It was calculated that when its population reached its highest point, there were more than 3 billion passenger pigeons—a number equal to 24 to 40 percent of the total bird population in the United States, making it perhaps the most abundant bird in the world. Even as late as 1870 when their numbers had already become smaller, a flock believed to be 1 mile wide and 320 miles (about 515 kilometers) long was seen near Cincinnati.
Sadly, the abundance of passenger pigeons may have been their undoing. Where the birds were most abundant, people believed there was an ever lasting supply and killed them by the thousands. Commercial hunters attracted them to small clearings with grain, wait until pigeons had settled to feed, then threw large nets over them, taking hundreds at a time. The birds were shipped to large cities and sold in restaurants.
By the closing decades of the 19th century, the hardwood forests where passenger pigeons nested had been damaged by Americans' need for wood, which scattered(驱散)the flocks and forced the birds to go farther north, where cold temperatures and spring storms contributed to their decline. Soon the great flocks were gone, never to be seen again.
In 1897, the state of Michigan passed a law prohibiting the killing of passenger pigeons, but by then, no sizable flocks had been seen in the state for 10 years. The last confirmed wild pigeon in the United States was shot by a boy in Pike County, Ohio, in 1900. For a time, a few birds survived under human care. The last of them, known affectionately as Martha, died at the Cincinnati Zoological Garden on September 1,1914.
【2016高考英语一轮全程复习构想课时训练1(外研版)】相关文章:
★ 【浙江专用】2014届高考英语一轮复习课时作业(三十七)选修8Unit 2《Cloning》
★ 2017届高考英语二轮复习书面表达限时测验:5(含解析)
★ 湖南省岳阳市2014高考英语一轮单项选择训练题(14)及答案
★ 2014高考英语(新人教版)一轮基础训练(12)A、B卷(附答案或解析)
★ 【北师大版】2014届高考英语一轮复习指导课时作业:Unit 11 A卷 Word版含解析
★ (全国通用)2014届高考英语一轮单元复习 限时强化训练十
★ 【北京专用】2014届高考英语一轮复习方案课时作业:选修8 Unit 3 Inventors and inventions
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21