Susan Healy

than small ones, and that the method doesn’t work when the tube contains sawdust instead of water. Together with Bird and her student Lucy Cheke, Clayton transferred the Aesopian experiment to jays, demonstrating that the ability to use tools is a wider phenomenon in the corvid family, and not restricted to the Corvus genus. Confronting the jays with a range of variations of the experiment, the researchers also tried to establish what goes through the birds’ minds. The model that best predicts their behaviour states that they tend to do whatever achieves the movement of food towards the point where they can reach it, and that their action is to some extent influenced on causal connections, but not reliant on it. Clayton’s group has also demonstrated that corvids can plan for the future in ways that were thought to be unique to humans (Nature (2007), 445, 919–921). In their most recent publication, Cheke and Clayton show that Eurasian jays can distinguish two separate future needs and plan for them accordingly, even if it conflicts with present motivations (Biol. Lett. online November 2, 2011, doi: 10.1098/rsbl.2011.0909). From her work with apes and children, Clayton can appreciate how clever the jays and other corvids are. “Children typically reach this level at the age of seven,” she says. Surely that’s worth dancing about.