Bird migration, a perilous journey - Alyssa Klavans

View full lesson: http://ed.ted.com/lessons/bird-migration-a-perilous-journey-alyssa-klavans

Nearly 200 species of songbirds migrate south for winter, some traveling up to 7,000 miles. No easy task, the annual journey is dangerous to birds due to landscape change -- so much so, that only half the birds that migrate south will return home for spring. Alyssa Klavans details why bird migration is so taxing and how we can assist our chirping friends.

Lesson by Alyssa Klavans, animation by Igor Coric.

Each spring, nature lovers eagerly greet the signs

that winter is finally coming to an end.

As the days grow warmer,

the flowers and trees start to bloom,

and the world comes alive

with the melodious call of birds

in search of a new mate.

But where have these enchanting sounds

been hiding all winter?

For almost 200 species of song birds,

their winters have been spent

down in the tropical climates

of Central and South America.

While this may sound ideal,

it involves one of the most perilous journeys

known in the entire animal kingdom.

This journey is called migration,

and for song birds,

this can involve travelling somewhere

between a few hundred to almost 7,000 miles

in a period of several weeks

to four months.

Birds spend weeks preparing

for the intense journey

by gorging on large quantities of food,

sometimes doubling their weight

prior to departure.

While flying, birds can lose

almost one percent of their body weight an hour,

so packing on the pounds is crucial to their survival.

However, more than the physical stress,

migrating birds are now facing

a new source of hardship:

landscape change.

Just imagine you're the one

getting ready to take a trip.

You've packed the car

with everything you think you need,

fueled up the tank,

eaten a huge breakfast,

and hit the road.

You've taken this journey before.

You know all your favorite rest stops

and little back-alley diners to grab a bite.

Everything is planned out.

But just as your fuel gauge starts

dipping into the red zone,

you pass by what should have been a gas station,

except it's closed.

"Not a problem," you think,

"The next one can't be too far away."

But then that next station never appears.

Unfortunately, as you continue on your route,

the reality of the situation starts to set in.

More and more stations are closed

or just erased from your map.

All of a sudden, your routine trip

has become a desperate search

just to find somewhere safe to rest

and refuel for the night.

This scenario has become the reality

for the majority of migrating song birds

as human land development continues unchecked.

Humans are altering important stop-over sites

that birds have been using for generations.

As migrators pass over the continent,

they run a gauntlet of dangers,

including pesticide ingestion in rural farmlands,

habitat loss in suburban developments,

as well as disorientation from light pollution,

and even structure collision

with tall, reflective glass buildings in cities.

Of the estimated 20 billion individual birds

that comprise the fall population,

only about half will return

to breed the following spring.

Almost one billion of these deaths

are attributed just to building collisions.

With such astounding yearly losses,

humans risk more than just the loss

of the beautiful colors and songs of birds,

they also play an important role in the ecosystem.

Birds help with insect control,

pollination,

and disbursing seeds throughout the landscape.

Without birds, the natural world

would be a very different place.

Although birds face an on-going threat

from human land development,

there are actions that we can all take to help.

Many countries and local governements

have already passed important laws

that restrict the use of poisonous pesticides.

By using more natural, plant-based products,

we can maintain our farms and gardens

without the dangerous side effects.

In addition, as our global populations continue to grow

and people need places to call home,

green spaces can offer both bird habitat

as well as a peaceful and natural place

for us to enjoy.

Small changes at home

can also make a huge difference.

By hanging up feeders

and building bird houses in outdoor areas,

we can provide much-needed food and safety

during long migrations.

Turning out lights in suburban

and urban environments

can also help birds

that look for stars to navigate.

With our help, these sky travellers

can reach their destination safely,

and hopefully keep returning year after year.