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High-flying...
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sharp-eyed...
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00:00:14,083 --> 00:00:16,602
and deadly.
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00:00:17,776 --> 00:00:19,778
From mountaintops
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00:00:19,812 --> 00:00:21,711
to river valleys,
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00:00:21,745 --> 00:00:23,747
eagles rule the skies.
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00:00:25,473 --> 00:00:28,718
Strong enough to take
down enormous quarry,
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00:00:28,752 --> 00:00:32,066
they are the
ultimate bird of prey.
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00:00:33,861 --> 00:00:37,830
By following a family
of bald eagles...
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00:00:37,865 --> 00:00:39,108
This is our national symbol.
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These are powerful birds.
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00:00:41,282 --> 00:00:43,181
Witnessing eagles in action...
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00:00:43,215 --> 00:00:44,699
She's doing
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00:00:44,734 --> 00:00:46,494
eight, nine, ten
miles an hour... up!
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00:00:46,529 --> 00:00:48,634
And that's fast.
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00:00:48,669 --> 00:00:52,569
And by joining one man
and his feathered friend,
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00:00:52,604 --> 00:00:55,538
these icons of the air
will be put to the test...
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00:00:57,885 --> 00:01:00,267
What a girl!
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00:01:00,301 --> 00:01:01,440
That is actually
very, very impressive.
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00:01:01,475 --> 00:01:04,064
To reveal what it takes
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00:01:04,098 --> 00:01:07,619
and even what it feels like...
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00:01:07,653 --> 00:01:08,999
Wow.
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00:01:09,034 --> 00:01:11,899
We're flying with
a golden eagle.
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To be the most
powerful bird in the sky.
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00:01:17,180 --> 00:01:18,319
"Eagle Power."
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00:01:18,354 --> 00:01:21,253
Right now, on "NOVA."
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00:01:41,135 --> 00:01:44,690
It's late winter in Iowa.
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Under the most recent snowfall,
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00:01:52,457 --> 00:01:55,425
this bald eagle
is trying to protect
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00:01:55,460 --> 00:01:58,497
her most precious possessions.
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00:02:03,709 --> 00:02:08,162
These two eggs must be kept
at around 99 degrees Fahrenheit
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00:02:08,197 --> 00:02:11,131
to hatch successfully.
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00:02:13,926 --> 00:02:18,034
At night, temperatures
plummet to minus 13.
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00:02:22,694 --> 00:02:26,663
By day, it's cold enough
to freeze her eyelashes.
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00:02:28,803 --> 00:02:35,293
But she'll do whatever she
can to keep her eggs safe.
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00:02:38,330 --> 00:02:41,195
This nest has been
rigged with cameras
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00:02:41,230 --> 00:02:43,818
to reveal what it
takes for these eggs
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00:02:43,853 --> 00:02:47,374
to develop into
top aerial predators.
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00:02:57,246 --> 00:03:02,320
Bald eagles are just one of
around 70 different species
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00:03:02,354 --> 00:03:05,254
in the eagle world,
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00:03:05,288 --> 00:03:10,707
every one a mesmerizing
blend of power and beauty.
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00:03:12,744 --> 00:03:18,094
They've conquered a huge
range of habitats across the planet,
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00:03:18,128 --> 00:03:22,719
from harpy eagles in the
rain forests of South America
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00:03:22,754 --> 00:03:27,724
to Steller's sea eagles
in the icy North Pacific
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00:03:27,759 --> 00:03:32,350
and fish eagles in the
great lakes of Africa.
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00:03:33,834 --> 00:03:37,320
They live at the top
of the food chain.
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But to dominate their world,
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00:03:39,149 --> 00:03:42,636
they must overcome
three major challenges.
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00:03:44,948 --> 00:03:48,952
They have to cover
hundreds of miles on the wing,
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00:03:48,987 --> 00:03:51,714
spot their prey
at vast distances,
51
00:03:51,748 --> 00:03:55,890
and tackle the largest quarry
52
00:03:55,925 --> 00:03:58,238
of any bird species.
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00:04:00,964 --> 00:04:04,623
To reveal exactly how
eagles achieve this...
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00:04:07,108 --> 00:04:13,045
We need access
to a remarkable bird.
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00:04:21,537 --> 00:04:26,196
This is Tilly, a golden eagle
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00:04:26,231 --> 00:04:31,029
with a wingspan of
almost six-and-a-half feet.
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00:04:31,063 --> 00:04:33,169
Similar in size to a bald eagle,
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00:04:33,203 --> 00:04:37,138
golden eagles range across
much of the Northern Hemisphere,
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00:04:37,173 --> 00:04:40,625
including Asia, Europe,
and North America.
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00:04:40,659 --> 00:04:44,594
But what makes her special
is the relationship she has
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00:04:44,629 --> 00:04:46,320
with her lifelong partner,
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Lloyd Buck.
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00:04:52,740 --> 00:04:55,053
Hello!
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00:04:55,087 --> 00:04:56,330
Hello, my love.
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00:04:56,365 --> 00:04:58,953
You enjoying yourself, eh?
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00:04:58,988 --> 00:05:00,610
You're the best, ain't you?
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00:05:00,645 --> 00:05:03,579
You're a once-in-a-lifetime
bird, you are, eh?
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00:05:03,613 --> 00:05:07,272
I'll never have another
birdlike you ever, will I?
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00:05:08,515 --> 00:05:10,275
Since he was a child,
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00:05:10,310 --> 00:05:13,485
Lloyd Buck has been
obsessed with birds.
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00:05:16,143 --> 00:05:18,352
At his home in North
Somerset, England,
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00:05:18,387 --> 00:05:21,182
he has special licenses
to keep and train
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00:05:21,217 --> 00:05:24,393
many different species.
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00:05:24,427 --> 00:05:29,432
But one particular
bird stands out... Tilly.
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00:05:29,467 --> 00:05:33,609
They have been
together for 20 years
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00:05:33,643 --> 00:05:37,647
and have forged an
exceptionally close bond.
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00:05:41,513 --> 00:05:46,691
Tilly behaves as if
Lloyd is her mate for life.
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00:05:46,725 --> 00:05:50,177
Go on, go and enjoy
yourself, my love.
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00:05:50,211 --> 00:05:51,799
I wish I was you.
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00:05:51,834 --> 00:05:53,974
I wish I was you!
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00:05:55,941 --> 00:05:58,427
Thanks to Lloyd's
dedicated work with Tilly,
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00:05:58,461 --> 00:06:03,052
she acts just like a wild
eagle, but is also comfortable
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00:06:03,086 --> 00:06:06,124
around scientific
equipment and cameras.
84
00:06:06,158 --> 00:06:09,127
Their unique bond provides
a special opportunity
85
00:06:09,161 --> 00:06:13,718
to learn more about these
remarkable predators.
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00:06:13,752 --> 00:06:16,030
Eagles are such
inspirational birds.
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00:06:17,963 --> 00:06:19,068
There's so much, I think,
88
00:06:19,102 --> 00:06:21,173
that we don't
understand about them,
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00:06:21,208 --> 00:06:23,693
and that's what I'm
hoping to learn here,
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00:06:23,728 --> 00:06:25,626
a little window into her world,
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00:06:25,661 --> 00:06:27,110
into the world of eagles.
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00:06:29,458 --> 00:06:32,392
Together, Lloyd and Tilly
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00:06:32,426 --> 00:06:35,636
will take on a series
of tests that will unlock
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00:06:35,671 --> 00:06:38,812
the science of eagle power.
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00:06:46,923 --> 00:06:50,064
In Iowa, it's the
first week of April,
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00:06:50,099 --> 00:06:52,308
and the female seems restless.
97
00:06:55,380 --> 00:06:59,902
One of the chicks
is starting to hatch.
