Crows keep special tools extra safe
Study suggest that crows have some concept of the relative 'value' of different tool types

Date:
December 21, 2021
Source:
Max-Planck-Gesellschaft
Summary:
Just like humans, New Caledonian crows are particularly careful when
handling their most valuable tools, according to a new study. The
research reveals that crows are more likely to store relatively
complex and efficient foraging tools for future use than more
basic tools.



FULL STORY ==========================================================================
Just like humans, New Caledonian crows are particularly careful
when handling their most valuable tools, according to a new study by researchers from the University of St Andrews and the Max Planck Institute
of Animal Behavior in Konstanz, Germany. The research reveals that crows
are more likely to store relatively complex and efficient foraging tools
for future use than more basic tools.


==========================================================================
New Caledonian crows are renowned for using different types of tools
for extracting prey from tree holes and other hiding places. While they
firmly hold their tools in the bill during foraging, they need to put
them down to eat.

This is when crows are at risk of losing their tools by accidentally
dropping them or having them stolen by other crows.

In an earlier study, the researchers from the School of Biology at the University of St Andrews in the UK had shown that crows keep their tools
safe when not needed, using one of two 'safekeeping' strategies -- they
either securely hold them trapped underfoot, or they temporarily insert
them into a nearby hole or behind bark. But are crows more careful when handling particularly valuable tools? Handle with care "Many of us will
fuss about a brand-new phone, making sure it does not get scratched,
dropped or lost. But we may handle an old phone with a cracked screen
quite carelessly," said lead author Barbara Klump, who is now based at
the Max Planck Institute of Animal Behavior, Germany.

Crows at one of the team's long-term study sites use two different kinds
of stick tools: complex hooked tools and basic non-hooked tools. The
former are painstakingly crafted from a relatively scarce plant species,
while the latter are simply twigs and leaf petioles sourced from the
forest floor. "Hooked tools are not only more costly to obtain, but
they are also much more efficient," explained team leader, Christian
Rutz. "Depending on the foraging task, crows can extract prey with these
tools up to ten times faster than with bog-standard non-hooked tools."
Keeping valuable tools safe In their new study, the researchers now
discovered that New Caledonian crows are more likely to keep valuable
hooked tools safe between uses than the more basic non-hooked tools. "It
was exciting to see that crows are just that bit more careful with tools
that are more efficient and more costly to replace.

This suggests that they have some conception of the relative 'value'
of different tool types," noted study co-author James St Clair.

This is the first study to investigate how animals handle and store tools
of different kinds, providing an innovative way to measure how much they
value these objects. The method has huge potential for investigating the behaviour of other tool-using animals, including our closest relatives,
the chimpanzees.

========================================================================== Story Source: Materials provided by Max-Planck-Gesellschaft. Note:
Content may be edited for style and length.


========================================================================== Related Multimedia:
* New_Caledonian_crow_with_hooked_tool ========================================================================== Journal Reference:
1. Barbara C Klump, James JH St Clair, Christian Rutz. New Caledonian
crows
keep `valuable' hooked tools safer than basic non-hooked
tools. eLife, 2021; 10 DOI: 10.7554/eLife.64829 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211221102752.htm

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