[Narrator] Feathery looks are back in fashion.

One thing that makes feathers stand out

as a fashion device is that they changed

the profile of the individual.

Charles Darwin even commented in one of his writings

when he said, the head is the chief seat of adornment.

True in people and also true in birds

where you see feathers in a crest

that is visible from a long way off,

telling one bird what species of bird it's looking at.

[Narrator] Biologist and author Thor Hanson

explores the unexpected origins of feathers in fashion

and how our quest for plumes brought

some species to the brink of extinction.

[upbeat music]

We find plumage attractive

in the same way that birds find it attractive.

We have co-opted them for many of the same purposes

for which they evolved in nature.

[Narrator] The history of feathers

in human fashions runs deep.

Indigenous cultures around the world

co-opted feathers from local birds,

often as displays of social status.

The elaborate feather capes

were made in the Hawaiian islands.

On certain south Pacific Islands,

people used them as a currency.

The Aztecs made feathered costumes,

detailed paintings.

The Nazcas in Peru, the Egyptians

had strong traditions about the importance

of feathers in their culture.

So feathers run deep in cultures.

In male fashion, feather work for a long time

was associated with the military

and prowess on the battlefield.

The very phrase, a feather in his cap

comes to us from a tradition

where feathers were added to the helms

of warriors who performed well during battles.

[Narrator] Throughout time, rare and expensive plumes

were used by the wealthy to convey status,

but it wasn't really until the 19th century

that feather work in fashion expanded

and became focused on women's looks,

specifically feathered hats.

Ostrich feathers in particular

had great value as well at that time.

So much so that in South Africa,

there were ostrich ranches

where they had up to a million birds under domestication.

And you could harvest the feathers

from domesticated ostrich sustainably

by clipping the feather off at the base.

And the birds would simply grow

a new set of plumes in the next season.

So ostrich feathers had so much value at that time

that it is a point of fact

that when the Titanic sank in 1912,

the most valuable cargo on the ship

was not some fancy diamond as you might see in the movies,

but it was feathers, 40 cases of prime ostrich plumes,

on their way from the feather merchants

of London to the hat makers of New York City,

and valued in today's dollars at nearly $2.5 million.

[Narrator] At the peak of the Gilded Age bird hat craze,

famed ornithologist Frank Chapman

was astounded at the variety of species

he observed on the streets in 1886.

He walked through the Financial District,

and he quickly managed to tabulate

40 different species of birds

that he might have seen in Central Park,

but they were all adorning the hats

of the women walking down the street.

This of course, was having a terrible impact

on wild bird populations, really, around the world.

[Narrator] One of the casualties

was the Carolina parakeet,

which went extinct in the wild in 1904,

a victim of hunting and deforestation.

Another species being ravaged was the snowy egret.

It had wonderful plumes that held their shape

in all sorts of great ways.

And so it led to do these great hunting efforts

that were wiping out egret colonies.

It doesn't take long for that sort

of hunting practice to bring

the populations crashing down.

The desire for beautiful hats

and other fashion items was driving,

in some cases, close to the extinction

of some of what had once been common birds.

This is where we see the beginnings

of the Audubon Society.

Through groups of women organizing

to push back against this fashion craze.

And it led to this idea that people

should give up something that may have value

economically to preserve things in nature.

It was a radical idea at the time,

but it led to the passing in North America

of bills and laws that are still on the books

protecting birds today.

[Narrator] Eventually, during World War I,

feathered hats began to fall out of favor

with more women entering the workplace

and the rise of automobiless.

Places where fancy plumed hats were inconvenient.

[soft music]

It turns out there are very few things in nature

that have evolved for as many purposes as feathers.

Yes, they can be beautiful and used

for allurement in the birds,

but they have also evolved to be waterproof

to protect the birds from the elements.

There are feathers that are the best insulation we know of,

wonderfully fluffy trapping all that heat

against the body of the bird.

And then of course there are flight feathers

that are an airfoil shape,

giving them wonder maneuverability in flight,

and are now very visible in the fossil evidence

within a particular lineage of dinosaurs,

the theropods which includes

such famous meat heaters as Tyrannosaurus rex

and the Velociraptors they had plumes

that resemble what we see today in birds.

Display was an early use of feathers

way back in the dinosaurs.

There are fossils so well preserved

that they contain structures that allow paleontologists

to interpret the color of the feathers.

These little organelles called melanosomes

are associated with color.

We know that dinosaur feathers were colored.

We know that they must have been used for display.

So this history of plumage

that is used for attracting mates,

used for various displays in the bird kingdom

has a very, very long history.

[upbeat music]

Because feathers are used

in mating rituals to attract a mate,

there's great evolutionary pressure

on their shape and on their color

and on their effectiveness at that task.

And that means that there is a huge range

of feather colors and shapes in nature,

different ways that birds have evolved their plumage

for that sense of allurement.

The birds of paradise have evolved

not only elaborate plumage,

but incredible dances to go along with them

where they have medallions of colored feathers

and they have elaborate wing feathers

where they thrust them up behind them.

So you almost lose the shape of the bird

in this creative display of feather work.

And it's typically the males of the species

that do this sort of display.

And so you end up in these situations

of what biologists call runaway selection,

where because the females have a preference

for a particular look in the males,

there is increased pressure for evolution

to make that look even more and more extreme.

And that leads us to display feathers of a peacock,

for example, totally outrageous,

and with no function in nature

other than to look good for females.

We all know ostriches are flightless.

They gave up the ability to fly

and followed a different evolutionary strategy,

gaining large size, fast, running capabilities

to live on the Savannahs of Africa.

So where you see a typical flight feather

that has a closed vein and an offset rachis

to give it an aerodynamic airfoil shape,

the ostrich is have done away with that completely.

The flight feather of an ostrich looks like this.

The veins are not closed whatsoever.

They have lost all those things

and evolved specifically for purposes of display.

Some biologists feel that the elaborate feather work

is what we call an honest display

that it must be connected

to some advantage that you might get

from mating with that particular male.

Other biologists feel that

this sort of runaway selection

can just be a beauty for beauty's sake.

It doesn't actually connect to anything about their vigor.

It's not unusual to see ostrich's featured

heavily in fashion because they have these wonderful

large, lustrous feathers that aren't used

for display on the birds.

They are decorating her arms in a sense

which is extremely appropriate

because these are flight feathers

from probably a male ostrich

to have that much luster and display.

When we go to a function like the Met Gala,

it's almost like going bird watching in a way,

the idea of allurement to look beautiful,

to attract attention.

Isn't it a happy coincidence we find feathers beautiful

in the same ways that birds do?

They use them to display to one another.

We can borrow them and use them

to display amongst ourselves,

meaning that we have a lot more in common

with our feathered friends

than we might have ever thought.