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00:07:06,218 --> 00:07:09,256
After 37 days of incubation,
99
00:07:09,290 --> 00:07:12,742
it uses a tiny egg
tooth on top of its beak
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00:07:12,777 --> 00:07:15,987
to crack the shell
in a bid for freedom.
101
00:07:41,702 --> 00:07:47,294
Three days later, it's
joined by its sibling.
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00:07:50,608 --> 00:07:53,127
Even at this young
age, they need to eat
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00:07:53,162 --> 00:07:56,130
almost half their
body weight in meat
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00:07:56,165 --> 00:07:57,373
every day.
105
00:08:00,480 --> 00:08:01,550
Thankfully,
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00:08:01,584 --> 00:08:05,726
help is on hand to
bring in fresh supplies.
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00:08:09,143 --> 00:08:11,214
This is the male,
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00:08:11,249 --> 00:08:14,114
and as with all bald eagles,
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he's about 20%
smaller than his mate.
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00:08:16,944 --> 00:08:19,326
It's thought she might be bigger
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00:08:19,360 --> 00:08:22,709
to help produce and
incubate the eggs.
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00:08:25,056 --> 00:08:28,438
Bald eagles
normally pair for life,
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00:08:28,473 --> 00:08:29,612
but the female's
previous partner
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00:08:29,647 --> 00:08:31,649
has disappeared,
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00:08:31,683 --> 00:08:34,548
so this male is new.
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00:08:36,688 --> 00:08:40,520
The breeding season
can last around ten months,
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00:08:40,554 --> 00:08:42,832
so rearing the chicks
will be a real test
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00:08:42,867 --> 00:08:45,145
of their new relationship.
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00:08:48,113 --> 00:08:51,600
The chicks' weight can
increase by a staggering 500%
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00:08:51,634 --> 00:08:54,982
in their first week.
121
00:08:55,017 --> 00:08:58,192
So the adults spend
much of the time hunting.
122
00:09:10,308 --> 00:09:14,657
Bald eagles are
masters of hunting fish.
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00:09:14,692 --> 00:09:17,867
They can make up
to 90% of their diet.
124
00:09:24,391 --> 00:09:28,015
They are able to pluck their
prey from the water surface
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00:09:28,050 --> 00:09:30,673
with incredible precision.
126
00:09:43,928 --> 00:09:49,623
But rabbits and squirrels
are also brought to the nest.
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00:09:49,658 --> 00:09:50,728
For now,
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00:09:50,762 --> 00:09:53,593
the partnership of the
mother and her mate
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00:09:53,627 --> 00:09:57,217
is providing all the
food the chicks need.
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00:10:05,087 --> 00:10:10,126
Eagles around the world
catch a huge variety of prey,
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00:10:10,161 --> 00:10:12,542
so they have a range
of hunting techniques.
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00:10:15,304 --> 00:10:19,239
In the mountains of
Oman, this Verreaux's eagle
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00:10:19,273 --> 00:10:22,829
is after a terrestrial target.
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00:10:24,071 --> 00:10:27,834
Rock hyrax.
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00:10:27,868 --> 00:10:30,630
These small mammals are
equipped with special vision:
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00:10:30,664 --> 00:10:33,563
a shield on their iris
137
00:10:33,598 --> 00:10:36,118
that cuts out glare,
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00:10:36,152 --> 00:10:40,260
helping them spot the
predator, even in bright sunlight.
139
00:10:42,193 --> 00:10:46,093
But this eagle is just a decoy.
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00:10:46,128 --> 00:10:50,719
Verreaux's eagles hunt in pairs.
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00:10:51,961 --> 00:10:54,619
One flies in plain sight,
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00:10:54,654 --> 00:10:56,621
distracting the hyrax.
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00:10:59,279 --> 00:11:03,007
While the second eagle
hugs the contours of the land,
144
00:11:03,041 --> 00:11:04,353
staying hidden...
145
00:11:06,562 --> 00:11:09,427
Until the last moment.
146
00:11:17,124 --> 00:11:18,712
Catching quarry like this
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00:11:18,747 --> 00:11:22,612
is a dangerous task.
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00:11:22,647 --> 00:11:26,444
There is no room for error.
149
00:11:29,792 --> 00:11:34,728
When eagles hunt airborne
prey, if something goes wrong,
150
00:11:34,763 --> 00:11:38,698
they have more space and
time to get out of trouble.
151
00:11:38,732 --> 00:11:43,703
They can even escape a glancing
blow with the water surface.
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00:11:43,737 --> 00:11:49,881
But when the prey is on hard
ground, it's a different story.
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00:11:49,916 --> 00:11:54,265
One wrong move could
result in a deadly collision.
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00:11:58,407 --> 00:12:01,721
Especially with
large, heavy prey.
155
00:12:05,863 --> 00:12:08,797
There is no margin for error.
156
00:12:08,831 --> 00:12:13,318
They must capture their
victim without mistake.
157
00:12:17,978 --> 00:12:23,743
So exactly how do
eagles catch prey on land?
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To find out, Lloyd
has come to Scotland
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00:12:29,369 --> 00:12:33,718
to put his golden
eagle, Tilly, to the test.
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00:12:36,169 --> 00:12:41,691
But first, he needs
something for her to hunt.
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00:12:41,726 --> 00:12:47,042
This is robo-bunny.
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00:12:49,976 --> 00:12:53,703
Designed and created
by tech wizard Chris Watts,
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with a fake fur coat
and high-speed motors,
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it can blend into
the undergrowth
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or flash across the open.
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00:13:01,263 --> 00:13:05,060
It's fitted with an
onboard 360 camera
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00:13:05,094 --> 00:13:07,338
to help capture
all of the action,
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00:13:07,372 --> 00:13:10,030
and a bit of bait to
get Tilly's attention.
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00:13:10,065 --> 00:13:12,170
Okay, she's gonna rouse.
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00:13:12,205 --> 00:13:13,896
Get ready.
171
00:13:13,931 --> 00:13:15,070
Okay, go, go,
go, go, fast, fast!
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00:13:17,313 --> 00:13:20,730
In a matter of seconds,
Tilly locks on to her target.
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00:13:22,215 --> 00:13:23,803
Ooh!
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00:13:23,837 --> 00:13:27,254
She's got him, she's done
it... thank you very much, Tilly.
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00:13:27,289 --> 00:13:29,360
Good girl.
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00:13:29,394 --> 00:13:31,949
To challenge
Tilly's hunting ability,
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00:13:31,983 --> 00:13:35,849
they repeat the test
in different conditions.
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00:13:35,884 --> 00:13:38,438
Go!
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From strong winds
and overcast skies
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00:13:42,166 --> 00:13:43,546
to bright sunlight.
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00:13:46,929 --> 00:13:51,002
But the outcome is the same.
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Tilly wins.
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00:13:56,490 --> 00:13:59,562
To reveal the secret
to her success,
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00:13:59,597 --> 00:14:02,358
the team needs to
go through the footage
185
00:14:02,393 --> 00:14:03,877
frame by frame.
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00:14:06,224 --> 00:14:10,573
First, Tilly keeps a constant
lock on robo-bunny's position.
187
00:14:13,887 --> 00:14:18,409
Next, she uses her wings
to adjust her trajectory
188
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as the wind changes
or the target moves.
189
00:14:25,450 --> 00:14:30,628
She keeps her legs tucked
in to stay aerodynamic.
190
00:14:30,662 --> 00:14:33,976
Then, just a quarter of
a second before impact,
191
00:14:34,011 --> 00:14:36,461
she swings her feet forwards
192
00:14:36,496 --> 00:14:40,534
so both eyes can see
robo-bunny and her talons.
193
00:14:40,569 --> 00:14:45,401
And she makes perfect contact.
194
00:14:47,645 --> 00:14:48,991
But there is one more element...
195
00:14:49,026 --> 00:14:50,544
Okay, get ready, Chris.
196
00:14:50,579 --> 00:14:52,615
To Tilly's hunting ability.
