Haveyoueverwonderedwhybirdssing?Maybeyouthoughtthattheywerejusthappy.Afterallyouprobablysingorwhistle(吹口哨)whenyouarehappy.Doyouknowwhata“territory”is?Aterritoryisanareathatana

题目详情

Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all you probably sing or whistle (吹口哨) when you are happy.

Do you know what a “territory” is? A territory is an area that an animal usually the male claims （声称）as its own. Only he and his family are welcome there. No other families of the same species (物种) are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you you might shout. Probably this would be enough to frighten him away.

　　　　 If so you have actually scared the stranger away without having to fight him. A bird does the same thing. But he expects no outsiders almost any time especially at nesting （筑巢）season. So he is screaming all the time whether he can see an outsider or not. This screaming is what we call a bird’s song and it is usually enough to keep an outsider away.

Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

You can see that birds have a language of their own. Most of it has to do with attracting mates and setting up territories.

56. Some scientists believe that most of the time birds’ singing is actually 　　　 .

A. an expression of happiness　　　　　　　　　　　　　 B. a way of warning

　　　 C. an expression of anger　　　　　　　　　　　　　　　 D. a way of greeting

57. What is a bird’s “territory”?

　　　 A. A place where families of other species are accepted.

　　　 B. A place where a bird may shout at the top of its voice.

　　　 C. An area for which birds fight against each other.

　　　 D. An area which a bird considers to be its own.

58. Why do birds keep on singing at nesting season?

　　　 A. Because they want to invite more friends.