Scientists have known about crows’ intelligence for years, but a team of biologists from the University of Exeter have made a stunning discovery. According to a report from the Washington Post, scientists attached tiny cameras to New Caledonian crows to reveal that they were actively building tools to help them find food.

The footage reveals the birds using sticks with a hook at the end to get hard-to-reach food. The New Caledonian birds are the first animal other than humans that have figured out how to use hooked tools.

The study was published this week in the journal Biology Letters, and describes the methods used by the researchers that led to the discovery. Scientists set up baited feeding sites and placed the raw tools next to the food, and were shocked when the crows picked up on how to reach the treat by using the hook provided. The crows have still never been filmed exhibiting this behavior in a completely wild setting.

According to the study, the birds are known for their clever use of tools, but are also extremely shy and difficult to study in the wild. The study’s head author, Jolyon Troscianko from the University of Exeter, reveals that the birds are highly sensitive to disturbances, and their habitats are difficult to reach.

Small cameras were attached to the tails of 19 wild New Caledonian crows. Only four of the birds were filmed using the tools, but the footage reveals just how extensive their understanding of tools were. The birds were observed placing the tools down and picking them back up, suggesting that the object has value to the crows.

According to co-author Christian Rutz from the University of St. Andrews in Scotland, “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.”

A press release from the University of Exeter describing the details of the study can be found here.