New Caledonian Crows And The Use Of Tools - IELTS Listening Answers & Explanations
From Official Cambridge Guide to IELTS Academic Listening Test 8 · Part 4 · Questions 31–40
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Questions 31–40 Note Completion
Complete the notes below.
Write ONE WORD ONLY for each answer.
New Caledonian crows and the use of tools
Examples of animals using tools
- some chimpanzees use stones to break nuts
- Betty (New Caledonian crow) made a 31 out of wire to move a bucket of food
- Barney (New Caledonian crow) used sticks to find food
New Zealand and Oxford experiment
- three stages: crows needed to move a 32 in order to reach a short stick; then use the short stick to reach a long stick; then use the long stick to reach food
Oxford research
- crows used sticks to investigate whether there was any 33 from an object
- research was inspired by seeing crows using tools on a piece of cloth to investigate a spider design
- Barney used a stick to investigate a snake made of 34
- Pierre used a stick to investigate a 35
- Corbeau used a stick to investigate a metal toad
- the crows only used sticks for the first contact
Conclusions of above research
- ability to plan provides interesting evidence of the birds' cognition
- unclear whether this is evidence of the birds' 36
Exeter and Oxford research in New Caledonia
- scientists have attached very small cameras to birds' 37
- food in the form of beetle larvae provides plenty of 38 for the birds
- larvae's specific 39 composition can be identified in birds that feed on them
- scientists will analyse what the birds include in their 40
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q31 | hook | One New Caledonian crow, called Betty, bent some straight wire into a hook and used it to lift a small bucket of her favourite food from a vertical pipe | Excerpt/Transcript Explanation: The transcript explains that the crow, Betty, reshaped a straight wire into a hook shape to help her pull up a container of food. Answer Explanation: The answer is hook, which is a piece of metal or material that is curved at one end and used for catching or holding things. Reason For Correctness: The correct answer is hook because the transcript describes an experiment where a crow named Betty changed the shape of a straight piece of wire. She bent it into a 'hook' so she could use it to pull up a food bucket. |
| Q32 | string | In one research project, scientists from New Zealand and Oxford set captive New Caledonian crows a three-stage problem: 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 | Excerpt/Transcript Explanation: The transcript describes a test with three parts. To get a short stick used for the next part of the test, the birds first had to pull on a piece of string. Answer Explanation: The answer is a long, thin piece of material that the birds had to pull to get a tool. Reason For Correctness: The correct answer is 'string' because the text describes an experiment with three steps. In the first step, the crows had to move or "pull up" a string so they could get a short stick. This short stick was then needed for the next steps to eventually get food. |
| Q33 | danger | 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 | Excerpt/Transcript Explanation: The transcript says that new experiments at Oxford show that crows use sticks to look closely at many different things to see if those things might be dangerous. Answer Explanation: The answer means a situation or an object that could hurt or harm someone or something. Reason For Correctness: The correct answer is 'danger' because the transcript explains that researchers at Oxford studied how crows use sticks to look at many different things. They did this to find out if the birds were trying to see if those things might hurt them. The text uses the word 'inspect', which means the same thing as 'investigate' used in the notes. |
| Q34 | rubber | One involved a rubber snake. First he approached it, but didn't touch it, then retreated to pick up a stick | Excerpt/Transcript Explanation: The transcript explains that in one of the tests, Barney the crow looked at a fake snake made of rubber. Instead of touching it with his body first, he went to get a stick to poke it. Answer Explanation: The answer "rubber" is the type of material that the fake snake was made from in the experiment. Reason For Correctness: The correct answer is extracted from the section of the transcript describing Barney's participation in an experiment. To test how crows react to unknown objects, researchers used several items. The text specifically mentions that one of these trials involved a "rubber snake" which Barney approached and then touched with a stick to see if it was safe. |
| Q35 | light | Pierre used a short piece of woodchip to touch a light which was flashing | Excerpt/Transcript Explanation: The transcript says that a crow named Pierre used a small bit of wood to touch a light that was turning on and off. Answer Explanation: The answer means a small lamp or an object that shines and gives off brightness. Reason For Correctness: The correct answer is 'light' because the text explains that Pierre used a piece of wood (called a woodchip) to touch a flashing light as his first way of looking at it. In the context of the experiment, touching something with a tool to see what it is can be described as investigating. |
| Q36 | intelligence | However, a major difficulty is assessing whether this tool-using behaviour is a sign of intelligence | Excerpt/Transcript Explanation: The transcript explains that it is hard for scientists to decide if using tools really shows that the birds are smart. Answer Explanation: The answer means the power to learn, think, and understand well. Reason For Correctness: The correct answer is taken from a part of the talk where the speaker discusses what the experiments prove. The notes say it is 'unclear' if the birds' behavior is 'evidence' of something. In the transcript, the speaker says there is a 'difficulty is assessing' (which means it is unclear) if using tools is a 'sign' (which means evidence) of intelligence. |
