Gobbling up acorns

In the last few weeks it has become apparent that this is an acorns mast year, a bumper year for these seeds - and also for many berries. The evergreen oaks in my local park have not been an exception: Grey Squirrels and Woodpigeons are enjoying this bonanza and feeding on fallen acorns on the ground and the remaining ones in the tree. Today a large flock of Woodpigeons, including many juveniles, feasted on acorns in the park. I managed to record some videos of the feeding activities of the Woodpigeons in the trees and the ground underneath. I find it amazing that the Woodpigeons swallow the acorns whole, presumably their digestive system dissolving the tough shells.
At some point in the sequence, something scared the woodpigeons and most of the flock took to the air. The one I was filming stayed put in the tree, looking up nervously.