Dr Jolyon Troscianko, from the University of Exeter, and Dr Christian Rutz, from the University of St Andrews, have captured first video recordings documenting how these tropical corvids fashion these particularly complex tools in the wild.

The pair developed tiny video ‘spy-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.

The findings are reported in the Royal Society’s journal Biology Letters on Wednesday, December 23.

[…]”In one scene, a crow drops its tool, and then recovers it from the ground shortly afterwards, suggesting they value their tools and don’t simply discard them after a single use.” According to Rutz, this observation agrees with recent aviary experiments conducted by his group: “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.”

New Caledonian crows (Corvus moneduloides) are found on the South Pacific island of New Caledonia.

They can use their bills to whittle twigs and leaves into bug-grabbing implements; some believe their tool-use is so advanced that it rivals that of some primates.

A Goffin’s cockatoo called ‘Figaro’, that has been reared in captivity and lives near Vienna, used his powerful beak to cut long splinters out of wooden beams in its aviary, or twigs out of a branch, to reach and rake in objects out of its reach. Researchers from the Universities of Oxford and Vienna filmed Figaro making and using these tools.

How the bird discovered how to make and use tools is unclear but shows how much we still don’t understand about the evolution of innovative behaviour and intelligence.

A report of the research is published this week in Current Biology…

The discovery, made by scientists from Oxford University, the University of Vienna, and the Max Planck Institute at Seewiesen, is thought to be the first controlled experimental evidence for the social transmission of tool use in any bird species.

Goffin’s cockatoo (Cacatua goffini) is a curious species of Indonesian parrot not known to use tools in the wild. At a laboratory in Austria the researchers had observed a captive adult male Goffin’s cockatoo named ‘Figaro’ spontaneously start to sculpt stick tools out of wooden aviary beams to use them for raking in nuts out of his reach. To investigate if such individual invention could be passed on to other cockatoos the team used Figaro as a ‘role model’, exposing other birds to tool use demonstrations, some with Figaro as ‘teacher’ and others without his ‘students’ seeing him at work.

In the experiments one cockatoo group was allowed to observe Figaro skilfully employing a ready-made stick tool, while another could see what researchers called ‘ghost demonstrations’ — either seeing the tools displacing the nuts by themselves, while being controlled by magnets hidden under a table, or seeing the nuts moving towards Figaro without his intervention, again using magnets to displace the food. The birds were all then placed in front of an identical problem, with a ready-made tool lying on the ground nearby.

Three males and three females that saw Figaro’s complete demonstration interacted much more with potential tools and other components of the problem than those seeing ghost demos. They picked up sticks more than the ghost demo control groups and generally seemed more interested in achieving the result. Remarkably, all three males in this group acquired proficient tool use, while neither the females in the same group nor males and females in the ghost demo groups did.

A report of the research is published in the journal Proceedings of the Royal Society B.