Goffin’s cockatoos have been added to the short list of non-human animals that use and transport toolsets. In a study publishing in the journal Current Biology on February 10, researchers show that the cockatoos carry multiple tools to their worksite when the job calls for it. This behavior has only been previously reported in chimpanzees, our closest relatives.
From: Cell Press
February 11, 2023 -- Goffin’s
cockatoos are small white parrots that hail from the Tanimbar Islands
archipelago in Indonesia. Captive Goffin’s cockatoos use and manufacture tools,
and a recent study of wild-caught cockatoos reported that they can
use up to three different tools to extract seeds from a particular fruit. Up
until now, though, it wasn’t clear whether the cockatoos considered these tools
as a “set”; it’s possible that what may look like a toolset is instead nothing
more than a chain of single tool uses, with the need for each new tool
appearing to the animal as the task evolves.
Now, a team of
researchers have used controlled experiments to clarify that the cockatoos do
indeed recognize when a job requires more than one tool. “With this experiment
we can say that, like chimpanzees, Goffin’s cockatoos not only appear to be to
using toolsets, but they know that they are using toolsets,” says first author
Antonio Osuna-Mascaró, an evolutionary biologist at the University of
Veterinary Medicine Vienna. “Their flexibility of behavior is stunning.”
Osuna-Mascaró was
inspired by the termite-fishing Goualougo Triangle chimpanzees of northern
Congo, the only other known non-human animal to use toolsets. These chimpanzees
fish for termites via a two-step process: first, they use a blunt stick to
break holes in the termite mound, and then they insert a long, flexible probe
to “fish” the termites out of the holes. In this study, Osuna-Mascaró’s team
tasked the cockatoos with fishing for cashews instead of termites.
To mimic the
termite-fishing set-up, the researchers presented the cockatoos with a box
containing a cashew behind a transparent paper membrane. To reach the cashew,
the cockatoos had to punch through the membrane and then “fish” the cashew out.
They were provided with a short, pointy stick for punching holes and a
vertically halved plastic straw for fishing.
Seven of the ten
cockatoos tested taught themselves to extract cashews successfully by punching
through the membrane, and two of the cockatoos (Figaro and Fini) completed the
task within 35 seconds on their first attempt. The cockatoos don’t have an
equivalent foraging behavior in the wild, so there was no chance that their
tool use was based on innate behaviors, and each cockatoo used a slightly
different technique.
Next, the team tested
the cockatoos’ ability to change their tool use in a flexible manner depending
on the situation. To do this, they presented each cockatoo with two different
types of box: one with a membrane and one without. The cockatoos were given the
same two tools, but they only needed the pointy stick when a membrane was in
the way. “The cockatoos had to act according to the problem; sometimes the
toolset was needed, and sometimes only one tool was enough,” says
Osuna-Mascaró.
All of the cockatoos
mastered the test in a very short period of time and were able to recognize
when a single tool was sufficient. However, the birds engaged in an interesting
behavior during this choosing phase. “When making the choice between which tool
to use first, they were picking one up, releasing it, then picking up the other
one, releasing it, returning to the first one, and so on,” says Osuna-Mascaró.
The researchers found that when cockatoos did this switching, they performed
better on the tests.
Next, the team tested
the cockatoos’ ability to transport the tools as a set on an as-needed basis.
They put the cockatoos through a series of increasingly challenging trials to
reach the boxes: first they had to climb a short ladder while carrying their
tools; then they had to fly horizontally with them; and in the final test, they
had to carry the tools while flying vertically. As before, the birds were only
sometimes presented with a box with a membrane barrier, so they had to decide
whether the problem required one or both tools.
Some cockatoos learned
to carry the two tools together—by inserting the short punching stick into the
groove of the halved straw—when they were presented with a box that required
both. This meant they only had to make one trip, albeit while carrying a
heavier toolset. Most of the cockatoos transported the toolset on an as-needed
basis, further indicating that they knew ahead of time when two tools were
required, though some made two trips when necessary. One cockatoo, Figaro,
decided not to waste time thinking and instead carried both tools in almost
every trial.
“We really did not know
whether the cockatoos would transport two objects together,” says Alice
Auersperg, senior author on the study and a cognitive biologist at the
University of Veterinary Medicine Vienna. “It was a little bit of a gamble
because I have seen birds combining objects playfully, but they very rarely
transport more than one object together in their normal behavior.”
There’s a lot more to
be learned about cockatoo tool use, the researchers say. “We feel that, in
terms of technical cognition and tool use, parrots have been underestimated and
understudied,” says Auersperg.
“We’ve learned how
dexterous the cockatoos are when using a toolset, and we have a lot of things
to follow-up on,” says Osuna-Mascaro. “The switching behavior is very interesting to
us, and we are definitely going to use it to explore their decision making and
their metacognition—their ability to recognize their own knowledge.”
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