Manufacture and use of hook-tools by New Caledonian crows

  title={Manufacture and use of hook-tools by New Caledonian crows},
  author={Gavin R. Hunt},
  • G. Hunt
  • Published 18 January 1996
  • Biology
  • Nature
TOOL behaviour in wild birds has been described as mostly stereotyped1,2, and tool manufacture involves little modification of material3–5. Here I report in New Caledonian crows Corvus moneduloides the manufacture and use of two different types of hook tool to aid prey capture: hooked-twig and stepped-cut barbed pandanus leaf. Crow tool manufacture had three features new to tool use in free-living nonhumans: a high degree of standardization, distinctly discrete tool types with definite… 
Hook tool manufacture in New Caledonian crows: behavioural variation and the influence of raw materials
It is shown that New Caledonian crows’ manufacture of hooked stick tools can be much more variable than previously thought, and can involve two newly-discovered behaviours: ‘pulling’ for detaching stems and bending of the tool shaft.
The crafting of hook tools by wild New Caledonian crows
  • G. Hunt, R. Gray
  • Biology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2004
To make all 10 tools, the crows carried out a relatively invariant three–step sequence of complex manipulations that involved (i) the selection of raw material, (ii) trimming and (iii) a lengthy sculpting of the hook.
Species-wide manufacture of stick-type tools by New Caledonian Crows
15 additional stick-type tools collected from New Caledonian Crows since the first detailed description of these tools in 1996 are described, indicating that stick- type tools are used widely by Crows and that they are used throughout the year.
Direct observations of pandanus-tool manufacture and use by a New Caledonian crow (Corvus moneduloides)
Direct observations of a crow making and using stepped pandanus tools at Pic Ningua verify most of the claims based on the artefact record, but the crow’s exact manufacture technique was slightly different to that inferred previously.
A novel tool-use mode in animals: New Caledonian crows insert tools to transport objects
Six observations, in two individuals, of a novel tool-use mode not previously reported in non-human animals, where one subject used a stick to transport an object that was too large to be handled by beak, which suggests the tool facilitated object control.
New Caledonian crows keep ‘valuable’ hooked tools safer than basic non-hooked tools
This study is the first to use safekeeping behaviour as a proxy for assessing how non-human animals value different tool types, establishing a novel paradigm for productive cross-taxonomic comparisons.
Selection of tool diameter by New Caledonian crows Corvus moneduloides
New Caledonian crows handling of tool diameter is examined, showing that when facing three loose sticks that were usable as tools, they preferred the thinnest one, and that they manufacture a tool of a suitable diameter from a tree branch according to the diameter of the hole through which the tool will be inserted.
New Caledonian crows show behavioural flexibility when manufacturing their tools
New Caledonian crows have demonstrated flexible behaviour when using tools and solving novel problems. However, we do not know whether this flexibility extends to tool manufacture. Here, we show that
The development of pandanus tool manufacture in wild New Caledonian crows
The results show that theDevelopment of wide pandanus tool manufacture is a lengthy process comparable to the development of tool use in primates, and exposure to parental tools might help juveniles form a mental template of functional tool design and facilitate the faithful transmission of local design traditions.


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