評論
打印
Recording 70
錄音70
You will hear a lecture about a species of bird called New Caledonian crow.
你將聽到一段課程，講的是一種稱為“新喀里多尼亞烏鴉”的鳥。
First, you have some time to look at questions 31 to 40.
首先，你有些時間看看第三十一題至第四十題。
Now listen carefully and answer questions 31 to 40.
現在仔細聽錄音，回答第三十一題至第四十題。
I'm going to talk today about research into a particular species of bird, the New Caledonian crow, whose natural habitat is small islands in the Pacific Ocean.
今天我將講講關于一種鳥的研究，這種鳥叫新喀里多尼亞烏鴉，其自然棲息地是咋太平洋的一些小島上。
And it seems that these crows are exceptionally resourceful.
從研究結果來看，這些烏鴉特別善于隨機應變。
Using sticks or other tools to find food isn't unknown among birds and animals.
用小棍子或其它工具來覓食在鳥類或其它動物中也不罕見。
Some chimpanzees, for example, are known to bang nuts on stones in order to break the shell and get at the edible kernel inside.
譬如，人們知道，一些黑猩猩會用石頭砸堅果來砸破果殼以取出里面可食用的果仁。
One New Caledonian crow, called Betty, bent some straight wire into a hook and used it to lift a small bucket of her favorite food from a vertical pipe.
一只叫貝蒂的新喀里多尼亞烏鴉，把一些直的金屬絲彎成鉤子，并用鉤子將一籃子她最喜歡的食物從筆直的管道里拉上來。
This experiment was the first time she'd been presented with wire, which makes it very impressive.
這次實驗室她第一次碰到金屬絲，給人們留下了深刻印象。
Another crow, called Barney, has demonstrated his skill at using sticks to forage for food.
另一只叫巴尼的烏鴉，證明了自己用小棍子覓食的技能。
In one research project, scientists from New Zealand and Oxford set captive New Caledonian crows a three-stage problem.
在另一個研究項目中，來自新西蘭和牛津的科學家為捕捉到的新喀里多尼亞烏鴉設置了三步難題。
If they wanted to extract food from a hole, the crows first had to pull up a string to get a short stick, then use that short stick to remove a long stick from a toolbox and finally use the long stick to reach the food.
如果烏鴉想從洞里取出食物，它們得首先拉出一根線，得到一根短棒，然后用這根短棒從工具箱中取出一根長棍，最后用長棍夠到食物。
Amazingly, they worked out how to do this successfully.
令人驚訝的是，它們成功弄明白了該怎么做。
Further experiments carried out at Oxford suggest that crows can also use sticks as tools to inspect all sorts of objects, possibly to assess whether or not they present a danger.
在牛津人們進行了進一步實驗，證明了烏鴉還能將小棍當作工具來試探其它事物，可能是評估它們有沒有危險。
The idea for the experiment came from observing the birds using tools to pick at random objects, such as a picture of a spider that was printed on some cloth.
實驗想法源于人們觀察到鳥會用工具來戳弄隨機目標，例如一張印在布上的蜘蛛圖片。
In this research, five pairs of crows, including Barney, underwent tests to see how they would react to a variety of objects, which were carefully chosen so the birds wouldn't be tempted to view them as a possible source of food.
在此研究匯總，人們給五組烏鴉（包括巴尼在內）做了一些測試來看它們對不同的對象會有什么反應。這些對象都是經過精心挑選的，所以鳥兒們不會將其視為可能的食物來源。
As a further precaution, all the crows had been fed beforehand.
所有的烏鴉都已事先喂過食，作為進一步的防護措施。
On eight occasions, a bird's first contact was by using a tool.
在八個場景中，烏鴉用工具進行初步接觸。
In all three trials, Barney began by using a stick for inspection.
全部三次測試中，巴尼都用小棍子作事先試探。
One involved a rubber snake.
其中一個對象是橡膠制成的蛇。
First he approached it, but didn't touch it, then retreated to pick up a stick.
巴尼首先靠近了蛇，但沒有碰到它，接著撤回去叼起小棍子。
He then prodded it with the stick.
接著巴尼用小棍子戳了一下橡膠蛇。
After some more investigation, he discarded the stick and carried on pecking at the snake more confidently, apparently convinced that it wouldn't move.
