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Archive for May, 2015

Educators express concern that today’s kids spend more time looking at digital screens than connecting with nature. Because of the time they spend in the digital world they are comfortable using computers, tablets, cell phones and are skilled in using them. But the natural world is less familiar. Yet, I’m always energized when I lead bird walks for youngsters. Their enthusiasm is contagious. Young boys in particular are fascinated by a bird’s ability to fly. Every nine-year-old boy dreams of flying. He can picture himself flying over his backyard or school. He is a superhero racing through the sky to fight evildoers. “How high can a bird fly?” they pester. “Can they fly over the tree tops? Over skyscrapers? How about mountains, can they fly over mountains? Do birds fly as high as a jet plane?”

            I explain that during their normal day-to-day life, birds generally fly close to the ground, usually less than 50 to 100 feet high. However, during migration, birds fly at higher altitudes because the wind is better. Backyard birds, for example, may fly at 1,000 feet when migrating. Larger birds such as ducks and hawks may fly at an even higher altitude.   And sometimes birds fly incredibly high.

            I ask the boys what is the highest spot on earth. They know. It’s Mount Everest, just over 29,000 feet above sea level, more than 5 miles up. Then I mention that elite mountain climbers attempting to scale Mount Everest have reported seeing flocks of bar-headed geese flying over their heads. Bar-headed geese, slightly smaller than our common Canada geese, have pale white heads with two black horizontal bars. They nest on the Tibetan Plateau, called “the roof of the world,” and migrate annually over the Himalayas to reach their winter territory in south Asia.

            Mountain climbers are skilled athletes who train for months to climb Everest. Yet sometimes it is a struggle for them just to gain a few feet of altitude. The amount of oxygen in the air at 29,000 feet is less than half of what it is at sea level. Climbers refer to it as “thin air,” and it makes it hard to breathe especially when they are exerting tremendous effort to climb. So they bring extra oxygen for climbing at high altitudes. Their Sherpa guides lug hundreds of oxygen tanks up the mountainside so climbers can breathe. Without them, most climbers would never scale Everest. Yet the bar-headed geese just sail gracefully over their heads with no extra oxygen. Cool.

            Airliners cruise at about 30,000 feet. At that height, most people feel the effect of low oxygen. So, to make passengers more comfortable and keep pilots alert and able to function, airlines pressurize a plane’s cabin and add oxygen, simulating conditions at ground level.

            Why do pilots and elite athletes need extra oxygen and geese don’t? Their respiratory system has evolved allowing geese to extract more oxygen from the thin air than humans can. Kids aren’t interested in those technicalities, so I don’t mention it. I want to leave them with the image of sitting on a mountain top and watching birds sail overhead. That is awesome.

            However, there is one element of high altitude flight that I do not fully understand: the outdoor air temperature at 30,000 feet is -35 degrees Fahrenheit. In a plane you can turn up the heat to stay warm. Climbers wear special insulated clothing. But how does a goose stay warm at that temperature? The physical effort required to fly generates body heat and a goose has a thick down coat, but the answer has to be more than that. Maybe someday I will learn the answer. Or, better yet, I’ll just ask a kid if they know. Today’s kids are smart.

            After one recent bird walk when we were back inside the nature center building, one young boy stopped me short saying “Mr. Weber, you were wrong.” That got my attention. “I just Googled it” he said “and it says the bar-headed goose is not the highest flying bird. It’s the Ruppell’s griffin vulture from South Africa. Want to see its picture?”

            I walked over to check his laptop screen. He was right. In the 1970s a Ruppell’s griffin vulture was sucked into the jet engine of a plane flying at 37,000 feet in altitude, more than a mile higher than Mt. Everest.

            Although I was embarrassed that he discovered my error, I was thrilled that he cared enough to Google it. Later, I did my own searching on the internet and learned that other species also fly at high altitudes similar to the bar-headed goose. Most are large African and Asian birds, such as swans and vultures, with very long wings. The highest altitude positively identified for a North American bird was recorded in 1961 over the Nevada desert when a plane collided with a mallard at 21,000 feet.

            Youngsters may spend hours each day looking at digital screens but they still are attracted to the natural world. They have the best of both worlds. Today, if a young boy asks me how high a bird can fly, I still tell him the story of Mt. Everest then add several thousand feet to my previous answer to identify the vulture. Then I explain how he can access the internet with his digital device and discover all kinds of interesting information on his own.

            Learning from kids is just as exciting as teaching them.

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