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TANGENTS

Rare to Extinct

BYIHTISHAM KABIR
Scientists estimate that 133 bird species have become extinct worldwide since 1500, 103 of them since 1800. There are many famous birds among them, including the Dodo, the Great Auk, the Pink-headed Duck and the Passenger Pigeon.
The Dodo was a native of Mauritius where it existed in peace for so long that it lost its ability to fly. Thus it was in trouble when Portuguese sailors - the first humans on that island - landed there. The settlers found a convenient source of nutrition in the Dodo, decimating it over the years. The last Dodo bird was killed in 1681.
Passenger Pigeons in North America were once prolific. Gigantic flocks of them, perhaps in the millions, flew together like a black cloud covering the sky. The great ornithologist John James Audobon witnessed one such flock in Ohio in 1813. The flock flew at over sixty miles per hour and the sky darkened suddenly like in an eclipse when it arrived. An estimated two billion Passenger Pigeons lived in North America during that time.
However, they decreased as the growing European population in America hunted them for food. The giant flocks of Passenger Pigeons were shredded into smaller groups which could not protect themselves from humans and other predators.
The last Passenger Pigeon in the wild was a female, shot by a fourteen-year-old boy in Ohio on March 24, 1900. Some remained in captivity but none bred. Today only dead ones can be found in museums.
The Great Auk was a large flightless bird of the North Atlantic islands. It became extinct in 1844 due to hunting by humans. When it became rare, museum directors, anticipating their disappearance, raced to collect their body parts. The last few Great Auks were thus captured and killed by the agents of museums.
The most interesting part about the Great Auk was its egg. Sought after by collectors, it was shaped like a top to prevent rolling off the top of cliffs where the bird dwelled. Its beige shell was marked by a unique, intricate pattern resembling calligraphy. Some speculate that parent Auks could recognize their own egg from those of other parents based on this calligraphy.
Driving a species to its extinction is tragic, but it also has unintended consequences. For example, there is a species of tree in Mauritius that lives up to 300 years. But ever since the Dodo disappeared, no new seedling has appeared and the last of its breed
are dying. Apparently the Dodo ate the fruit of this tree, and the seed somehow fertilized while passing through the digestive system of the Dodo.
While about two dozen species of birds have been extirpated from Bangladesh (that is, they were once here, but no more), only one of our birds, the legendary Pink-headed Duck, has become globally extinct. (Why is it that bird species become famous after they have become extinct?) A common bird of my childhood, the White-rumped Vulture, is now rare and considered "Critically Endangered.” It has been decimated since the early 1990s due to the use of diclofenac to treat cattles. Consuming the carrion of such cattle has proved lethal for the vultures. In addition, many of our bird species are threatened by the destruction of their habitat due to population pressure.
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