經過一些查探后，巴尼把小棍子扔到一邊，更有自信地啄那條橡皮蛇——很顯然，巴尼相信蛇不會動。
In other experiments, two different birds, called Pierre and Corbeau, also made a first approach with tools on three separate occasions.
在其它實驗中，兩只不同的鳥，皮埃爾和科布，也在三個獨立場景中也都用了工具進行初次接觸。
Pierre used a short piece of wood chip to touch a light which was flashing, and Corbeau was seen prodding a metal toad with a stick.
皮埃爾用了一小段木片來觸碰一盞閃爍的燈，科布則用一根小棍戳一只金屬蟾蜍。
Significantly, the crows tended to use the sticks only to make their first contact with the object.
很重要的是，烏鴉傾向于僅在初次與對象接觸中使用小棍子。
Subsequently, they either ignored the object or dropped the tool and pecked at the object, which is very different from using the tool to get access to food.
隨后，烏鴉要不就無視了該對象，要不就把工具丟到一邊，然后用喙猛啄該對象，這和用工具覓食有很大不同。
So what conclusions can be drawn from the research?
從這項研究中，能得出什么結論呢？
Evidence is building up from experiments such as these that the birds are able to plan their actions in advance, which is very interesting for understanding their cognition.
這些及其類似的實驗都提供證據表明，鳥類有能力提前計劃自己的行動，這對于理解鳥類認知能力來說非常有趣。
They don't seem to be responding in a pre-programmed sort of way.
鳥類的反應似乎不是預先設定好的。
It may even be possible that they're able to view a problem and work out what the answer is.
更可能的情況是，鳥類有能力觀察問題，然后想出解決方法。
However, a major difficulty is assessing whether this tool-using behavior is a sign of intelligence.
不論如何，主要的難題在于評估這種使用工具的行為是否智力的體現。
To some extent, this is related to the ecological circumstances in which the animal is found.
某種程度而言，這和動物所處的生態環境也有關系。
So scientists want to find out much more about how the crows behave in their native habitat, and a team from Exeter and Oxford universities is carrying out research in New Caledonia.
所以科學家希望了解更多烏鴉在天然棲息地（環境下）的表現，來自埃克塞特大學和牛津大學的研究隊伍在新喀里多尼亞進行了一些調研。
They're looking into whether the birds' way of searching for food gives them any possible evolutionary advantage.
他們探究的是鳥類的覓食方式能否作為它們的進化優勢。
The birds are hard to observe, as they live in a region of mountainous forest, so the researchers have attached tiny cameras to the tails of some birds, as one method of investigating their behavior.
要觀察到這些鳥類實在很困難，因為烏鴉們生活在山區森林中，所以研究人員得在一些鳥的尾部安裝上微型照相機來調查它們的行為。
The birds are masters at using sticks to find their food, in particular beetle larvae from the trees.
這些烏鴉非常精通于用小棍子覓食，特別是尋找樹上的甲蟲幼蟲。
It's possible that the birds can derive so much energy from these grubs that they only need to eat a few each day.
可能的情況是，烏鴉能從這些食物（甲蟲幼蟲）中吸收到大量能量，所以它們一天只需要吃幾只甲蟲即可。
This would mean that they wouldn't have to spend most of their waking time searching for food, as most animals do.
這意味著，它們不需要花費大量的時間來覓食，大部分動物則需要這么做。
The beetle larvae have a distinct chemical make-up, which can be traced through the feathers and blood of birds that eat them.
甲蟲幼蟲的化學成分非常特殊。以此為食的鳥，其羽毛和血液中都能追蹤到甲蟲的特征。
Scientists have collected samples from crows in order to estimate the proportion of larvae in their diet.
科學家從烏鴉上收集到了一些樣本，以估計甲蟲幼蟲在其食物中所占比例。
They should then be able to gauge the extent to which individual birds depend on using sticks to feed themselves.
然后科學家應該就能估計出一只鳥在多大程度上依賴使用小棍子來喂飽自己了。
We've learnt a great deal about the ability of New Caledonian crows to use tools, and some very interesting research is being carried out into them.
從新喀里多尼亞烏鴉使用工具的能力中，我們學到了許多知識，而且在此領域，人們還做了一些很有趣的研究。