197
00:15:01,624 --> 00:15:05,559
Robo-bunny weighs
about 13 pounds,
198
00:15:05,594 --> 00:15:08,804
one-and-a-half
times more than Tilly.
199
00:15:15,949 --> 00:15:21,092
Remarkably, not only
can she strike robo-bunny...
200
00:15:23,267 --> 00:15:26,270
She can lift it into the air.
201
00:15:28,272 --> 00:15:34,036
She even has the strength
to pick it up with one foot...
202
00:15:34,071 --> 00:15:35,865
an amazing
achievement for a load
203
00:15:35,900 --> 00:15:41,457
weighing 150% of
her own body weight.
204
00:15:41,492 --> 00:15:43,287
Yes!
205
00:15:43,321 --> 00:15:46,255
What a girl!
206
00:15:46,290 --> 00:15:47,774
Good bird, there's a good eagle.
207
00:15:50,052 --> 00:15:51,709
Tilly's abilities have exceeded
208
00:15:51,743 --> 00:15:56,127
all of Lloyd's expectations.
209
00:15:56,162 --> 00:15:59,544
She's able to do this thanks
to the most important weapon
210
00:15:59,579 --> 00:16:01,029
for any eagle...
211
00:16:01,063 --> 00:16:04,687
talons.
212
00:16:04,722 --> 00:16:08,105
As veterinarian
Michael Jones explains.
213
00:16:08,139 --> 00:16:10,866
Eagle talons are very
well adapted for killing prey.
214
00:16:10,900 --> 00:16:13,696
Not only do you have
the strength in their feet,
215
00:16:13,731 --> 00:16:16,113
but you also have
this talon size, as well.
216
00:16:18,529 --> 00:16:20,876
The harpy eagle has
some of the largest talons
217
00:16:20,910 --> 00:16:22,395
in the world,
218
00:16:22,429 --> 00:16:26,537
measuring nearly five inches.
219
00:16:26,571 --> 00:16:28,297
The talons are largest
on digit one and digit two,
220
00:16:28,332 --> 00:16:30,955
and those are the ones
that typically hold the prey.
221
00:16:30,990 --> 00:16:34,579
Unfortunately for the prey,
because they are so powerful,
222
00:16:34,614 --> 00:16:36,167
the prey is usually
going to succumb
223
00:16:36,202 --> 00:16:38,894
to either extreme pressure,
224
00:16:38,928 --> 00:16:41,448
multiple puncture wounds
to the body and vital organs,
225
00:16:41,483 --> 00:16:42,449
or blood loss.
226
00:16:44,382 --> 00:16:48,800
To do this, eagles have
to grip with enormous force.
227
00:16:48,835 --> 00:16:50,457
But what is most impressive is,
228
00:16:50,492 --> 00:16:53,322
they can hold this
crushing pressure
229
00:16:53,357 --> 00:16:57,257
for a long time
with little effort,
230
00:16:57,292 --> 00:17:02,262
and it's all thanks to some
impressive mechanics.
231
00:17:04,368 --> 00:17:07,819
Their feet have an
in-built ratchet system.
232
00:17:10,581 --> 00:17:13,653
The tendons in
their toes are ridged,
233
00:17:13,687 --> 00:17:17,036
and so is the
tissue around them.
234
00:17:17,070 --> 00:17:20,004
This creates a simple
locking mechanism,
235
00:17:20,039 --> 00:17:22,800
so the surrounding
muscles can relax
236
00:17:22,834 --> 00:17:27,080
without losing any grip force.
237
00:17:27,115 --> 00:17:29,876
Many bird species
have this adaptation,
238
00:17:29,910 --> 00:17:30,877
but in eagles,
239
00:17:30,911 --> 00:17:34,018
the ridges are
particularly large
240
00:17:34,053 --> 00:17:36,952
to cope with the enormous power.
241
00:17:39,955 --> 00:17:43,441
Creating and maintaining
such a high force
242
00:17:43,476 --> 00:17:46,237
is a critical part of
an eagle's armory.
243
00:17:49,413 --> 00:17:53,831
And it helps them hunt
even the largest prey.
244
00:17:57,179 --> 00:18:01,045
But these super-strong weapons
245
00:18:01,080 --> 00:18:04,359
have a second,
essential, purpose:
246
00:18:04,393 --> 00:18:06,602
to fight.
247
00:18:15,128 --> 00:18:19,857
Winter in the Alps
is desperately bleak.
248
00:18:19,891 --> 00:18:25,518
Golden eagles soar above the
snowy peaks in search of prey,
249
00:18:25,552 --> 00:18:27,278
but food is so scarce here,
250
00:18:27,313 --> 00:18:30,592
they frequently
turn to scavenging.
251
00:18:41,603 --> 00:18:45,089
A dead fox.
252
00:18:45,124 --> 00:18:48,644
It could support this
female eagle for days.
253
00:18:50,198 --> 00:18:52,338
Such a prized meal is in demand,
254
00:18:52,372 --> 00:18:55,030
and a devious mob of
crows will try anything
255
00:18:55,064 --> 00:18:58,102
to steal a mouthful.
256
00:19:01,243 --> 00:19:03,866
A flash of talons seems
enough to remind them
257
00:19:03,901 --> 00:19:06,214
who's at the top
of the food chain.
258
00:19:14,049 --> 00:19:18,329
But these annoying crows
are the least of her worries.
259
00:19:18,364 --> 00:19:22,057
The biggest threat
comes from her own kind.
260
00:19:51,500 --> 00:19:56,333
A meal like this attracts
eagles from miles around,
261
00:19:56,367 --> 00:19:59,474
and, if needed, they'll
fight for the food.
262
00:19:59,508 --> 00:20:05,204
In battle, talons are
their weapons of choice.
263
00:20:05,238 --> 00:20:08,137
They use their long
legs to keep their head,
264
00:20:08,172 --> 00:20:09,760
and, importantly, their eyes,
265
00:20:09,794 --> 00:20:12,659
away from danger.
266
00:20:15,179 --> 00:20:17,975
They must fight to survive.
267
00:20:37,512 --> 00:20:38,685
In Iowa...
268
00:20:41,378 --> 00:20:46,279
Our bald eagle youngsters are
now one-and-a-half weeks old,
269
00:20:46,314 --> 00:20:48,108
and still defenseless.
270
00:20:48,143 --> 00:20:52,389
Even the slightest
thing can pose a threat.
271
00:20:56,496 --> 00:21:01,536
Somehow, one has become
tangled in the female's feathers,
272
00:21:01,570 --> 00:21:03,641
and it's at risk of choking.
273
00:21:09,164 --> 00:21:13,962
It's hard to know how
this has happened.
274
00:21:13,996 --> 00:21:17,103
Even the mother seems
confused and stressed.
275
00:21:34,845 --> 00:21:37,296
The more she moves around,
276
00:21:37,330 --> 00:21:39,850
the more she pulls
on the chick's neck.
277
00:21:57,350 --> 00:22:00,526
It's a lucky escape.
278
00:22:00,560 --> 00:22:03,874
But now it's stuck on its back.
279
00:22:03,908 --> 00:22:06,773
Dad's busy looking
after the other chick,
280
00:22:06,808 --> 00:22:08,672
and doesn't seem
to want to help.
281
00:22:10,294 --> 00:22:12,469
Less than half of
all bald eagle chicks
282
00:22:12,503 --> 00:22:16,231
will survive their first year.
283
00:22:17,646 --> 00:22:19,752
The odds may be against it,
284
00:22:19,786 --> 00:22:25,447
but those powerful
talons come to the rescue.
285
00:22:29,589 --> 00:22:31,108
Over the next few weeks,
286
00:22:31,142 --> 00:22:34,905
the parents will bring
in around five fish a day
287
00:22:34,939 --> 00:22:38,874
to help the chicks grow.
