Clever New Caledonian crows can use three tools

New Caledonian crows have given scientists yet another display of their tool-using prowess.

Scientists from New Zealand's University of Auckland have found that the birds are able to use three tools in succession to reach some food.

The crows, which use tools in the wild, have also shown other problem-solving behaviour, but this find suggests they are more innovative than was thought.

The University of Auckland team set seven wild crows a complicated problem.

The birds were presented with some out-of-reach food; a long tool, which could be used to extract the food, but which was also out of reach, tucked behind the bars of a box; and a short tool, which could be used to extract the long tool, but which was attached to the end of a dangling piece of string tied to the crow's perch.

The team were surprised to see that the birds were able to solve the problem, as this video of Sam the New Caledonian crow reveals.

Footage courtesy of Auckland University