Eurasian jays perform many functions which benefit the ecosystems they inhabit. Their alarm calls alert other species, including red squirrels (Sciurus vulgaris), to the presence of predators. They consume carrion, removing potential disease sources and helping in making nutrients available in the ecosystem.
One of their most important ecosystem roles is the dispersal of acorns from Quercus trees. Eurasian jays eat most of the acorns they take, but they also bury acorns and forget about them, leading to oak regeneration. Eurasian jay prefer collecting and burying viable acorns over infertile, dead, or damaged acorns, making them excellent dispersal agents. They preferentially store acorns on the edges of clear spaces, which is the best place for seedlings to get the right amount of light for germination. Oak trees, including Quercus robur and Quercus petrea, are keystone species in their habitats, providing homes and food for many species of animals, plants, fungi, and lichen. About 80% of all insects on the IUCN Red List need oak trees as part of their life cycle.
Ecosystem Impact: disperses seeds; creates habitat; biodegradation