Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all, you probably sing or whistle when you are happy.

    Some scientists believe that birds do sing some of the time just because they are happy. However, they sing most of the time for a very different reason. Their singing is actually a warning to other birds to stay out of their territory.

    Do you know what a “territory” is? A territory is an area that an animal, usually the male, claims（声称）as its own. Only he and his family are welcome there. No other families of the same species are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout. Probably this would be enough to frighten him away.

    If so, you have actually scared the stranger away without having to fight him. A bird does the same thing. But he expects an outsider almost any time, especially at nesting（筑巢）season. So he is screaming all the time, whether he can see an outsider or not. This screaming is what we call a bird's song, and it is usually enough to keep an outsider away.

    Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

    You can see that birds have a language of their own. Most of it has to do with attracting mates and setting up territories.

    At least 40% of Australian households now have at least one home “Internet of Things” device. These are fridges, window blinds, locks and other devices that are connected to the Internet.

    While the Internet of Things (IoT) may lead to more efficiency in our daily lives, my research shows that consumers are exposed to many risks by the use of IoT devices, ranging from disclosure of private information, to physical injury and problems with the devices themselves.

    Australia has no specific laws aimed at addressing IoT issues, and current laws intended to protect consumers have gaps and uncertainties when dealing with IoT devices. Many IoT device manufacturers and suppliers show little regard for customers' privacy. Some even make money from customer data.

    Consumer electronics company Vizio recently agreed to pay US regulators US $ 2.2 million, after failing to get appropriate permission from users to track their TV viewing habits.

    Late last year, the Norwegian Consumer Council found that a children's doll recorded anything said to it by children and sent the recordings to a US company. The company reserved the right to share and use the data for a broad range of purposes.

    IoT devices have the potential to collect more private data about individuals than was possible with previous devices. All this data can then be used to study consumers, predict our behavior, and sell us products at times when our willpower is lowest. Some companies are currently using technology to track consumers through stores and send their messages to mobile phones. This may be linked to our purchase history.

    Consumers are exposed to significant risks from IoT devices, from the use of data, to security flaws and devices no longer being supported. They should think long and hard about the risks they are taking on with IoT devices. Do you really need that internet-connected hairbrush?

    One day a mime(哑剧演员) is visiting the zoo and tries to earn some money as a street performer. As soon as he starts to draw a crowd, a zookeeper pulls him into his office. The zookeeper explains that the zoo's most popular attraction, a gorilla(大猩猩), has died suddenly and the keeper fears that attendance(出席人数) at the zoo will fall off. He offers the mime a job to dress up as the gorilla. The mime accepts.

    The next morning the mime puts on the gorilla suit and enters the cage before the crowd comes. He soon discovers he can sleep, play and make fun of people and he draws bigger crowds than he ever did as a mime — the job he likes but loses.

    However, with days going by, he begins to notice that the people are paying more attention to the lion in the cage next to his. Not wanting to lose the attention of his audience, he climbs to the top of his cage, crawls across a partition(隔墙), and dangles(悬挂) from the top to the lion's cage. The lion gets angry at this. The scene is a fuel to the crowd.

    At the end of the day he is given a raise for being such a good attraction — well, this continues for some time. The crowds grow larger, and the mime's pay keeps going up.

    Then one day when he is dangling over the lion he slides and falls. The mime is terrified. He starts screaming “Help me!”, but the lion is quick. The mime soon finds himself flat on his back looking up at the angry lion and the lion says, “Shut up you fool! Do you want to get us both fired?”

    In beautiful rural Montana lies the town of Livingston. Around half the students in the Livingston School District qualify for free or reduced-price lunches, according to local educator Rachael Jones, known as "Farmer Jones". She is the director of the Livingston Farm to School program, which uses the district's two greenhouses and four gardens to grow food that supplements school meals while offering kids hands-on lessons. Jones said, "In many places around the country, if you can't pay for your school meal, you don't eat. Well, here, we don't turn anyone away."

