To build its nest, a bird won’t go for any old twig. Somehow, birds pick and choose material that will create a cozy, sturdy nest.
“That’s just totally mystifying to me,” says physicist Hunter King of the University of Akron in Ohio. Birds seem to have a sense for how the properties of an individual stick will translate to the characteristics of the nest. That relationship “is something we don’t know the first thing about predicting,” King says.