每当白嘴鸦丢下一根香烟或一小块垃圾的时候，人们就会用一个装了鸟食的小盒子来鼓励鸟儿们打扫公园。

The birds will be encouraged to clean the park through the use of a small box that delivers a small amount of bird food each time the rook deposits a cigaret and/or a small piece of rubbish.

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现在，科学家报道说乌鸦亲戚白嘴鸦能用同样的扔石技巧来够到浮动的蠕虫。

Now, scientists report that some relatives of crows called rooks used the same stone-dropping strategy to get at a floating worm.

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So he begins here: Rookslive in a crowd and are mainly vegetarian; Crow may be either another name for rook, especially when seen alone, or it may mean the solitary Carrion crow.

所以他开头这样写道：,白嘴鸦过着群居的生活，它们大部分是素食者;,单独看的时候，乌鸦也能做白嘴鸦的别名，或者乌鸦就是指独居的吃腐肉的乌鸦。

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