288
00:22:38,909 --> 00:22:40,359
And by a month old,
289
00:22:40,393 --> 00:22:44,535
some obvious
changes start to show.
290
00:22:46,468 --> 00:22:48,332
Their fluffy thermal down,
291
00:22:48,367 --> 00:22:51,128
which has kept them
warm all this time,
292
00:22:51,162 --> 00:22:54,131
is slowly being covered
by juvenile flight feathers.
293
00:22:55,684 --> 00:22:57,065
These will continue to grow
294
00:22:57,099 --> 00:22:59,585
until they reach
their maximum length,
295
00:22:59,619 --> 00:23:01,932
around the time they fledge.
296
00:23:04,244 --> 00:23:09,595
But perhaps the most
important change is in their vision.
297
00:23:09,629 --> 00:23:12,667
Their eyes open
within hours of hatching,
298
00:23:12,701 --> 00:23:14,462
but much like a human baby,
299
00:23:14,496 --> 00:23:18,776
it's thought they're
born with poor sight.
300
00:23:18,811 --> 00:23:22,504
It takes a few weeks for
their eyesight to sharpen
301
00:23:22,539 --> 00:23:24,541
and become one of the
most powerful senses
302
00:23:24,575 --> 00:23:27,854
in the animal world.
303
00:23:30,616 --> 00:23:32,514
Eagles' vision is phenomenal.
304
00:23:32,549 --> 00:23:34,551
They have different
areas in their retina
305
00:23:34,585 --> 00:23:36,760
that allow them to have
increased visual acuity.
306
00:23:36,794 --> 00:23:39,797
It's very important that
they have that visual acuity
307
00:23:39,832 --> 00:23:45,285
to be able to capture their prey
and be successful in the hunt.
308
00:23:46,770 --> 00:23:49,773
We describe anyone
with exceptional sight
309
00:23:49,807 --> 00:23:52,741
as "eagle-eyed."
310
00:23:54,536 --> 00:23:57,953
But just how good is it?
311
00:24:00,404 --> 00:24:01,957
To find out,
312
00:24:01,992 --> 00:24:05,478
Lloyd Buck has brought
his golden eagle, Tilly,
313
00:24:05,513 --> 00:24:08,826
to a remote part of Scotland.
314
00:24:18,008 --> 00:24:21,460
They're joined by
Professor Graham Martin,
315
00:24:21,494 --> 00:24:24,324
an expert in avian vision.
316
00:24:27,120 --> 00:24:29,053
I'm intrigued to learn more
317
00:24:29,088 --> 00:24:31,090
about just how
good her eyesight is.
318
00:24:31,124 --> 00:24:33,161
Okay, well, I think we
can set something up.
319
00:24:33,195 --> 00:24:35,266
A sort of game of hide
and seek, perhaps?
320
00:24:36,923 --> 00:24:41,065
Tilly must find Lloyd
somewhere in this landscape.
321
00:24:41,100 --> 00:24:45,518
Her cage has been
covered, so she can't cheat.
322
00:24:45,553 --> 00:24:49,522
Lloyd has found a position
one-and-a-half miles away
323
00:24:49,557 --> 00:24:51,869
on the other side of the glen,
324
00:24:51,904 --> 00:24:55,528
and weather
conditions are not ideal.
325
00:24:55,563 --> 00:24:58,566
Even with a powerful
telephoto lens,
326
00:24:58,600 --> 00:25:01,327
it's hard to pick out
Graham and Tilly.
327
00:25:01,361 --> 00:25:02,984
It's a long way.
328
00:25:03,018 --> 00:25:06,228
I cannot see you without
a pair of binoculars,
329
00:25:06,263 --> 00:25:07,436
and even with the binoculars,
330
00:25:07,471 --> 00:25:10,094
there's that much
moisture in the air, so...
331
00:25:10,129 --> 00:25:12,890
Let's see what she does
now... this is the big test.
332
00:25:12,925 --> 00:25:16,169
Okay, then, well, I'll, I'll
release her now, okay?
333
00:25:16,204 --> 00:25:18,758
Okay, good luck...
come on, Tilly.
334
00:25:18,793 --> 00:25:19,759
Come on, Tills.
335
00:25:22,279 --> 00:25:24,212
She's off.
336
00:25:24,246 --> 00:25:27,353
She's looking very hard.
337
00:25:27,387 --> 00:25:30,252
I'm sure she's
trying to find you.
338
00:25:30,287 --> 00:25:33,497
Tilly has never faced
a challenge like this,
339
00:25:33,532 --> 00:25:36,500
but she appears to spot
Lloyd almost immediately
340
00:25:36,535 --> 00:25:39,365
and makes her way to
the other side of the glen.
341
00:25:39,399 --> 00:25:42,644
Come on, Tilly, come on!
342
00:25:45,682 --> 00:25:48,512
Tilly takes an indirect route,
343
00:25:48,547 --> 00:25:51,170
riding a series of
strong air currents
344
00:25:51,204 --> 00:25:54,173
to reach Lloyd more efficiently
345
00:25:54,207 --> 00:25:56,727
and much faster.
346
00:25:56,762 --> 00:26:00,628
She's coming in, she's
coming in fast, whoo-hoo!
347
00:26:00,662 --> 00:26:02,043
She's done it, Graham.
348
00:26:02,077 --> 00:26:03,596
Absolutely hammering
across the valley.
349
00:26:05,943 --> 00:26:08,014
What a bird she is.
350
00:26:14,503 --> 00:26:17,817
You clever bird.
351
00:26:17,852 --> 00:26:19,612
Whoo-hoo!
352
00:26:19,647 --> 00:26:21,787
What an eagle you are, eh?
353
00:26:21,821 --> 00:26:23,167
Hello!
354
00:26:24,962 --> 00:26:26,964
Graham, she's on my arm.
355
00:26:26,999 --> 00:26:30,416
That is absolutely incredible...
I'm so pleased with her.
356
00:26:30,450 --> 00:26:33,005
I've never asked her
to find me like that.
357
00:26:33,039 --> 00:26:35,490
That is actually
very, very impressive
358
00:26:35,524 --> 00:26:37,803
because it took really
very little time at all.
359
00:26:39,459 --> 00:26:42,531
Tilly spotted Lloyd in
this enormous landscape
360
00:26:42,566 --> 00:26:45,258
from a mile and a half away,
361
00:26:45,293 --> 00:26:49,711
a feat so impressive, it
seems almost super powered.
362
00:26:51,299 --> 00:26:53,128
So how does she achieve this?
363
00:26:54,889 --> 00:26:58,237
Much like a human's
eye, images are projected
364
00:26:58,271 --> 00:27:03,242
onto the retina at the
back of the eagle's eye.
365
00:27:03,276 --> 00:27:08,178
This area is covered with light
sensitive cells known as cones.
366
00:27:08,212 --> 00:27:12,009
The more cones, the
sharper the eyesight.
367
00:27:12,044 --> 00:27:16,911
A human eye may have 200,000
cones per square millimeter.
368
00:27:16,945 --> 00:27:20,673
But eagles can have
over twice as many,
369
00:27:20,708 --> 00:27:22,848
giving them the
sharpest eyesight
370
00:27:22,882 --> 00:27:25,609
of any vertebrate animal.
371
00:27:27,922 --> 00:27:31,788
The eagles'
supreme visual acuity
372
00:27:31,822 --> 00:27:35,446
gives them a huge advantage.
373
00:27:35,481 --> 00:27:39,554
It means they can quickly pick
out prey in a vast landscape.
374
00:27:40,969 --> 00:27:43,178
But there's an
unexpected downside
375
00:27:43,213 --> 00:27:46,078
to having such sharp vision.
376
00:27:46,112 --> 00:27:50,392
The problem is you don't
want to get the sun in your eyes.
377
00:27:50,427 --> 00:27:53,533
It would destroy all the
very high acuity it's got.
