London: If you thought only humans or primates can forge and use tools, you are wrong. Crows can make, use, and even store for re-use certain tools while foraging for food, a new study shows.
Scientists have captured video recordings showing how wild New Caledonian crows make and use "hooked stick tools" to hunt for insect prey.
Video recordings by Jolyon Troscianko from the University of Exeter and Christian Rutz from the University of St Andrews document how these tropical corvids fashion these particularly complex tools in the wild.
The pair developed tiny video aspy-cameras' which were attached to the crows, to observe their natural foraging behaviour.
They discovered two instances of hooked stick tool making on the footage they recorded, with one crow spending a minute making the tool, before using it to probe for food in tree crevices and even in leaf litter on the ground.
New Caledonian crows are notoriously difficult to observe, not just because of the challenging terrain of their tropical habitats, but also because they can be quite sensitive to disturbance, according to Troscianko.
"The first time I watched the footage, I didn't see anything particularly interesting. Only when I went through it again frame-by-frame, I discovered this fascinating behaviour. Not once, but twice!" Troscianko said.
The crows use their bills to whittle twigs and leaves into bug-grabbing implements.
In one scene, a crow drops its tool, and then recovers it from the ground shortly afterwards, suggesting they value their tools and do not simply discard them after a single use, the researchers noted.
"Crows really hate losing their tools, and will use all sorts of tricks to keep them safe. We even observed them storing tools temporarily in tree holes, the same way a human would put a treasured pen into a pen holder," Rutz said.
The findings were reported in the Royal Society's journal Biology Letters.