Transcriber: Quang Huy Bui Reviewer: Amanda Zhu
Hi, I’m Scott Weidensaul.
And as both a writer and a researcher,
I’ve been fascinated all my life by bird migration.
Migratory birds, which for eons, have stitched the world together
into a single unified whole through the act of global flight,
are threatened as never before.
We’ve long known that migration
is the most dangerous part of a birds annual cycle,
but now, on top of natural hazards like storms and exhaustion,
we’ve added man-made challenges,
from habitat loss
to collisions with lighted skyscrapers and communication towers,
insecticides that sicken them directly or rob them of the food they need,
even free roaming cats,
which kill billions every year in the United States alone.
Now, climate change is altering the timing of the seasons,
the wind and weather patterns on which birds depend
to get from one place to the other
and the once reliable food supplies that they need.
In North America, we’ve lost a third of our birds,
some three billion individuals,
just since 1970,
with the heaviest losses among grassland birds
like meadowlarks and bobolinks,
woodland songbirds like thrushes and warblers
and high flying insect eaters, birds like swallows and swifts.
So the news can sound pretty grim,
but at least we know what we’re up against,
and there’s a lot that all of us can do in our day to day lives
to make a demonstrable difference for migratory birds.
And ironically,
this recognition of their peril is coming
just as we are beginning to understand how truly incredible migratory birds are:
the astonishing physical feats they perform
and the amazing ways
in which they have adapted to a life of almost constant travel.
For example,
little ruby-throated hummingbirds that weigh slightly more than a penny,
beating their wings 60 times a second for 24 hours at a stretch,
fly 600 miles, nonstop, across the Gulf of Mexico.
And they do it twice a year.
Little semipalmated sandpipers,
barely six inches long and weighing less than an ounce,
will take off from the coast of Nova Scotia
and fly 3,300 miles, nonstop, across the western Atlantic
all the way to the northeastern coast of South America.
That’s a journey of four or five days of continuous, nonstop power flight.
It’s the equivalent of a person running 126 consecutive marathons.
And they do it all on a couple of grams of fat
hidden under their skin.
Although they burn that fat with such efficiency
that if they were using gasoline instead,
they would get 720,000 miles to the gallon.
Every time we think we know
what the physical limits of bird migration are,
the birds blow right past them.
Arctic terns from the coast of Maine travel 51,000 miles every year
to spend the winter in the Indian Ocean.
In California, every summer,
there are shearwaters that were born in Tasmania and New Zealand,
along with albatrosses from Hawaii and Japan,
and storm petrels from Antarctica.
Some birds have cut their ties to the ground almost entirely.
In recent years, scientists using tiny little tracking devices
with built-in accelerometers
were shocked to find that some species of swifts,
once they leave their breeding grounds in Europe for Africa,
spend up to 10 months in continuous flight.
Now, obviously, if a bird is going to spend weeks or months on the wing,
it has to figure out some way to sleep.
And migratory birds do this
by putting alternating halves of their brain to rest
a few seconds at a time.
It’s called “unihemispheric sleep.”
And not only does it allow them to avoid the effects of sleep deprivation,
they actually experience an increase in reaction time and reflex.
Migratory birds can reorder and reshuffle their internal organs,
growing and jettisoning aspects of their internal anatomy as needed.
For example, bar-tailed godwits,
which are a pigeon-sized shorebird with a long, skinny ice pick bill.
They have the longest nonstop migration of any landbird on Earth,
an 11-day, 7,700-mile flight across the widest part of the Pacific,
from Alaska to New Zealand and the coast of Australia.
To do that, before they take off,
they more than double their weight so they have 55% fat.
And then, because they no longer need their digestive system,
they get rid of it.
In a matter of days, their stomach, intestines and other internal organs
shrink dramatically
while at the same time, their breast muscles and heart muscle
increase by 50 percent.
And they do this all without exercise.
Then they take off, make the flight to New Zealand,
regrow their guts and start to eat again.
Researchers have recently found
that one of the most bizarre aspects of quantum physics,
which may eventually enable unhackable computers
at faster than light communication,
what’s known as quantum entanglement,
is already at work in the eye of a migratory bird,
allowing it to visualize the Earth’s magnetic field
and find its way through the night sky
when most of these birds are migrating.
The only way to save migratory birds is to understand them.
And perhaps, just in the nick of time,
we’re developing the tools and technologies we need
to peel back the mysteries of where these birds are going
and follow their movements with detail and intimacy.
Researchers are harnessing the power of the Doppler weather radar network,
which almost by accident
does more than just track thunderstorms and snowfall.
It allows us to tally, with extraordinary accuracy
and on a minute-to-minute basis,
exactly how many birds are in the night sky, migrating.
On many nights in the spring across the United States,
that's more than half a billion birds at a time.
