听力中关于蜂鸟的一点资料

雅惠乖乖 · 发表于 2005-3-14 10:14:00

蜂鸟，鸟纲，蜂鸟科各种类的通称。体型变化很大，大的象燕子，小的比黄蜂还小，但多数较小。蜂鸟的羽色通常极其艳丽。嘴细长呈管状，舌能自由伸缩。常飞行于花间，取食花蜜和花上的小昆虫，有助传粉。在树枝上营巢。每窝产卵两板。育雏时，雌鸟亲自以长嘴置花蜜于雏鸟食管内。
全世界蜂鸟约有６００种。主要分布于南美和中美；沿美洲西岸往北直达阿拉斯加南部。
蜂鸟在鸟类中已算是很小的了，古巴产的吸蜜蜂鸟，更小，体重不超过２．８克，最小的只有２克，也就是说，４００－５００只古巴吸蜜蜂鸟，总计才有１公斤重。
蜂鸟的体温惊人的高，鸟类专家测定的结果是，平均体温高达４０℃，人类如这种体温恐怕要挂瓶了。蜂鸟不但体温高，更妙的是其温差大，４０℃体温的蜂鸟，在它呈蛰伏状态时，体温则降到１９℃，其中上下相差达２１℃，实在罕见。
蜂鸟的体温高，心跳也快，快得无法使人相信。一只动作敏捷的蜂鸟，每分钟的心跳达到１２６０次，这不但在鸟类，就是在动物界也应该是冠军了。蜂鸟的飞行不但敏捷，而且可以随时快速地作上下左右改变方向的飞行；并且在吸吮花蜜时还可像直升飞机那样，作悬空停顿的动作。所以在美洲它被誉为“空中杂技演员”。
蜂鸟的幼鸟极其安静，母鸟外出觅食，它们会静静地在巢中等待，绝不乱绷乱叫。鸟类专家认为，这种习性是长期适应环境的结果。蜂鸟体小，又无攻击器官与本领，只能靠安静来避免敌害，以求生存。

redpassion · 发表于 2005-3-14 10:44:00

支持~~~

其实JJ背景比JJ本身重要

谢谢你咯

beautywawa · 发表于 2005-3-14 10:51:00

謝謝分享唷！

抱抱日落 · 发表于 2005-3-14 11:17:00

Hummingbirds can fly right, left, up, down, backwards, even upside down. While other birds get their flight power from the downstroke only, hummingbirds have strength on the up-stroke, as well.

A hummingbird's wing is flexible at the shoulder, but inflexible at the wrist.

When hovering, hummingbirds hold their bodies upright and flap their wings horizontally in a shallow figure-8. As the wings swing back they tilt flat for a moment before the wings are drawn

Most hummingbirds flap their wings about 50 or so times a second. This means all we can see is a blur. The Magnificent Hummingbird is an exception; sometimes it flaps it wings slow enough for individual wing beats to be perceived.

The tiny feet of hummingbirds are almost useless except for perching; if hummers want to travel two inches, they must fly. Hummingbirds lift from perches without pushing off; they rise entirely on their own power, flapping their wings at almost full speed before lifting off. Though they fly very fast, they can suddenly stop and make a soft landing. They are so light they do not build up much momentum.

2. FEEDING

Hummers have a fast breathing rate, a fast heartbeat, and a high body temperature. They must feed every 10 minutes or so all day, and they may consume 2/3 of their body weight in a single day.A major part of a hummingbird's diet is sugar. They get it from flower nectar and tree sap. Hummers also need protein in order to build muscles, so they eat insects and pollen. The tongue of a hummingbird has grooves on the side, which are used to catch insects in the air--also from leaves and spider webs.

melodybb1224 · 发表于 2005-3-14 12:39:00

超级感谢哟~~~~

雅惠乖乖 · 发表于 2005-3-15 01:39:00

抱抱日落是我的好姐姐奥~~~总是支持我的~`还喜欢帮我这个懒懒的MM

听力中关于蜂鸟的一点资料

听力中关于蜂鸟的一点资料

所属分类: TOEFL / IELTS

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