Crows make expert shape spotters

Carrion crows (Corvus corone) can add geometry to their already impressive list of mathematical skills. Researchers showed sets of six shapes to two crows and tasked them with spotting the odd one out. The birds aced simple tests, picking a crescent moon from a group of stars with little trouble. Even on more difficult tasks — picking out one slightly distorted quadrilateral from a group of otherwise very similar regular shapes — the crows still performed well, even when the shapes were randomly rotated and scaled.