Fascinating research shows that rooks, members of the corvid family like crows, can use tools to enhance their access to food. In this case, they used stones to raise water level in a tube high enough so they could get a worm out of the tube. The video demonstrates Connelly the rook's ingenuity; later experiments (also available on YouTube) show Cook the rook putting stones in tube of water rather than sand to get his worm.
Cell Press describes their featured video: "Corvid birds are known for their intelligent use of tools. In this video, three different rooks (Connelly, Cook, and Monroe) use stones to raise the water level in a vial in order to reach a floating worm, as described in detail in the paper by Bird and Emery published online on August 6. In the first two trials, Connelly is required to raise the water level by a varying amount by using seven stones and one stone, respectively. In the third trial, Monroe uses preferentially larger stones to get to the goal, and in the last trial Cook drops the stones into a vial with water as opposed to one containing sawdust."
A related note: I love that Cell Press is marketing its authors' research / publication with a YouTube video channel. It's a great way to promote science!
For More Information
- Bird, Christopher David, and Nathan John Emery Rooks Use Stones to Raise the Water Level to Reach a Floating Worm. Current Biology, August 6 2009.