378
00:27:53,568 --> 00:27:54,776
So they have these big eyebrows,
379
00:27:54,811 --> 00:27:55,984
it's like wearing
a baseball cap.
380
00:27:56,019 --> 00:27:57,365
Yeah. That's all designed
381
00:27:57,399 --> 00:27:58,711
to keep the sun
out of their eyes
382
00:27:58,746 --> 00:28:00,955
so they don't actually
ever image the sun.
383
00:28:00,989 --> 00:28:04,786
This brow ridge is
what gives eagles
384
00:28:04,821 --> 00:28:06,581
their fearsome stare.
385
00:28:08,065 --> 00:28:11,275
But it has a serious drawback.
386
00:28:11,310 --> 00:28:13,036
Of course, if you've
got... keeping the sun
387
00:28:13,070 --> 00:28:15,901
out of your eyes, you can't
actually see what's up there.
388
00:28:15,935 --> 00:28:18,248
What an eagle
wants to do is patrol
389
00:28:18,282 --> 00:28:20,733
and look down at
the big terrain below it,
390
00:28:20,768 --> 00:28:22,390
and it's bending
its head forward,
391
00:28:22,424 --> 00:28:24,772
it's tipping its head
down to have a look.
392
00:28:24,806 --> 00:28:26,601
And that means
that this blind area
393
00:28:26,635 --> 00:28:28,637
which is designed to keep
the sun out of their eyes
394
00:28:28,672 --> 00:28:30,363
is stopping them actually
looking where they're going.
395
00:28:32,365 --> 00:28:36,300
This blind spot is not
normally a problem.
396
00:28:36,335 --> 00:28:42,444
In their natural environment,
they soar high above the trees.
397
00:28:42,479 --> 00:28:47,864
But in a modern landscape,
it can be a fatal flaw.
398
00:28:47,898 --> 00:28:49,106
Across the world,
399
00:28:49,141 --> 00:28:53,766
eagles are colliding with
man-made structures.
400
00:28:53,801 --> 00:28:56,286
Wind turbines,
which are often built
401
00:28:56,320 --> 00:29:00,497
in wild landscapes,
are a particular problem.
402
00:29:00,531 --> 00:29:03,258
So, at this wind
farm in Wyoming,
403
00:29:03,293 --> 00:29:06,296
environmental
scientists like Misti Sporer
404
00:29:06,330 --> 00:29:09,644
are trying to
protect the eagles.
405
00:29:09,678 --> 00:29:11,853
This is the eagle
observation tower.
406
00:29:11,888 --> 00:29:15,339
So when they see an
eagle enter into the area
407
00:29:15,374 --> 00:29:17,341
where the turbine blade
would pass through,
408
00:29:17,376 --> 00:29:18,998
they will shut that turbine down
409
00:29:19,033 --> 00:29:23,106
and the eagle is able to pass
through the area going unharmed.
410
00:29:23,140 --> 00:29:25,280
And then once
that eagle has left,
411
00:29:25,315 --> 00:29:26,557
they start the turbine back up,
412
00:29:26,592 --> 00:29:29,181
so we can continue
generating electricity.
413
00:29:29,215 --> 00:29:32,667
So, we do lose a little bit of
energy throughout the process
414
00:29:32,701 --> 00:29:34,151
but it's worth it
to save an eagle.
415
00:29:36,050 --> 00:29:39,605
But human eyesight
isn't always reliable.
416
00:29:39,639 --> 00:29:42,297
When an eagle flies
against the sunlight,
417
00:29:42,332 --> 00:29:43,712
it can be hard to spot.
418
00:29:45,059 --> 00:29:48,131
So this wind farm is now
using artificial intelligence
419
00:29:48,165 --> 00:29:52,791
to improve their odds.
420
00:29:52,825 --> 00:29:55,034
Identi-Flight utilizes eight
cameras around the bottom,
421
00:29:55,069 --> 00:29:58,693
so it can see in 360 degrees.
422
00:29:58,727 --> 00:29:59,901
There are two cameras up top
423
00:29:59,936 --> 00:30:01,938
that are capable
of tracking an object
424
00:30:01,972 --> 00:30:03,836
as it flies through an area.
425
00:30:03,871 --> 00:30:08,392
In just one second, the
system can figure out
426
00:30:08,427 --> 00:30:11,499
if a flying object
is an eagle or not,
427
00:30:11,533 --> 00:30:13,397
and only if it flies too close
428
00:30:13,432 --> 00:30:18,678
will it temporarily shut
down any turbines in its path.
429
00:30:18,713 --> 00:30:20,715
It's over five times
more effective
430
00:30:20,749 --> 00:30:22,130
at seeing birds than humans,
431
00:30:22,165 --> 00:30:27,101
meaning the eagles
here are now much safer.
432
00:30:34,108 --> 00:30:37,525
But across the world,
the biggest threats
433
00:30:37,559 --> 00:30:40,977
to eagles are still humans.
434
00:30:44,981 --> 00:30:47,638
In areas around the tropics,
435
00:30:47,673 --> 00:30:50,365
deforestation is
threatening jungle species
436
00:30:50,400 --> 00:30:52,298
like the Philippine eagle...
437
00:30:55,232 --> 00:30:57,579
And the harpy eagle.
438
00:30:59,443 --> 00:31:01,894
There are fewer trees
for them to nest in...
439
00:31:04,448 --> 00:31:07,417
And far less prey
for them to hunt.
440
00:31:09,937 --> 00:31:14,251
Many eagles are also
dying from lead poisoning,
441
00:31:14,286 --> 00:31:19,636
as hunting ammunition
contaminates leftover carcasses.
442
00:31:19,670 --> 00:31:23,674
In total, more than a
third of all eagle species
443
00:31:23,709 --> 00:31:26,988
are considered to be
endangered or vulnerable.
444
00:31:28,472 --> 00:31:31,717
In the past, conservationists
have been forced
445
00:31:31,751 --> 00:31:34,168
to take drastic
action to save eagles
446
00:31:34,202 --> 00:31:37,999
on the brink of extinction.
447
00:31:41,520 --> 00:31:46,732
During the 1940s,
DDT, a potent insecticide,
448
00:31:46,766 --> 00:31:49,148
was sprayed widely
across the U.S.
449
00:31:49,183 --> 00:31:53,601
to treat pest problems,
large or small.
450
00:31:53,635 --> 00:31:58,399
It was even sprayed on
humans to rid them of parasites.
451
00:32:01,264 --> 00:32:04,853
But DDT seeped
into the ecosystems
452
00:32:04,888 --> 00:32:08,616
and passed from
prey to predator,
453
00:32:08,650 --> 00:32:10,273
so those at the top,
454
00:32:10,307 --> 00:32:13,862
especially eagles,
were hit hard.
455
00:32:15,312 --> 00:32:18,108
It caused a thinning
in eagle eggs,
456
00:32:18,143 --> 00:32:21,353
so they often cracked
during incubation,
457
00:32:21,387 --> 00:32:26,151
and it almost wiped them
out from parts of the U.S.A.
458
00:32:29,223 --> 00:32:33,434
In 1972, DDT was
banned in the U.S.,
459
00:32:33,468 --> 00:32:38,715
and some extreme conservation
measures were launched.
460
00:32:38,749 --> 00:32:40,510
Eggs were taken from the wild,
461
00:32:40,544 --> 00:32:44,134
hatched safely in captivity,
462
00:32:46,723 --> 00:32:49,139
and the chicks were
returned to the nest
463
00:32:49,174 --> 00:32:51,072
to be reared naturally.
464
00:32:52,556 --> 00:32:54,973
And it worked.
465
00:32:58,977 --> 00:33:05,190
There are now thought to be
over 140,000 bald eagles in the U.S.
466
00:33:05,224 --> 00:33:08,779
It's a truly
remarkable comeback.
