结构分析
第一分句：Much is said about the flying speed of the peregrine falcon 是被动语态.
1.主语 much 是不定代词,从分隔在后的定语 about the flying speed of the peregrine falcon可以推断出 much 指代的是“有关游隼的飞行速度的事情”
2.本句可以改写为主动语态：People say much about the flying speed of the peregrine falcon
第二分句：and many claims have been made,ranging from 125mph to more than double that 是带有分词短语充当状语的被动语态.
1.主语 many claims have been made = people have made many claims (有人已经多次断言)；
2.分词短语 ranging from 125mph to more than double that 起补充说明作用,意思是“从125英里/小时到大于两倍的这一速度之间变动”.其中 that 指代 flying speed.
翻译：人们已经提到过有关游隼的飞行速度的大量事情,而且还多次做出断言,它们的飞行速度间于125英里/小时到两倍以上之间.