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Why Do Birds Fly South for the Winter?

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Around this time of year, I always have to take a break from pumpkin planning and marvel at bird migration. How do they find their way around the world without Google Maps? We're not really sure, but research has given us evidence that they use an array of navigation techniques...

1. Migratory reflex and navigational skills appear to be written in the genes. Captive birds have been observed getting pretty fidgety and changing their sleep patterns right before their natural migration time. Ethologists—those who study animal behavior—call the birds' behavior zugunruhe ("migratory restlessness"). Captive birds display zugunruhe even if they're not exposed to natural light or to seasonal temperature changes. Even with the restlessness, many of these birds will orient themselves in the direction that they would normally be traveling at that time of year. Researchers say that the fact that the birds know both when and where to migrate without environmental clues suggests that genes, and a biological calendar written into them, play a role in migration.

2. Genes are all well and good to get them started, but how do birds navigate once they get up in the air? The prevailing theory is that the earth's magnetic field plays a large part. Over the last few years, scientists have discovered tiny bits of magnetite (a magnetic mineral) in the brains of several animal species, including birds, bats, whales and dolphins. The magnetite could enable the animals to use the earth's magnetic fields as a migration guide, but the research is just scratching the surface. Now that we know that birds and other animals could detect magnetic fields and have explored the mechanisms by which they could do it, further research will need to tackle the question of how the animals gather information from the magnetic field, process it and use it to navigate.

3. A particularly cool study showed that migratory birds also use "celestial navigation" to find their way around in the dark. Captive birds placed in a planetarium changed their directional orientation when the star pattern on the ceiling shifted and became confused when the images of stars were dimmed. The scientists conducting the experiment suggest that birds use the layout of constellations in the sky as a compass.

But why migrate in the first place? And why do birds bother flying back north once they've reached a warmer locale? The same reason I have to pull myself away from writing and go to the bodega on the corner: the search for food. While birds might be hard-wired to migrate at certain times of the year, a recent study concluded birds won't make the trip without certain physiological and environmental cues, the most important being the scarcity of food. Birds fly south in the winter in search of alternate food sources, and even though their summer home might be nicer, they return home in the spring when their usual food stocks are replenished. If there's still food to be had at either place, though, some birds will delay migration or won't bother leaving at all, choosing instead to band together in flocks to forage.

This article originally appeared last fall.

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10 Memorable Neil deGrasse Tyson Quotes
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Neil deGrasse Tyson is America's preeminent badass astrophysicist. He's a passionate advocate for science, NASA, and education. He's also well-known for a little incident involving Pluto. And the man holds nearly 20 honorary doctorates (in addition to his real one). In honor of his 59th birthday, here are 10 of our favorite Neil deGrasse Tyson quotes.

1. ON SCIENCE

"The good thing about science is that it's true whether or not you believe in it."
—From Real Time with Bill Maher.

2. ON NASA FUNDING

"As a fraction of your tax dollar today, what is the total cost of all spaceborne telescopes, planetary probes, the rovers on Mars, the International Space Station, the space shuttle, telescopes yet to orbit, and missions yet to fly?' Answer: one-half of one percent of each tax dollar. Half a penny. I’d prefer it were more: perhaps two cents on the dollar. Even during the storied Apollo era, peak NASA spending amounted to little more than four cents on the tax dollar." 
—From Space Chronicles

3. ON GOD AND HURRICANES

"Once upon a time, people identified the god Neptune as the source of storms at sea. Today we call these storms hurricanes ... The only people who still call hurricanes acts of God are the people who write insurance forms."
—From Death by Black Hole

4. ON THE BENEFITS OF TECHNOLOGY INVENTED FOR USE IN SPACE

"Countless women are alive today because of ideas stimulated by a design flaw in the Hubble Space Telescope." (Editor's note: technology used to repair the Hubble Space Telescope's optical problems led to improved technology for breast cancer detection.)
—From Space Chronicles

