Crows and their close relatives ravens are known to be quite intelligent, with scientific experiments showing how they can hitch rides on bald eagles and remember the faces of captors. New research has now uncovered a previously unknown ability, with crows being observed building tools from multiple parts for the first time ever.

There are scientists who believe corvids, the family that includes crows, ravens, rooks and jays, may be among the most intelligent animals on Earth due to their memories, problem-solving skills and ability to anticipate future events. But while it has been known for years that crows have the ability to use tools, combining multiple elements to create them is something that until now has only been observed in humans and great apes.

In what is described as an astonishing mental feat, scientists at the University of Oxford and Max Planck Institute for Ornithology have watched on as New Caledonian crows assembled implements from smaller component parts.

The work involved an experiment where eight New Caledonian crows were presented with a puzzle box they had never seen before. Inside the box was a small food container behind a door with a slender gap along the bottom. Sticks long enough to pull the food towards the opening were scattered nearby, with every single one of the birds able to use the tools to retrieve their snacks without too much trouble.

The scientists then dialed up the difficulty by replacing those lengthy sticks with shorter components, each too tiny to reach the food on their own. But with some of the sticks hollowed out and others able to slot into the ends, with a little know-how these components could easily be pieced together to form the required tool.

With no assistance at all, four of the eight crows were able to assemble one small piece into another to build a composite tool of the length required to reach the food. The scientists took things even further, replacing the components with even smaller pieces, with one enterprising crow by the name of Mango able to combine three and even four components to get the job done.

"The results corroborate that these crows possess highly flexible abilities that allow them to solve novel problems rapidly, but do not show how they do it," says Alex Kacelnik, from the University of Oxford's Department of Zoology. "It is possible that they use some form of virtual simulation of the problem, as if different potential actions were played in their brains until they figure out a viable solution, and then do it."

The discovery is significant, because some anthropologists consider compound tool-making to have been a critical step in the evolution of the human brain. This is largely because it involves some premeditated idea about the superior capabilities of the finished product, an as yet unseen object.

While this newfound ability doesn't necessarily suggest that crows share the same cognitive abilities as humans or apes, it does shed further light on the mechanisms that drive problem-solving. The teams says these kinds of processes could provide a basis for artificially intelligent robots that can come up with creative solutions to problems they haven't encountered before.

You can see these clever crows do their thing in the video below, while the research was published in the journal Scientific Reports.