| Q37 | tails / tail | 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 behaviour | Excerpt/Transcript Explanation: The transcript explains that it is difficult to see the crows in the wild, so scientists put small cameras on the birds' tails to help them study what the birds do. Answer Explanation: The answer is the part of the bird's body at its back end where the scientists put the cameras. Reason For Correctness: The correct answer is tail(s) because the text says that researchers put small cameras on that specific part of the birds. This was done because the birds live in forests where it is very hard for people to see them and watch their behavior. |
| Q38 | energy | It's possible that the birds can derive so much energy from these grubs that they only need to eat a few each day | Excerpt/Transcript Explanation: The transcript says that because these insects give the birds a lot of energy, the birds only have to eat a small amount of them every day. Answer Explanation: The answer means the power or fuel that birds get from food to stay alive and active. Reason For Correctness: The correct answer is derived from the part of the transcript discussing the diet of the New Caledonian crows. The text explains that the beetle larvae (also called grubs) provide a high amount of energy. Because these larvae are so nutritious, the birds do not need to eat many of them to get the strength they need for the day. Key terms to notice are 'derive' (meaning to get or obtain) and 'grubs' (a synonym used for the beetle larvae). |
| Q39 | chemical | The beetle larvae have a distinct chemical make-up, which can be traced through the feathers and blood of birds that eat them | Excerpt/Transcript Explanation: The transcript explains that the beetle larvae have a special chemical structure. Because of this, scientists are able to find signs of that structure in the birds that eat the larvae. Answer Explanation: The answer "chemical" refers to the specific substances or matter that the beetle larvae are made of. Reason For Correctness: The correct answer is supported by the transcript's mention of the beetle larvae having a "distinct chemical make-up." In this context, "make-up" is a synonym for "composition." Scientists can trace or identify this unique chemical signature in the feathers and blood of the crows to understand what they have been eating. |
| Q40 | diet | Scientists have collected samples from crows in order to estimate the proportion of larvae in their diet | Excerpt/Transcript Explanation: The transcript says that researchers have taken samples from the birds to figure out how much of their daily food consists of beetle larvae. Answer Explanation: The answer is 'diet', which means the kind of food that a person or animal eats every day. Reason For Correctness: The correct answer is chosen because the transcript explains that scientists are studying what the crows eat. By taking samples from the birds' feathers and blood, the researchers can see how many beetle larvae (a type of insect) are in their 'diet'. This matches the note about scientists analyzing what the birds include in their food intake. |
Transcript
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. And it seems that these crows are exceptionally resourceful.
Using sticks or other tools to find food isn't unknown among birds and animals. Some chimpanzees, for example, are known to bang nuts on stones, in order to break the shell and get at the edible kernel inside. One New Caledonian crow, called Betty, bent some straight wire into a hook and used it to lift a small bucket of her favourite food from a vertical pipe. This experiment was the first time she'd been presented with wire, which makes it very impressive. Another crow, called Barney, has demonstrated his skill at using sticks to forage for food.
In one research project, scientists from New Zealand and Oxford set captive New Caledonian crows a three-stage problem: 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. Amazingly, they worked out how to do this successfully.
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. 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. 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. As a further precaution, all the crows had been fed beforehand.
On eight occasions, a bird's first contact was by using a tool. In all three trials, Barney began by using a stick for inspection. One involved a rubber snake. First he approached it, but didn't touch it, then retreated to pick up a stick. He then prodded it with the stick. After some more investigation, he discarded the stick and carried on pecking at the snake more confidently - apparently convinced that it wouldn't move.
In other experiments, two different birds, called Pierre and Corbeau, also made a first approach with tools on three separate occasions. Pierre used a short piece of woodchip to touch a light which was flashing, and Corbeau was seen prodding a metal toad with a stick.
Significantly, the crows tended to use the sticks only to make their first contact with the object. 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.
So what conclusions can be drawn from the research? 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. They don't seem to be responding in a pre-programmed sort of way: it may even be possible that they're able to view a problem and work out what the answer is. However, a major difficulty is assessing whether this tool-using behaviour is a sign of intelligence. To some extent, this is related to the ecological circumstances in which the animal is found.
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. They're looking into whether the birds' way of searching for food gives them any possible evolutionary advantage. 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 behaviour.
The birds are masters at using sticks to find their food, in particular beetle larvae from the trees. It's possible that the birds can derive so much energy from these grubs that they only need to eat a few each day. This would mean that they wouldn't have to spend most of their waking time searching for food, as most animals do.
The beetle larvae have a distinct chemical make-up, which can be traced through the feathers and blood of birds that eat them. Scientists have collected samples from crows in order to estimate the proportion of larvae in their diet. They should then be able to gauge the extent to which individual birds depend on using sticks to feed themselves.
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.