Dr Gavin Hunt and Dr Russell Gray of the University of Auckland have spent the past decade studying feathered technology in New Caledonia, 900 miles north-east of Australia. After an intensive field survey of local crow industry, the scientists found that the birds rip the leaves of the pandanus tree to fashion three distinct types of tool for grub and insect extraction: wide, narrow and tapered.
Long ago, the birds discovered that they could rip the serrated edge off the leaves to make a wide tool. The skill spread and the crows honed tools with finer working tips, by either narrowing tools or tapering them. (Because the leaves are reinforced by tough parallel fibres, the tapered design is made in steps. The crow nips the leaf, rips along the fibres, makes another cut and tears again, repeating until it has a tool with usually two, three or four steps.)
Leaf tool manufacture is an example of culture: the birds leam through example and their tool-making wisdom grows in sophistication down the generations. The crows appear to have the cognitive requirements for cumulative, though rudimentary, technological evolution, said Dr Gray. Tool manufacture in New Caledonian crows shows striking flexibility and innovation.’ The ability of the birds to innovate is further shown by their making of other tools. They often strip a twig of leaves and cut it off just below a shortened offshoot to create a hook to get bugs out. They also use simpler tools to extract grubs from the dead wood of trees.
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Question Focus: The diagram sentence describes what the birds do to the leaves first - it needs a verb showing the action.
Correct Answer: D
Why this is correct: The diagram says something like the birds ___ the leaves. In the passage, we are told the birds rip the leaves of the pandanus tree to make tools. The verb that matches this action is rips.
Passage Reference: the scientists found that the birds rip the leaves of the pandanus tree to fashion three distinct types of tool for grub and insect extraction: wide, narrow and tapered.
Common Mistake: Some students choose narrowing because it also describes a process. But narrowing happens later when improving tools, not the first action. This is a wrong section trap.
Paraphrasing: Passage: 'rip the leaves' = Diagram: '___ the leaves'
Tips: For verbs in diagrams, look for the exact action word in the passage, not a later stage of the process.
Key Vocabulary:
- rip = tear
- fashion = make
Question Focus: The diagram asks what type of tree the leaves come from.
Correct Answer: C
Passage Reference: the scientists found that the birds rip the leaves of the pandanus tree to fashion three distinct types of tool for grub and insect extraction: wide, narrow and tapered.
Why this is correct: The diagram refers to the type of tree. The passage clearly says the birds rip the leaves of the pandanus tree, so the correct label is pandanus.
Common Mistake: Students sometimes choose grub because it is also mentioned nearby. But grub is what they extract, not the tree. This is a context shift trap.
Paraphrasing: Passage: 'pandanus tree' = Diagram: '___ tree'
Tips: When the diagram asks about materials, focus on nouns like tree, leaf, or object - not what the tool is used for.
Key Vocabulary:
- extract = pull out
- tool = instrument
Question Focus: The diagram shows one type of tool made from the leaf and asks for its name.
Correct Answer: G
Passage Reference: the scientists found that the birds rip the leaves of the pandanus tree to fashion three distinct types of tool for grub and insect extraction: wide, narrow and tapered.
Why this is correct: The passage lists three types of tools: wide, narrow and tapered. The diagram position matches the first type mentioned, so the correct label here is wide.
Common Mistake: Some students choose tapered because it sounds more technical. But the diagram follows passage order, and wide is mentioned first. This is a wrong section trap.
Paraphrasing: Passage: 'wide' = Diagram: '___ tool'
Tips: Diagram labels usually follow the same order as the passage - do not jump ahead.
Key Vocabulary:
- distinct = clearly different
- type = kind
Question Focus: The diagram asks for another type of tool shape made by the birds.
Correct Answer: A
Passage Reference: the scientists found that the birds rip the leaves of the pandanus tree to fashion three distinct types of tool for grub and insect extraction: wide, narrow and tapered.
Why this is correct: The final tool type shown in the diagram matches the third type named in the passage. Since the passage lists tapered as one of the three tools, this label fits here.
Common Mistake: Students sometimes choose narrowing because it looks similar. But narrowing is an action, not a tool type. This is a paraphrase trap.
Paraphrasing: Passage: 'tapered' = Diagram: '___ tool'
Tips: Check whether the blank needs a noun or a verb - many wrong answers fail this grammar check.
Key Vocabulary:
- tapered = becoming thinner at one end
- design = shape
General Tips:
- Diagram positions usually follow the same order as the passage - work from top to bottom.
- Always decide if the blank needs a noun, verb, or adjective before choosing from the word bank.
- Cross out each option after you use it so you do not reuse the same word.
- If two options look similar, go back to the exact sentence in the passage and match meaning, not just topic.
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