At around 30 cm long, the oak jay is the smallest of Europe's corvids, and also the most colorful. It skillfully reproduces the sounds of birds, mammals such as cats, and fire sirens, to intimidate potential predators. In autumn, it builds up its winter reserves by hiding large quantities of oak acorns and beech faines under moss or leaf litter. To find its hiding place, it memorizes landmarks and may also place small pebbles next to its hiding place to act as beacons. Forgotten seeds germinate in spring. In this way, the oak jay contributes to tree reproduction and forest regeneration.