use calendars, as far as we know, so how do they know when to take off?
By tallying observations about their environment like changes in daylight, average temperatures,
and the amount of food that there is to eat, a biological switch is triggered that tells
the bird it’s time to pack its feathery bags.
These days, scientists use technology ranging from leg bands to GPS to map their incredible
journeys.
The arctic tern takes the longest trip of any bird, covering as much as 50,000 miles
in a single year between its Arctic and Antarctic nesting grounds.
Bar-headed geese have to cross over the Himalayas on their annual journey, the highest migration
of any bird. To survive at those extreme altitudes, they’ve evolved specialized hemoglobin,
and like other birds, they have a special one-way respiratory system that keeps fresh
air running through their lungs all the time.
The great snipe is a migration speedster, covering more than 4,000 miles at speeds up
to 60 mph, while the bar-tailed godwit completes its 7,000 mile, eight-day journey across the
Pacific without stopping once, powering its trek by packing on more than half its body
mass in fat.
One of the world’s most amazing bird migrations is undertaken by one of the smallest: the
ruby-throated hummingbird. Before these petite pilots embark across the Gulf of Mexico, they
too add more than half their penny-sized body weight in fat too, and during their 600 mile
trip, they burn off a quarter of their body mass in just 20 hours! It’s hard to keep
weight on when you have to flap your wings 50 times a second.
“Flying V!”
The flying V might be hockey’s greatest formation, but it’s also a trick to fly
more efficiently. When a bird flaps its wings, it creates a rotating vortex off the wingtip.
If the bird behind is in the right place, it can get a free boost from that updraft.
What’s crazy is that birds can somehow sense where that vortex is, and they actively flap
their wings to stay in the sweet spot.
Birds are able to navigate the globe with amazing accuracy, some returning to the same
nesting spot year after year. Pigeons taken far from home, sealed in isolation chambers
cut off from light, outside air and magnetic fields, were still able to find their way
back. It’s easy to see how birds might draw a map, but what about a compass? Some birds
have been found to use the sun, and others the stars. But for many birds, they are the
compass.
Tiny iron-rich crystals were discovered in the eyes and beaks of many birds, and scientists
now suspect that these allow birds to sense, or maybe even see Earth’s magnetic field.
We may have had some bird-brained ideas about where our where birds disappear to, but thanks
to science we know the truth is as good as any myth. Maybe better. Stay curious.