Most birds produce short, simple calls, but songbirds also have the ability of many complex vocal (发声的) patterns that help them attract mates, defend territory (领地), and strengthen their social bonds. Each songbird species has its own unique song patterns, some with characteristic regional dialects. Experienced listeners can even distinguish individual birds by their unique songs.

    A lot of what scientists know about bird song comes from studying zebra finches. A baby male zebra finch typically learns to sing from its father or other males, starting while it's still a baby bird in the nest. First comes the sensory learning stage, when the baby finch hears the songs sung around it and commits them to memory. The bird starts to vocalize during the motor learning stage, practicing until it can match the song it memorized. As the bird learns, hearing the tutor's song over and over again is helpful — up to a point. If it hears the song too many times, the imitation (模仿) becomes worse -- and the source matters. If the song is played through a loudspeaker, he can't pick it up as easily. But hide the same loudspeaker inside a toy painted to look like a zebra finch, and his learning improves.

    What if the baby never hears another zebra finch's song? Interestingly enough, it'll sing anyway. Isolated finches still produce what are called innate songs or isolate songs. A specific tune might be taught, but the instinct to sing seems to exist in a songbird's brain. Innate songs sound different from the “cultured” songs learned from other finches - at first. If isolate zebra finches start a new colony, the young birds pick up the isolate song from their fathers. But the song changes from generation to generation. And after a few generations, the melody actually starts to resemble the cultured songs sung by zebra finches in the wild.

    A great woman once said, “Women must try to do things as men have tried. When they fail, their failure must be a challenge to others. “These are the words of US pilot Amelia Earhart（1897- 1937）, a pioneer in aviation（航空领域）, who was the first woman to fly across the Atlantic Ocean

    Her story ended in mystery when she disappeared without a trace（踪迹）during a flight over the Pacific Ocean. Theories about what happened to Earhart were proposed, but nothing was ever confirmed—until now. A study published in March conducted by Richard Jantz from the University of Tennessee, US, determined that bones found in 1940 on a remote Pacific island belonged to Earhart. Following the discovery, the world's memories of the legendary female pilot were brought back to life.

    Earhart was born in 1897. When she was young, she was very interested in stories about women who were successful in male-dominated（男性为主的）professions, such as engineering and law. But in 1920, Earhart's life changed after her first experience of being a plane passenger. As soon as the plane left the ground, Earhart knew that she loved flying, so she found herself a teacher and started to learn how to fly for herself. To pay for the lessons and buy a plane of her own, she took all sorts of jobs.

    In 1932, Earhart flew solo（独自地）across the Atlantic, becoming the first woman ever to do so. She also designed a flying suit for women and went on to design other clothes for women who led active lives. When she was nearly 40, Earhart was ready for a final challenge—to be the first woman to fly around the world. Her first attempt was unsuccessful but she tried again in 1937 with her navigator（领航员）Fred Noonan. But one month later, they disappeared in bad weather in mid-flight.

    Even though it's still not clear how she ended up on the island, we're one step closer to finding the answer. And no matter what, Earhart will be forever remembered as a brave pioneer, both as a pilot and as a woman.

    Some of the world's most significant problems never hit headlines. One example comes from agriculture. Food riots（暴动）and hunger make news. But the trend lying behind these matters is rarely talked about. This is the decrease in the growth in production of some of the world's major crops. A new study by the University of Minnesota and McGill University in Montreal looks at where, and how far, this decline is occurring.

    The authors take a vast number of data points for the four most important crops: rice, wheat, corn and soyabeans. They find that on between 24% and 39% of all harvested areas, the improvement inproduction that took place before the 1980s slowed down in the 1990s and 2000s.

    There are two worrying features of the slowdown. One is that it has been particularly sharp in the world's most populous countries, India and China. Their ability to feed themselves has been an important source of relative stability both within the countries and on world food markets. That self-sufficiency (自给自足) cannot be taken for granted if productions continue to slow down.

    Second, production growth has been lower in wheat and rice than in corn and soyabeans. This is problematic because wheat and rice are more important as foods, accounting for around half of all calories consumed. Corn and soyabeans are more important as feed grains. The authors note that "we have preferentially focused our crop improvement efforts on feeding animals and cars rather than on crops that feed people and are the basis of food security in much of the world."

    The report also states the more optimistic findings of another new paper which suggests that the world will not have to dig up a lot more land for farming in order to feed 9 billion people in 2050, as the Food and Agriculture Organisation has argued.

