Which of these birds is one of the main sources of movement and propagation for the oak tree?

The Eurasian jay ('Garrulus glandarius') is a species of bird occurring over a vast region from Western Europe and north-west Africa to the Indian Subcontinent and further to the eastern seaboard of Asia and down into south-east Asia. Across its vast range, several very distinct racial forms have evolved to look very different from each other, especially when forms at the extremes of its range are compared.

The bird is called jay, without any epithets, by English speakers in Great Britain and Ireland. It is the original 'jay' after which all others are named.

Before humans began planting the trees commercially on a wide scale, Eurasian jays were the main source of movement and propagation for the European oak, each bird having the ability to spread more than a thousand acorns each year. Eurasian jays will also bury the acorns of other oak species, and have been cited by the National Trust as a major propagator of the largest population of Holm oak.