467
00:33:17,478 --> 00:33:18,582
In Iowa,
468
00:33:18,617 --> 00:33:22,276
the eaglets have their
own dangers to deal with.
469
00:33:24,933 --> 00:33:27,212
They're now eight weeks old,
470
00:33:27,246 --> 00:33:31,457
and have undergone
some remarkable changes.
471
00:33:31,492 --> 00:33:34,840
They're nearly fully grown,
472
00:33:34,874 --> 00:33:38,809
and their feathers are
almost entirely black.
473
00:33:38,844 --> 00:33:43,400
But something seems
to be bothering them.
474
00:33:43,435 --> 00:33:46,265
A wet spring has
created ideal conditions
475
00:33:46,300 --> 00:33:50,062
for an infestation of
blood-sucking black flies,
476
00:33:50,097 --> 00:33:53,790
and they're
attacking the eaglets.
477
00:33:53,824 --> 00:33:55,585
Black flies, which are
also called buffalo gnats,
478
00:33:55,619 --> 00:33:57,690
pose a problem for young chicks,
479
00:33:57,725 --> 00:33:59,899
not necessarily
because of a single bite
480
00:33:59,934 --> 00:34:02,626
but because they often attack
the chicks in large swarms
481
00:34:02,661 --> 00:34:04,249
and you get
multiple bite wounds.
482
00:34:04,283 --> 00:34:06,423
And typically
chicks will succumb
483
00:34:06,458 --> 00:34:09,668
to either blood loss or
even anaphylactic shock
484
00:34:09,702 --> 00:34:10,772
related to the bite.
485
00:34:13,189 --> 00:34:16,295
As weather patterns
change year after year,
486
00:34:16,330 --> 00:34:18,608
the number of black
flies seems to be
487
00:34:18,642 --> 00:34:20,782
getting higher in this region,
488
00:34:20,817 --> 00:34:23,820
and this season
is especially bad.
489
00:34:25,856 --> 00:34:28,204
It's almost certainly
making the chicks weaker,
490
00:34:28,238 --> 00:34:32,691
but worse still,
the constant biting
491
00:34:32,725 --> 00:34:34,382
is making them restless.
492
00:34:42,839 --> 00:34:45,462
One youngster becomes
so uncomfortable,
493
00:34:45,497 --> 00:34:50,226
it climbs the tree to get away.
494
00:34:50,260 --> 00:34:55,714
70 feet up, this
is a risky move.
495
00:34:58,544 --> 00:35:01,202
It's too young to fledge,
496
00:35:01,237 --> 00:35:05,448
and too weak to deal
with the strong wind.
497
00:35:05,482 --> 00:35:09,590
In desperation, it leaps...
498
00:35:09,624 --> 00:35:13,387
and falls to the ground.
499
00:35:13,421 --> 00:35:17,149
The team monitoring
the nest raise the alarm
500
00:35:17,184 --> 00:35:18,978
and send out a search party.
501
00:35:24,191 --> 00:35:26,503
But, in the meantime,
the youngest chick
502
00:35:26,538 --> 00:35:30,024
is also driven from
the nest by the flies.
503
00:35:43,658 --> 00:35:49,077
It still doesn't have full
control of those big talons,
504
00:35:49,112 --> 00:35:52,943
and one mistake is all it takes.
505
00:36:02,263 --> 00:36:05,473
It's a catastrophe.
506
00:36:07,441 --> 00:36:11,479
Somehow, the search
team find it alive,
507
00:36:11,514 --> 00:36:15,276
covered in black fly bites.
508
00:36:15,311 --> 00:36:16,519
But, unfortunately,
509
00:36:16,553 --> 00:36:19,763
the eldest chick is still
nowhere to be seen.
510
00:36:23,215 --> 00:36:25,286
If the chicks were older,
511
00:36:25,321 --> 00:36:28,807
they could have flown to safety.
512
00:36:28,841 --> 00:36:30,360
But they didn't
have time to develop
513
00:36:30,395 --> 00:36:34,192
the strength and
coordination required
514
00:36:34,226 --> 00:36:37,367
for one of the eagle's
most essential skills...
515
00:36:37,402 --> 00:36:40,474
flight.
516
00:36:40,508 --> 00:36:41,751
If you have the opportunity,
517
00:36:41,785 --> 00:36:44,443
just watch an eagle fly,
you can certainly appreciate
518
00:36:44,478 --> 00:36:47,860
their majesty, their
grandeur, their ability.
519
00:36:47,895 --> 00:36:50,863
Watching an eagle
soar is freeing,
520
00:36:50,898 --> 00:36:54,764
it's gratifying,
it lifts you up.
521
00:36:57,076 --> 00:36:59,734
Eagles dominate the sky.
522
00:37:02,220 --> 00:37:06,465
They can dive at around
150 miles per hour.
523
00:37:06,500 --> 00:37:10,849
And perform surprising
aerobatics when they fight
524
00:37:10,883 --> 00:37:13,748
or display to a mate.
525
00:37:13,783 --> 00:37:17,649
And one of their
greatest aerial abilities
526
00:37:17,683 --> 00:37:19,409
is soaring.
527
00:37:22,550 --> 00:37:24,518
Golden eagles can
have a home range
528
00:37:24,552 --> 00:37:28,591
of over 1,000 square miles.
529
00:37:28,625 --> 00:37:30,248
To cover such vast distances,
530
00:37:30,282 --> 00:37:35,701
they use air currents to
push them high into the air
531
00:37:35,736 --> 00:37:40,258
without flapping their wings,
saving them precious energy.
532
00:37:47,126 --> 00:37:49,025
It's something Lloyd
Buck has always
533
00:37:49,059 --> 00:37:51,614
wanted to know more about.
534
00:37:53,926 --> 00:37:57,827
So he's come to California,
where paragliding expert
535
00:37:57,861 --> 00:38:03,764
Michael Vergalla often flies
alongside wild birds of prey.
536
00:38:03,798 --> 00:38:06,905
By learning what it
takes to fly a paraglider,
537
00:38:06,939 --> 00:38:10,426
Lloyd hopes he will understand
more about how eagles soar.
538
00:38:10,460 --> 00:38:14,257
Bring the wing up
in three, two, one.
539
00:38:14,292 --> 00:38:15,948
Wing's coming up.
540
00:38:18,675 --> 00:38:21,368
Okay, walk, walk, walk, walk.
541
00:38:21,402 --> 00:38:24,716
Start running... run, run,
run, run, run, run, run, run, run!
542
00:38:29,721 --> 00:38:30,687
All right, Lloyd.
543
00:38:30,722 --> 00:38:34,035
Okay, here we go.
544
00:38:34,070 --> 00:38:36,106
We're flying. We're flying Mike.
545
00:38:38,350 --> 00:38:41,491
Wow!
546
00:38:46,945 --> 00:38:49,844
I've seen Tilly do
this so many times
547
00:38:49,879 --> 00:38:53,331
and now I'm doing it.
548
00:38:53,365 --> 00:38:55,056
Just like an eagle,
549
00:38:55,091 --> 00:38:56,748
Mike is trying to gain altitude
550
00:38:56,782 --> 00:38:59,992
by harnessing two
common air currents.
551
00:39:02,788 --> 00:39:06,620
Thermals form as the
sun heats the earth,
552
00:39:06,654 --> 00:39:10,727
which in turn warms
the air above it,
553
00:39:10,762 --> 00:39:13,005
creating a rising column of air.
554
00:39:16,250 --> 00:39:19,253
Updrafts are created
when horizontal winds
555
00:39:19,287 --> 00:39:22,187
are deflected
skywards by a ridge.
556
00:39:24,638 --> 00:39:26,847
Mike searches for tiny clues
557
00:39:26,881 --> 00:39:30,747
to help find these air
currents and climb higher.
