听力文本

If you've ever been to an all-you-can-eat buffet, you know how important it is to carefully weigh your options.
You don't want to fill up on salad when so many calorie-laden delights await.
It seems some birds also weigh their mealtime choices—literally.
A study finds that Mexican Jays pick up and shake peanuts to assess their relative heft before choosing one.
That report is served up in the Journal of Ornithology.
Foods that hide their edible bits on the inside present a challenge to hungry diners.
How can you tell which fruits are ripe or which shells harbor the biggest nuts?
We humans knock on melons or squeeze avocados.
But how do other species select the highest quality snacks?
To find out how the jays do it, researchers fiddled with their feed.
First they doctored peanuts so that some contained three nuts while others had none.
When they offered these pods to some jays, the birds turned their beaks up at the empty shells and instead chose those that were full.
And when the jays were allowed to choose between normal peanuts and those that weighed just one gram more,because the researchers had stuffed them with clay, the birds again went for the heavier meal.
Videos revealed that the jays shake the nuts before selecting one,
which apparently lets them gauge the nut's mass and perhaps also listen for the rattle of a well-packed shell.
Pretty clever for a bird brain.

参考译文

如果你去过任君吃到饱的自助餐，你就会明白仔细慎重食物的重要性)jXs4sO%;Aavr。
在面前摆满满是高卡路里的美食时，你肚子里肯定不想全是沙拉WxyT&Dbbpw。
而从字面意思上讲一些鸟类也会这样选择自己的食物t)XQ)MSWGEi9VdI3sT。
一项研究发现墨西哥松鸦在挑选坚果时会通过摇晃对其重量进行评估#*wXp!pZs3rw]d。
这项研究已经在《鸟类杂志》上发表0&juwhnw^CRzM@fqt=U%。

某些食物的可食用部分是在其内部，因此对这些饿货们而言无疑是个难题[wxCsfV-Y9plW。
你该如何分辨果实的成熟或哪个是最大的坚果呢?
我们人类通常会通过在西瓜上拍拍或在牛油果上挤挤的方式挑选hLBHYHm4b|EC)0fGrt。
但其它物种又是怎样选择呢?
为探究墨西哥松鸦的行为方式，研究人员在它们的食物中做了手脚^Ow8;OQMxp.4syIU~h。
他们先下手的是坚果，使得一些坚果中有3粒果肉，另一些则一个也没有oY,-JfDxPsir]^^。
当这些坚果呈现在墨西哥松鸦面前时，它们用嘴去碰触那些空壳，然后选择了满满果肉的gYgA=)(_h8。
而后这些墨西哥松鸦面对的是正常及重一克的坚果，松鸦再一次选择了较重的坚果，因为研究人员在一些坚果涂上粘土使其比正常版本重一克_q4-R2PE6I+X。
视频显示墨西哥松鸦在选择时会先进行摇晃.fP.bVu^,+AJz&kyp.。
这样的动作能够判断坚果的重量，甚至倾听食物内部的声音K]-xWGQcgd~NxU0Pw。
对鸟类而言这已经算是顶尖聪明了q=Zs=oA*adV4b[WaJ。

译文为可可英语翻译，未经授权请勿转载！

重点讲解

1.fill up 填补；装满

例句:I fill up the tank with gasoline about once a week.
大约每个星期我加满一箱汽油eLXrCppGC~hg&~5T。

2.pick up 捡起；拾起

例句:The economy remains deep in recession with few signs of a pick-up.
经济仍深陷衰退之中，几乎没有好转的迹象[nL)dcVV%RY@]JVpO]。

3.find out 发现；查明；找出

例句:Find out how much your surveyor's and solicitor's fees will be.
弄清你要向鉴定员和律师支付多少费用m1Wl!+Mi-[#9C。

4.allow to 允许

例句:Add a little of the warmed milk and allow to froth a little.
加一点温牛奶，并让它起点儿沫B1_E%vcQQ6Ji8LeUcoo。