    The town's school district and community members started the program eight years ago. It's part of the National Farm to School Network, which aims to increase access to local food and nutrition education across the country. Jones, who attended public school in Livingston as a kid, has headed up the local program since 2014. Farm to School enriches curriculums in all of the schools through garden lessons, cafeteria and kitchen lessons, and classroom lessons.

    Research has shown that healthy school meals can enhance academic performance, including improved test scores. Though the Farm to School program is not aimed solely at lower-income students, Jones said, "Such kids are more likely to eat lunch provided by the school. Eventually she wants to get healthy, affordable meals on the plate of every child in Livingston.

    It is important for kids to understand where their food comes from. That's a life changing experience for them. Jones said," When I grew up a big force in my life was my grandma Ethel. She taught me from a really early age the value of growing my own food. I worked in her gardens with her and somehow, through all of those experiences —eating her tomatoes and canning pickles with her —it really built up my trust and knowledge in food systems. I'm so thankful for her!"

    When Joanne Morton and Lydia Shaw came across the Boston Public Market, which features only New England businesspersons, they knew they had to stop in. The women, visiting from southeastern Connecticut, always try to buy local. "We always try to support our local farmers and businessmen," says Ms. Shaw. "We're not into big companies," adds Ms. Morton.

    They aren't alone. A great number of Americans continue to be attracted by "local" food and to buy it, according to recent surveys from the International Food Information Council Foundation, the Pew Research Center, and British polling firm Ipsos. But what does it mean to shop local? For some, local is still a matter of geography. For others, it is about supporting their local economy (经济). And for still others, it is about knowing where their food comes from and how it is made, even if it is coffee shipped from a Costa Rican company. In 2008, Congress passed a bill that gave money to support local food. According to the Food, Conservation, and Energy Act, a product that can be considered local has to travel less than 400 miles.

    But Lydia Zepeda, a professor at the University of Wisconsin-Madison, has found the largest agreement about what is local is any product that comes from within an hour's drive. "But is that with or without traffic?" She asks. "What if it crosses state lines?" adds John Hayes, a food science professor at Pennsylvania State University. "A customer might like to buy local to help an old town," he says. "Or maybe it's just because local food tastes better." It is for Kaitlin Bohon. "I taste a difference," she says at the Boston Public Market. For Ms. Bohon, buying local is both about supporting New England business and knowing who grew and handled her food.

    Central Park

    Explore Central Park, one of the largest city parks in the world and one of the most famous symbols of New York. Let's have a look at its main sights.

    Central Park is New York's largest city park and one of the biggest in the world, with an area of 843 acres (about 3.4km²). This park is home to man-made lakes, waterfalls, grass and wooded areas. You will also find the Central Park Zoo, among other attractions in this greenspace of New York.

    Besides being the city's primary green lungs, Central Park is also a favorite spot for many New Yorkers. It is perfect for sunbathing, going for walks, or doing any outdoor sports. Something that we found curious is seeing so many people running with their babies in prams (婴儿车).

    On Foot or by Bicycle

    To get to know some of the wildest parts of Central Park we suggest walking. However, to get a general feel for the whole park, the best thing to do is hire a bicycle and enjoy the scenery.

    If you decide to hire a bike, you will find lots of bike rental stores around Central Park that are not very expensive.

    Open Time

    From 7 a.m. to 10 p.m. on weekends.

    From 6 a.m. to 8:30 p.m. on weekdays.

    Price

    Entry to the Park is free. But if you visit some parts like Central Park Zoo, you need to buy a ticket.

    Transport

    Subway: Line 5, 6, 7, A, B, C and D.

    Bus: Line M1, M2, M3, M4 and M10.

    Nearby places

    Metropolitan Museum of Art (447 m)

    Guggenheim Museum (564 m)

    American Museum of Natural History (688 m)

    Whitney Museum of American Art (1 km)

    The Frick Collection (1.3 km)