558
00:39:30,782 --> 00:39:33,440
You're looking for
changes, you're smelling,
559
00:39:33,474 --> 00:39:36,857
you're listening, you're
trying to use all of your senses
560
00:39:36,891 --> 00:39:39,100
to figure out what's happening.
561
00:39:39,135 --> 00:39:40,999
This is what Tilly feels,
this is what Tilly does,
562
00:39:41,033 --> 00:39:42,345
this is what eagles do. Uh-huh.
563
00:39:44,243 --> 00:39:46,142
One of Mike's favorite ways
564
00:39:46,176 --> 00:39:47,592
to find a good thermal
565
00:39:47,626 --> 00:39:51,527
is to watch and
follow the local birds.
566
00:39:51,561 --> 00:39:53,977
We've got another
bird on this ridge here
567
00:39:54,012 --> 00:39:55,565
that we can try to join.
568
00:39:57,498 --> 00:40:00,052
Mike can tell how
strong a thermal is
569
00:40:00,087 --> 00:40:04,229
by seeing how
quickly the birds climb.
570
00:40:04,263 --> 00:40:07,957
And it's not long before
they spot a special species.
571
00:40:07,991 --> 00:40:10,304
Look out at the
end of the ridge.
572
00:40:10,338 --> 00:40:11,754
Do you see the birds?
573
00:40:13,721 --> 00:40:15,240
That's a goldie.
574
00:40:15,274 --> 00:40:16,931
That's a golden eagle. Yep.
575
00:40:16,966 --> 00:40:18,381
Let's get it, let's go.
576
00:40:18,416 --> 00:40:20,176
We're flying with
a golden eagle.
577
00:40:20,210 --> 00:40:21,177
Wow!
578
00:40:26,458 --> 00:40:28,322
I've waited my whole
life for this, Mike.
579
00:40:48,135 --> 00:40:51,966
This is the thing that I've
dreamt about since I was a boy.
580
00:40:55,038 --> 00:40:57,972
And my whole life I've
experienced it through my birds.
581
00:40:58,007 --> 00:40:59,698
Uh-huh.
582
00:40:59,733 --> 00:41:01,976
But now I've experienced
it for myself for real with you
583
00:41:02,011 --> 00:41:04,427
and this is just...
584
00:41:04,462 --> 00:41:05,566
I can't put that into words,
585
00:41:05,601 --> 00:41:07,534
it's really quite
moving I would say,
586
00:41:07,568 --> 00:41:09,121
it's quite emotional.
587
00:41:10,675 --> 00:41:12,608
It's okay, you
can cry. I've cried.
588
00:41:12,642 --> 00:41:14,195
I feel quite...
589
00:41:14,230 --> 00:41:17,509
I feel very emotional actually.
590
00:41:20,339 --> 00:41:22,928
This is something, Mike,
I'm never going to forget
591
00:41:22,963 --> 00:41:24,620
for the rest of my life.
592
00:41:27,277 --> 00:41:32,662
For Lloyd, soaring on
the air currents is pure joy.
593
00:41:32,697 --> 00:41:37,909
But for eagles, it's a critical
component of their daily lives.
594
00:41:40,394 --> 00:41:42,914
To be a dominant
predator of the sky,
595
00:41:42,948 --> 00:41:47,401
they must harness the
wind to cover their territory,
596
00:41:47,435 --> 00:41:49,783
and they make it look easy.
597
00:41:57,584 --> 00:42:02,071
To find out just how
good eagles are at soaring,
598
00:42:02,105 --> 00:42:07,490
Lloyd wants to
put Tilly to the test.
599
00:42:07,525 --> 00:42:10,562
He's fitting her with a
highly accurate GPS tracker,
600
00:42:10,597 --> 00:42:14,462
to measure how fast
she can gain altitude.
601
00:42:14,497 --> 00:42:18,121
And a 360-degree camera
to see how her wings
602
00:42:18,156 --> 00:42:22,850
are adapted to soaring.
603
00:42:22,885 --> 00:42:27,303
We'll know exactly
what you get up to, eh?
604
00:42:27,337 --> 00:42:29,305
You're a good girl, yes.
605
00:42:31,756 --> 00:42:34,759
Go on, off you go. Go on.
606
00:42:39,073 --> 00:42:42,594
Tilly quickly finds an updraft
607
00:42:42,629 --> 00:42:45,321
and soars high above the glen.
608
00:42:46,978 --> 00:42:49,912
You make it look so easy, eh?
609
00:42:51,603 --> 00:42:54,502
The 360 camera provides
a wonderful opportunity
610
00:42:54,537 --> 00:42:59,093
to see the world from
an eagle's perspective.
611
00:43:28,778 --> 00:43:29,745
Throughout the flight,
612
00:43:29,779 --> 00:43:32,471
the GPS tracker
and accelerometer
613
00:43:32,506 --> 00:43:36,268
on her back have been
collecting vital information.
614
00:43:44,104 --> 00:43:45,864
Good girl, clever eagle!
615
00:43:53,147 --> 00:43:55,149
Professor Jim Usherwood,
616
00:43:55,184 --> 00:43:59,913
a locomotion specialist,
can help interpret the findings.
617
00:43:59,947 --> 00:44:01,500
Well, it's really exciting,
618
00:44:01,535 --> 00:44:02,950
especially to having
the video next to her,
619
00:44:02,985 --> 00:44:04,331
you can really see what's
happening all the way through.
620
00:44:04,365 --> 00:44:09,129
We can see her climbing,
circling seven times,
621
00:44:09,163 --> 00:44:12,201
and then reaching quite a
height really very quickly.
622
00:44:12,235 --> 00:44:15,238
She's doing... ooh, three,
four, five meters a second up.
623
00:44:15,273 --> 00:44:16,861
Wow.
624
00:44:16,895 --> 00:44:18,379
- And that's fast.
- Yeah.
625
00:44:18,414 --> 00:44:21,037
That's sort of eight,
nine, ten miles an hour up.
626
00:44:21,072 --> 00:44:22,176
Imagine running
up a ladder that fast.
627
00:44:22,211 --> 00:44:23,833
So she's climbing quickly?
628
00:44:23,868 --> 00:44:25,110
Really fast,
629
00:44:25,145 --> 00:44:27,423
while hardly traveling
across the ground at all.
630
00:44:28,666 --> 00:44:30,253
Tilly climbs at this rate
631
00:44:30,288 --> 00:44:35,811
without flapping her wings,
saving huge amounts of energy.
632
00:44:37,191 --> 00:44:40,263
Eagles are able to ride
the aircurrents effectively
633
00:44:40,298 --> 00:44:43,750
thanks to their large wing area,
634
00:44:43,784 --> 00:44:46,476
but the shape of their
wing is different compared
635
00:44:46,511 --> 00:44:50,170
to many soaring specialists.
636
00:44:53,967 --> 00:44:59,075
Albatross have narrow
wings up to 11 feet long,
637
00:44:59,110 --> 00:45:00,594
which generate a lot of lift
638
00:45:00,628 --> 00:45:03,217
for relatively small
amounts of drag.
639
00:45:06,117 --> 00:45:09,741
This wing shape
is perfect for gliding,
640
00:45:09,776 --> 00:45:11,709
but it's no good to eagles.
641
00:45:14,573 --> 00:45:16,921
Long wings are very good
for gliding and soaring,
642
00:45:16,955 --> 00:45:19,647
but they're
horrible for flapping
643
00:45:19,682 --> 00:45:21,097
and of course this
thing, at some point,
644
00:45:21,132 --> 00:45:23,341
will need to flap. Yeah.
645
00:45:23,375 --> 00:45:24,860
She'll need to flap to take off,
646
00:45:24,894 --> 00:45:26,344
carry the weaponry
to kill something,
647
00:45:26,378 --> 00:45:27,794
and then carry that
food back home,
648
00:45:27,828 --> 00:45:30,797
at which point you don't
actually want super-long wings.