5. ON THE DEMOTION OF PLUTO FROM PLANET STATUS 

PBS

"I knew Pluto was popular among elementary schoolkids, but I had no idea they would mobilize into a 'Save Pluto' campaign. I now have a drawer full of hate letters from hundreds of elementary schoolchildren (with supportive cover letters from their science teachers) pleading with me to reverse my stance on Pluto. The file includes a photograph of the entire third grade of a school posing on their front steps and holding up a banner proclaiming, 'Dr. Tyson—Pluto is a Planet!'"
—From The Sky Is Not the Limit

6. ON JAMES CAMERON'S TITANIC

"In [Titanic], the stars above the ship bear no correspondence to any constellations in a real sky. Worse yet, while the heroine bobs ... we are treated to her view of this Hollywood sky—one where the stars on the right half of the scene trace the mirror image of the stars in the left half. How lazy can you get?"
—From Death by Black Hole

7. ON DEATH BY ASTEROID

"On Friday the 13th, April 2029, an asteroid large enough to fill the Rose Bowl as though it were an egg cup will fly so close to Earth that it will dip below the altitude of our communication satellites. We did not name this asteroid Bambi. Instead, we named it Apophis, after the Egyptian god of darkness and death."
—From Space Chronicles

8. ON THE MOTIVATIONS BEHIND AMERICA'S MOONSHOT

"[L]et us not fool ourselves into thinking we went to the Moon because we are pioneers, or discoverers, or adventurers. We went to the Moon because it was the militaristically expedient thing to do."
—From The Sky Is Not the Limit

9. ON INTELLIGENT LIFE (OR THE LACK THEREOF)

Perhaps we've never been visited by aliens because they have looked upon Earth and decided there's no sign of intelligent life.
Read more at: https://www.brainyquote.com/quotes/quotes/n/neildegras615117.html
Perhaps we've never been visited by aliens because they have looked upon Earth and decided there's no sign of intelligent life.
Read more at: https://www.brainyquote.com/quotes/quotes/n/neildegras615117.html

"Perhaps we've never been visited by aliens because they have looked upon Earth and decided there's no sign of intelligent life."

10. PRACTICAL ADVICE IN THE EVENT OF ALIEN CONTACT 

A still from Steven Spielberg's E.T. the Extra-Terrestrial
Universal Studios
"[I]f an alien lands on your front lawn and extends an appendage as a gesture of greeting, before you get friendly, toss it an eightball. If the appendage explodes, then the alien was probably made of antimatter. If not, then you can proceed to take it to your leader."
—From Death by Black Hole
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40 Fun Facts About Sesame Street
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Now in its 47th season, Sesame Street is one of television's most iconic programs—and it's not just for kids. We're big fans of the Street, and to prove it, here are some of our favorite Sesame facts from previous stories and our Amazing Fact Generator.

Sesame Workshop

1. Oscar the Grouch used to be orange. Jim Henson decided to make him green before season two.

2. How did Oscar explain the color change? He said he went on vacation to the very damp Swamp Mushy Muddy and turned green overnight.

3. During a 2004 episode, Cookie Monster said that before he started eating cookies, his name was Sid.

4. In 1980, C-3PO and R2-D2 visited Sesame Street. They played games, sang songs, and R2-D2 fell in love with a fire hydrant.

5. Mr. Snuffleupagus has a first name—Aloysius

6. Ralph Nader stopped by in 1988 and sang "a consumer advocate is a person in your neighborhood."

7. Caroll Spinney said he based Oscar's voice on a cab driver from the Bronx who brought him to the audition.

8. In 1970, Ernie reached #16 on the Billboard Hot 100 with the timeless hit "Rubber Duckie."

9. One of Count von Count's lady friends is Countess von Backwards, who's also obsessed with counting but likes to do it backwards.

10. Sesame Street made its Afghanistan debut in 2011 with Baghch-e-Simsim (Sesame Garden). Big Bird, Grover and Elmo are involved.

