I'd planned to spend my weekend in the sun, potting flowers outdoors. But that was before the pair of crows (乌鸦). Out of nowhere, they had set up their base camp in our backyard.

    We first discovered our feathered enemies on Friday morning. It was early, and the sound the birds made traveled through our neighborhood. I figured they'd go away soon. But, no. They were getting louder and probably annoying my neighbors nearly as much as us with the noise. I admit I got a little desperate.

    Then, on Sunday afternoon, I looked out the kitchen window to see our dog Quatchi staring at something on the ground. I went to explore and found a small coal-black bird in the grass. Its eyes were milky, and it stayed perfectly still as my dog inched towards it. Only when Quatchi touched his nose to its head did it walk away. I took hold of the dog and locked him inside and came back with my camera.

    It never occurred to me that the young would be hanging out on the ground, growing and gaining strength as its parents guarded it from above. The second I saw this little creature I forgave the crows.

    To be honest, I've never been much of a bird person. I also have a healthy respect for birds, and by healthy I mean slightly fear-based. They're basically living dinosaurs.

    I wish they'd chosen another backyard. There are only so many sunny days in Seattle, and I still can't do any gardening out there. But I'm also grateful that I got to see this little bit of nature unfold up close. It's pretty amazing.

    The experience has also strengthened my desire to create a beautiful backyard garden that attracts lots of bees, butterflies, and yes, birds. They are welcome here.

    Even if trees cannot walk, they are still on the move.

    In parts of the Arctic, entire forests are moving northward. Across the Arctic, temperatures are rising faster than anywhere else in the world. As that happens, the tree line that marks where forests stop and the treeless tundra(冻土地带) starts has been shifting northward. Trees growing along the tree line must protect themselves from the cold wind. To do this, plants tend to grow horizontal(水平的) branches low to the ground. The energy it takes for trees to grow this way means they don't have enough energy to make seeds.

    But as Earth's climate has been warming, trees no longer have to just grow horizontally. Many can instead grow up toward the sky. This takes less energy. And with all the leftover energy. these trees have started producing more seeds. This happens especially in places where the white spruce(白云杉) grows.

    White spruce, which is a North American tree, is quite able to produce a lot of seeds, which can move long distances in the wind. When wind-blown seeds end up on the tundra beyond the tree line, they eventually can sprout(发芽) new trees. This explains how a forest can move. Of course, the process would work only if the tundra were warm enough. But in recent years, the whole planet has been warming.

    New trees will provide shelters for some snow, keeping the sun's rays from making the white surface disappear. Instead, the trees absorb the sun's heat. This warms the surrounding air. The extra warmth encourages even more trees to produce seeds. That further boosts a forest's ability to expand. In addition, more trees will trap more snow, preventing much of it from being blown away. Snow can trap heat in the soil below, which encourages trees to grow. The recent rise of temperature has helped more trees grow. The recent rise of temperatures has helped more trees grow past the tree line. People worry about impacts on the animals that depend on frozen conditions for food and shelter.

    When I was trying to find a place where to spend my December holidays, I met by chance some cheap flights to Iceland. After checking just a few winter pictures of Iceland, I realized that the country, known as the land of fire and ice, during the cold months of the year could offer me experiences I had never had before.

    For sure you can't miss the chance to go to Iceland in winter if your traveling wish list includes at least one of the crazy experiences Iceland can offer. Iceland in the North

    Atlantic Ocean is a paradise ( 乐 园 ) for all those who want to see the northern lights, experience cold weather conditions and put themselves in geothermal ( 地 热 的 ) baths while the snow is falling on their head.

    The best way to move around Iceland is with a rental car. Distances are huge and public transport in winter is not really common out of the major towns. As we wanted to be even more convenient we decided to rent a small camper ( 野 营 车 ). Sleeping and cooking in a camper saved us a lot of driving, money and gave us the chance to be always in the right place at the right time.

    There were also no locals and in many cases no tourist facilities (设备). For us, as we slept in a camper, it was easier. But for tourists traveling by normal cars it is necessary to check the opening times of hotels and restaurants as many of them run just from June to September.

    It is amazing to experience how the weather is changing in Iceland. However, Icelanders prefer to stay inside their houses. They have even no time to complain about the weather in December. All they care about is Christmas. They love to decorate their houses, sing Christmas songs and eat typical Christmas food.

    Edward Hibberd Johnson was an American inventor. He lived in New York City in the 1800s. In 1882, Johnson had an idea. It would change the look of Christmas forever.

    Johnson worked as a boss at a technology company. In 1871, he hired a young man to work for him. The man's name was Thomas Edison. Edison was a great worker. He came up with many new ideas. Later, Edison left to start his own company. Johnson followed him. Johnson started turning Edison's ideas into money. In 1880, Edison invented the light bulb. No one knew how much it was worth. At the time, most homes did not have the electricity to power it. However, Johnson helped start a company to sell the bulbs.

    Before long, Mr. Johnson had a bright idea. Christmas trees were very popular. They were so beautiful because of their candles. Flickering (闪烁的) flames were perfect for Christmas. But they were also dangerous. They could easily start a fire.

    Mr. Johnson thought of a way to fix this. He set up a Christmas tree by one of his windows. Then he took 80 colored light bulbs and hung them around it. The lights were red, white and blue. People on the street stopped to look. They admired the shining Christmas tree. It was so popular that Johnson made it a tradition. Each year he added more lights. In 1884, there were 120 light bulbs on his tree. The lights were not cheap. In 1900, a string of 16 bulbs cost $12. That was a lot of money back then, because people made less. In today's money, that is about $350. But over time, they started to cost less. By the 1930s, colored light bulbs were everywhere.

    Today millions of light sets are sold in America each year. They light 80 million homes. Some of them are now used for other holidays too. They are used on Halloween and Valentine's Day. But it all started with Johnson's Christmas tree.

We are what we eat. That is an old expression, but one worth knowing. A recent look at diets around the world shows that people who eat healthy food—and not too much of it—live longer. But which areas of the world have the best diets？Researchers found that foods in some of the healthiest diets—Mediterranean, New Nordic, Japanese and French—may be very different, but they are all heavy on local, seasonal and limit processed foods, which are high in vegetables and seafood and low in red meat.

Mediterranean diet contains lots of fruits, vegetables, whole grains, nuts and olive oil. The diet has proper amounts of fish and poultry (禽肉). Red meat and foods high in sugar and salt are not big parts of this diet.

New Nordic diet has whole grains like oats and rye, vegetables such as carrots, broccoli and eggs, seafood, fruits, oil, low­fat milk and cheese. Very sugary desserts are not common in this diet.

Japanese people are some of the longest­living people on the planet, with women up to 87 years old and men up to 80. The Japanese diet is the reason for such lengths of life. The diet has many foods that are low in calories and high in nutrients. Japanese people eat a lot of seaweed, tofu, rice, vegetables and fish. The tradition there is to stop eating when your stomach feels 80 percent full.

However, French people eat fatty foods but do not get fat. And they live a long time. This phenomenon is called the "French Paradox". The reason why the French eat fatty foods without getting fat may be simple. They eat less. Serving sizes in French restaurants and in products sold in stores are smaller than those in most countries. And generally speaking, most French people do not snack. This means they do not eat food between meals.