And because we have archived weather radar data
stretching back decades
and enough raw computing power now to crunch all of that information,
we can basically look back in time
and see exactly where and when migration has changed in North America.
That’s one reason that we know we’ve lost nearly three billion birds
in the last 50 years.
Advances in miniaturized transmitters and data loggers
are allowing us now to follow even the smallest migrants,
like warblers and hummingbirds, across landscapes.
This is something that I’ve been directly involved in in my own research,
and it is a stunning experience -
to recapture a thrush that we tagged the previous summer
in the wilderness of Central, Alaska,
download the information in its data logger
and watch its precise route spool out on the map,
8,000 miles to the forests of northern Argentina and back.
That is both amazing and deeply, deeply humbling.
And with this new knowledge
comes the power to change things for the better for migratory birds,
to recognize previously unknown threats,
to identify critical habitats and locations to protect,
and to take actions
to start to reverse the declines that we’ve been seeing.
For example, scientists with the Nature Conservancy
in California’s Central Valley
combined information from eBird,
a massive bird observation database
that grows by a 100 million sightings a year,
along with high-resolution satellite imagery from NASA
that allowed them to pinpoint
exactly where and when to pay farmers relatively small amounts of money
to flood their rice fields,
just enough water at just the right time
to create tens of thousands of acres of so-called pop-up wetlands
that are superb habitat for migratory shorebirds
and at a bargain price.
The challenges facing migratory birds today can seem overwhelming,
and some of them, like climate change,
are going to require global efforts to overcome.
But we don’t have to wait for big systemic changes.
There’s plenty that we can all do in our day-to-day lives
that can make a demonstrable difference for migratory birds.
For example, whether you have a tiny little yard in the city
or a lot of land in the country,
devote at least part of your property to native plants,
especially native fruit-bearing shrubs.
Unlike exotics from distant parts of the world,
natives are pre-adapted to your climate,
they require little maintenance,
and when you plant them,
you’re binding together broken ecological connections.
Even a small patch of native plants multiplied across millions of backyards
can make a huge difference for migratory birds.
Because birds, even day-active birds, migrate primarily at night
and because they navigate, at least in part by starlight,
birds are drawn into urban areas by light pollution.
Encourage your city leaders to adopt “lights out” measures
during the couple of weeks in the spring and fall
when the bulk of the migration is passing through your area,
dimming office tower and skyscraper lights to avoid fatal bird collisions.
And because birds are drawn into urban areas by light pollution,
urban green spaces like parks can provide a life raft
for millions of birds every year in North America.
So encourage your city to manage parks for birds
as well as for human recreation.
It’s not hard to find room for both.
OK, this one is really simple.
If you have a cat, please keep it in the house.
According to the Smithsonian Migratory Bird Center at the National Zoo,
cats killed between two billion and four billion birds every year
in the United States alone.
There are a lot of causes of human-related bird mortality,
from window collisions to insecticides,
all of them cumulative,
all of them on top of the natural hazards of migration.
Cats ought to be the simplest and easiest of these to solve.
And staying inside is safer and healthier, and better for the cat as well.
Take part in community science projects,
which give conservationists the information they need
to manage and restore bird populations.
The simplest way to do this,
whether you’re a hardcore birder or a backyard enthusiast,
is to log all of your sightings into eBird at the Cornell Lab of Ornithology.
eBird is now the largest wildlife database in the world,
thanks to tens of millions of birders who add their sightings every month,
giving us an extraordinary overview of exactly what species of birds
are where, when,
and in whatever changing numbers.
Finally, if you enjoy a cup of coffee every day,
seek out and buy certified shade-grown coffee,
particularly bird-friendly USDA organic coffee,
certified by the Smithsonian Migratory Bird Center.
Why coffee?
Because the way coffee was raised traditionally
in Latin America and the Caribbean,
grown deep in the shade of intact, functioning, biodiverse forests,
not only provided a valuable crop for farmers,
it provides great habitat
for hundreds of species of migratory birds.
Today, we've lost about 40 percent of those shade coffee farms,
replaced by inexpensive, sun-tolerant, chemically dependent coffee
grown primarily for the American market.
But in places where farmers are earning a premium price
for their certified coffee,
many of them are replanting denuded land,
creating new tropical forests for coffee -
but also for birds.
But it’s important that you look for certified shade-grown coffee.
Just because it’s fair trade organic
does not mean it came from a farm that’s managed well for birds.
And unfortunately, a lot of coffee that is sold as shade-grown is not.
Look for that Smithsonian Bird Friendly certification to be sure.
For eons, migratory birds
have surmounted the challenges of distance, time and physiology
to wrap the world in movement.
Their strength and stamina have always been enough,
but not anymore.
Now their fate lies in our hands.
It’s not too much to ask
that we pay attention to what we put in our coffee mugs
or what we plant in our gardens
If in doing so,
we can help smooth their passage and ensure their future.
Thanks.