    Instead, it says, thanks to slowing population growth, land currently ploughed（犁）up for crops might be able to revert (回返) to forest or wilderness. This could happen. The trouble is that the prediction assumes continued improvements in productions, which may not actually happen.

    When I was a kid, I loved reading history, science fiction, detective stories, but especially comics. I had piles of them and kept talking my Dad into making more shelves for me. One day, I read about a 13-year-old boy who had actually written one of my favorite comics, Legion of Super-Heroes, and I said, “I can do that too.” That year, I was two years younger than the writer.

    Three years later, a friend and I started our own fan magazine about comics. It became the first place that regularly told people when their favorite comics were coming out and writers and artists were working on them. Because of the magazine, I won the awards for The Comic Reader, but more important, it got many of the people in the field to know who I was.

    One day when I was visiting DC Comics for news for my next issue, one of the editors a chance to write text for his comic. Suddenly, at 16, I was getting paid to write.

    I was able to pay for my college classes working as an assistant editor at DC Comics and learned how to write comics stories while I was there. I wrote hundreds of stories. Over the years, I worked as an editor and an executive (主管) for the company, eventually serving as a president and publisher, until earlier this year. Now I'm back to my first love, writing comics again.

    Every morning, I open my e-mail and find pages of art sent in by artists across the country who draw my stories. When I'm tired of working on the stories, I can go online and find my readers commenting on my stories or telling me when I make mistakes.

    Keep reading and writing, it's a wonderful way to live.

Flying High

    Barrington Irving landed his record-breaking light at age 23 and founded an educational nonprofit organization. His message for kids: "The only thing that separates you from scientists is determination, hard work and a strong liking for what you want to achieve." The secret, he believes, is having a dream in the first place.

    The moment of inspiration for Irving came at the age of 15 in his parents' bookstore. One customer, a professional pilot, asked Irving if he'd thought about becoming a pilot. "I told him I didn't think I was smart enough; but the next day he took me to the cockpit (驾驶舱) of the commercial airplane he flew and just like that I was hooked."

    To follow his dream, Irving Turned down a football scholarship to the University of Florida. He washed airplanes to earn money for a flight school and increased his flying skills by practicing at home on a $40 flight simulator (模拟) video game. Then another dream took hold: flying alone around the world. He faced more than 50 rejections for sponsorship before convincing some companies to donate aircraft components. He took off with no weather radar, no de-icing system, and just $30 in his pocket.

    After 97 days, 26 stops and dozens of thunderstorms, he touched down to a cheering crowd in Miami. "It was seeing so many young people watching and listening that pushed me into giving back with my knowledge an experience." Irving has been doing it ever since. He set up his non-profit organization, Experience Aviation (航空), aiming to increase the numbers of youth in aviation career. By bring challenging project-based learning, hands-on and other educational opportunities to school districts and local communities nationwide, the organization has excited the hearts and minds of youth. "We want to create chances for students to accomplish something amazing," he notes. Perhaps Irving's most powerful educational tool is the example his own life provides.

Freshmen at Central Valley High in Ceres had a busy week of good deeds, tied to Pay It Forward Day, April 30, and an urge to show the world that teens can be awesome.

Kids in Success 101 spent first period making sandwiches for the homeless. The classes, taught by Natalie Rowell and Becky Lynch, got to hand 200 bagged sandwiches to the charity giving out the food. "They got to really see what an impact they had. It was inspiring and heartwarming," Rowell said. Besides, students also made blankets to send to soldiers, and created 45 flower arrangements for senior people at the Hale Aloha Home in Ceres. "They were nervous going into it. But when they saw how happy the elderly were, the reality of what they did really surfaced," Rowell said.

Rowell said she liked working with children. get to see how they learn. "It's different from how we learn, but we're kind of the same because they struggle in some of the subjects that we find hard as well."

Success 101 was tailor-made for students with that kind of insight. The first-period class includes study help, speakers on teen subjects and an overall focus on looking past high school, figuring out the steps to create their future. "Some kids need that little push. In this class, that's what we do, we give them that little push," Lynch added. "Success would be beneficial for all ninth-grade students. Since the start of the year, I really see a change in them."

Raquel Alfaro, a teen participant who worked with the younger kids, likes the Pay It Forward idea. "This helps us show adults, and also kids, that we're doing something different and that we're not as mean and selfish as they think we are," Alfaro said.