Bird migration, a perilous journey - Alyssa Klavans

252,715 views ・ 2013-09-17

TED-Ed


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Each spring, nature lovers eagerly greet the signs
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that winter is finally coming to an end.
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As the days grow warmer,
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the flowers and trees start to bloom,
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and the world comes alive
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with the melodious call of birds
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in search of a new mate.
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But where have these enchanting sounds
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been hiding all winter?
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For almost 200 species of song birds,
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their winters have been spent
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down in the tropical climates
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of Central and South America.
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While this may sound ideal,
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it involves one of the most perilous journeys
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known in the entire animal kingdom.
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This journey is called migration,
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and for song birds,
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this can involve travelling somewhere
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between a few hundred to almost 7,000 miles
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in a period of several weeks
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to four months.
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Birds spend weeks preparing
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for the intense journey
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by gorging on large quantities of food,
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sometimes doubling their weight
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prior to departure.
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While flying, birds can lose
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almost one percent of their body weight an hour,
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so packing on the pounds is crucial to their survival.
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However, more than the physical stress,
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migrating birds are now facing
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a new source of hardship:
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landscape change.
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Just imagine you're the one
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getting ready to take a trip.
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You've packed the car
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with everything you think you need,
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fueled up the tank,
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eaten a huge breakfast,
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and hit the road.
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You've taken this journey before.
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You know all your favorite rest stops
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and little back-alley diners to grab a bite.
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Everything is planned out.
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But just as your fuel gauge starts
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dipping into the red zone,
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you pass by what should have been a gas station,
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except it's closed.
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"Not a problem," you think,
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"The next one can't be too far away."
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But then that next station never appears.
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Unfortunately, as you continue on your route,
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the reality of the situation starts to set in.
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More and more stations are closed
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or just erased from your map.
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All of a sudden, your routine trip
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has become a desperate search
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just to find somewhere safe to rest
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and refuel for the night.
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This scenario has become the reality
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for the majority of migrating song birds
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as human land development continues unchecked.
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Humans are altering important stop-over sites
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that birds have been using for generations.
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As migrators pass over the continent,
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they run a gauntlet of dangers,
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including pesticide ingestion in rural farmlands,
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habitat loss in suburban developments,
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as well as disorientation from light pollution,
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and even structure collision
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with tall, reflective glass buildings in cities.
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Of the estimated 20 billion individual birds
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that comprise the fall population,
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only about half will return
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to breed the following spring.
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Almost one billion of these deaths
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are attributed just to building collisions.
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With such astounding yearly losses,
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humans risk more than just the loss
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of the beautiful colors and songs of birds,
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they also play an important role in the ecosystem.
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Birds help with insect control,
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pollination,
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and disbursing seeds throughout the landscape.
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Without birds, the natural world
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would be a very different place.
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Although birds face an on-going threat
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from human land development,
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there are actions that we can all take to help.
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Many countries and local governements
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have already passed important laws
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that restrict the use of poisonous pesticides.
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By using more natural, plant-based products,
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we can maintain our farms and gardens
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without the dangerous side effects.
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In addition, as our global populations continue to grow
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and people need places to call home,
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green spaces can offer both bird habitat
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as well as a peaceful and natural place
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for us to enjoy.
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Small changes at home
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can also make a huge difference.
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By hanging up feeders
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and building bird houses in outdoor areas,
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we can provide much-needed food and safety
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during long migrations.
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Turning out lights in suburban
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and urban environments
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can also help birds
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that look for stars to navigate.
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With our help, these sky travellers
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can reach their destination safely,
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and hopefully keep returning year after year.
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