11. According to Muppet Wiki, Oscar the Grouch and Count von Count were minimized on Baghch-e-Simsim "due to cultural taboos against trash and vampirism."

12. Before Giancarlo Esposito was Breaking Bad's super intense Gus Fring, he played Big Bird's camp counselor Mickey in 1982.

13. Thankfully, those episodes are available on YouTube.

14. How big is Big Bird? 8'2". (Pictured with First Lady Pat Nixon.)

15. In 2002, the South African version (Takalani Sesame) added an HIV-positive Muppet named Kami.

16. Six Republicans on the House Commerce Committee wrote a letter to PBS president Pat Mitchell warning that Kami was not appropriate for American children, and reminded Mitchell that their committee controlled PBS' funding.

17. Sesame Street's resident game show host Guy Smiley was using a pseudonym. His real name was Bernie Liederkrantz.

18. Bert and Ernie have been getting questioned about their sexuality for years. Ernie himself, as performed by Steve Whitmere, has weighed in: “All that stuff about me and Bert? It’s not true. We’re both very happy, but we’re not gay,”

19. A few years later, Bert (as performed by Eric Jacobson) answered the same question by saying, “No, no. In fact, sometimes we are not even friends; he can be a pain in the neck.”

20. In the first season, both Superman and Batman appeared in short cartoons produced by Filmation. In one clip, Batman told Bert and Ernie to stop arguing and take turns choosing what’s on TV.

21. In another segment, Superman battled a giant chimp.

22. Telly was originally "Television Monster," a TV-obsessed Muppet whose eyes whirled around as he watched.

23. According to Sesame Workshop, Elmo is the only non-human to testify before Congress.

24. He lobbied for more funding for music education, so that "when Elmo goes to school, there will be the instruments to play."

25. In the early 1990s, soon after Jim Henson’s passing, a rumor circulated that Ernie would be killed off in order to teach children about death, as they'd done with Mr. Hooper.

26. According to Snopes, the rumor may have spread thanks to New Hampshire college student, Michael Tabor, who convinced his graduating class to wear “Save Ernie” beanies and sign a petition to persuade Sesame Workshop to let Ernie live.

27. By the time Tabor was corrected, the newspapers had already picked up the story.

28. Sesame Street’s Executive Producer Carol-Lynn Parente joined Sesame Workshop as a production assistant and has worked her way to the top.

29. Originally, Count von Count was more sinister. He could hypnotize and stun people.

30. According to Sesame Workshop, all Sesame Street's main Muppets have four fingers except Cookie Monster, who has five.

31. The episode with Mr. Hooper's funeral aired on Thanksgiving Day in 1983. That date was chosen because families were more likely to be together at that time, in case kids had questions or needed emotional support.

32. Mr. Hooper’s first name was Harold.

33. Big Bird sang "Bein' Green" at Jim Henson's memorial service.

34. As Chris Higgins put it, the performance was "devastating."

35. Oscar's Israeli counterpart is Moishe Oofnik, whose last name means “grouch” in Hebrew.

36. Nigeria's version of Cookie Monster eats yams. His catchphrase: "ME WANT YAM!"

37. Sesame's Roosevelt Franklin ran a school, where he spoke in scat and taught about Africa. Some parents hated him, so in 1975 he got the boot, only to inspire Gob Bluth’s racist puppet Franklin on Arrested Development 28 years later.

38. Our good friend and contributor Eddie Deezen was the voice of Donnie Dodo in the 1985 classic Follow That Bird.

39. Cookie Monster evolved from The Wheel-Stealer—a snack-pilfering puppet Jim Henson created to promote Wheels, Crowns and Flutes in the 1960s.

40. This puppet later was seen eating a computer in an IBM training film and on The Ed Sullivan Show.

Thanks to Stacy Conradt, Joe Hennes, Drew Toal, and Chris Higgins for their previous Sesame coverage!

An earlier version of this article appeared in 2012.

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