Rooks Make and Use Tools

Rooks are not observed using tools in the wild, which makes this discovery by Nathan Emery and the appropriately named Christopher Bird (see my chapter Clever Corvids) all the more interesting because they prove to be adept tool users and makers in the laboratory setting. We need an explanation for this "latent" form of cognition. As the BBC article explains, they perform on first trial without intensive learning. They prove able to select an appropriate stone for diameter to push into a tube to release a trap-door and thus the food, and they fashion appropriate hooks from straight pieces of metal to fish for food in a bucket in a perspex well. They have also been seen to make tools involving two steps. This is immensely important because it means that the rooks are not operating under some simple behavioural rule which rewards with instant gratification but can use a tool to make a tool to get the reward - a much more impressive feat. This is called metatool use and was previously thought to be unique to hominins. Rooks have now joined New Caledonian crows as the master tool-makers of the animal world showing, again, that big-brained corvids are a match for chimps in this area at least. You can find he abstract to their paper in PNAS at http://www.pnas.org/content/early/2009/05/28/0901008106.abstract?etoc=