649
00:45:32,591 --> 00:45:35,940
Eagles have to deal with
some competing priorities.
650
00:45:37,493 --> 00:45:41,014
To soar well, they
need to be lightweight,
651
00:45:41,048 --> 00:45:44,431
with extremely long wings.
652
00:45:45,915 --> 00:45:47,986
But to hunt large prey,
653
00:45:48,021 --> 00:45:50,644
they need to be
powerful and heavy,
654
00:45:50,678 --> 00:45:52,577
with shorter, broad wings
655
00:45:52,611 --> 00:45:55,442
that aid maneuverability
and takeoff.
656
00:45:57,685 --> 00:46:00,240
Eagles achieve both...
657
00:46:00,274 --> 00:46:04,658
they manage to create lots
of lift with limited wing length.
658
00:46:04,692 --> 00:46:07,903
So how do they do it?
659
00:46:07,937 --> 00:46:13,253
A key secret is at
the end of their wings.
660
00:46:13,287 --> 00:46:16,497
From Tilly's 360 camera,
it's possible to see
661
00:46:16,532 --> 00:46:19,811
that the feathers on her
wingtips are separated.
662
00:46:23,159 --> 00:46:25,748
Each one of these
primary feathers
663
00:46:25,783 --> 00:46:28,440
acts like a tiny airfoil,
664
00:46:28,475 --> 00:46:32,479
helping air hug the
upper surface of the wing.
665
00:46:32,513 --> 00:46:34,550
It means eagles
can tilt their wings
666
00:46:34,584 --> 00:46:37,415
at very steep angles on takeoff,
667
00:46:37,449 --> 00:46:42,144
generating lots of lift
to support a heavy load.
668
00:46:45,354 --> 00:46:47,563
It's also thought
these slotted wingtips
669
00:46:47,597 --> 00:46:50,393
can reduce elements of drag,
670
00:46:50,428 --> 00:46:54,156
helping them soar
with greater efficiency.
671
00:46:57,228 --> 00:46:59,126
It's a powerful
solution for a wing
672
00:46:59,161 --> 00:47:02,405
that has to perform
so many tasks.
673
00:47:07,065 --> 00:47:09,516
The eagles' dominance of the sky
674
00:47:09,550 --> 00:47:13,589
is partly what has made
them such iconic creatures.
675
00:47:15,349 --> 00:47:17,765
And why they
feature so prominently
676
00:47:17,800 --> 00:47:20,941
in cultures around the
world, including many
677
00:47:20,976 --> 00:47:24,013
Native American tribes.
678
00:47:24,048 --> 00:47:26,119
Only the eagle
679
00:47:26,153 --> 00:47:28,431
can fly high enough
and far enough
680
00:47:28,466 --> 00:47:32,539
to actually see the face of God.
681
00:47:32,573 --> 00:47:35,473
We are truly a
people of the eagle,
682
00:47:35,507 --> 00:47:37,509
and it comes out in our dress
683
00:47:37,544 --> 00:47:41,203
and everything about
our ceremonial presence.
684
00:47:45,379 --> 00:47:47,554
William Voelker
685
00:47:47,588 --> 00:47:50,695
is a member of the
Comanche tribe in Oklahoma
686
00:47:50,729 --> 00:47:53,905
and has set up a
special eagle sanctuary
687
00:47:53,940 --> 00:47:57,046
to help support
their traditions.
688
00:47:57,081 --> 00:47:58,289
So to take an eagle feather
689
00:47:58,323 --> 00:48:02,189
and to call on the energy
of this messenger bird,
690
00:48:02,224 --> 00:48:05,192
it's our direct link
with the almighty.
691
00:48:05,227 --> 00:48:08,057
So the eagle is essential
in our spiritual way of life.
692
00:48:09,714 --> 00:48:11,819
Historically, eagles
and their feathers
693
00:48:11,854 --> 00:48:15,685
have been taken from the
wild to supply these traditions,
694
00:48:15,720 --> 00:48:19,620
often resulting in
the death of the birds.
695
00:48:19,655 --> 00:48:22,969
But times are changing.
696
00:48:23,003 --> 00:48:24,902
An eagle can no longer
697
00:48:24,936 --> 00:48:29,147
forfeit its life to benefit
culture, anybody's culture.
698
00:48:29,182 --> 00:48:31,770
Those days are gone.
699
00:48:31,805 --> 00:48:34,601
In today's world we have
a cultural responsibility
700
00:48:34,635 --> 00:48:39,019
to doing everything we can
to enhance eagle populations.
701
00:48:41,573 --> 00:48:43,196
At his sanctuary,
702
00:48:43,230 --> 00:48:46,026
William has successfully
raised and released
703
00:48:46,061 --> 00:48:49,409
over 400 eagles and
hawks into the wild.
704
00:48:49,443 --> 00:48:53,413
He also cares for
many more in captivity.
705
00:48:53,447 --> 00:48:56,623
And as these birds
naturally molt their feathers,
706
00:48:56,657 --> 00:48:59,833
William passes them on
to Native American tribes
707
00:48:59,867 --> 00:49:03,699
so the wild populations
can be left unharmed.
708
00:49:12,742 --> 00:49:16,539
Back in Iowa, the
nest remains empty.
709
00:49:16,574 --> 00:49:18,196
But remarkably,
710
00:49:18,231 --> 00:49:22,821
the eldest eaglet has
also been found alive.
711
00:49:31,347 --> 00:49:36,111
It was discovered washed
up downriver with a broken leg,
712
00:49:36,145 --> 00:49:39,183
five days after it
fell from the nest.
713
00:49:49,503 --> 00:49:50,780
Both eaglets were taken
714
00:49:50,815 --> 00:49:54,646
to a raptor rehabilitation
center for treatment.
715
00:49:54,681 --> 00:49:58,857
It's a reminder that although
eagles are an apex predator,
716
00:49:58,892 --> 00:50:02,827
they sometimes need our help.
717
00:50:04,311 --> 00:50:06,969
Over the next several months,
718
00:50:07,004 --> 00:50:10,179
the eldest eagle's
leg gradually heals.
719
00:50:12,699 --> 00:50:17,048
With care and support
from the raptor center's staff,
720
00:50:17,083 --> 00:50:20,258
both eagles grow stronger.
721
00:50:24,297 --> 00:50:29,060
They're given space to develop
their powerful flight muscles.
722
00:50:35,480 --> 00:50:39,001
Finally, the youngest eagle
is ready to be released.
723
00:50:42,901 --> 00:50:47,458
At last it has its own
freedom and independence.
724
00:50:50,392 --> 00:50:54,327
Almost six months later,
its sibling's leg is healed...
725
00:50:55,742 --> 00:50:58,641
and it, too,
returns to the wild.
726
00:51:03,439 --> 00:51:06,304
By following the journey
from egg to eaglet,
727
00:51:06,339 --> 00:51:09,963
we've seen what challenges
an eagle must overcome
728
00:51:09,997 --> 00:51:12,586
to survive its first year.
729
00:51:15,279 --> 00:51:17,867
And a very special
eagle, called Tilly,
730
00:51:17,902 --> 00:51:22,976
has helped reveal the secrets
behind their greatest abilities,
731
00:51:23,010 --> 00:51:25,634
like their unrivaled vision...
732
00:51:25,668 --> 00:51:29,086
And she's coming
in fast, whoo-hoo!
733
00:51:30,225 --> 00:51:33,780
Their hunting techniques...
734
00:51:33,814 --> 00:51:35,920
and their remarkable soaring...
735
00:51:39,648 --> 00:51:42,789
strength...
736
00:51:42,823 --> 00:51:45,619
agility...
737
00:51:45,654 --> 00:51:49,002
and skill.
738
00:51:49,036 --> 00:51:53,731
Revered around the world,
these stunning raptors can't help
739
00:51:53,765 --> 00:51:57,804
but inspire with their
magnificent eagle power.
56499
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