With all the acorns on the oak trees and the branches being so low you can get a good look at them and one of the things that you get to see amongst the bumper crop is Acorn Galls.

Acorn galls are abnormal growths on acorns and their cups, caused by gall wasps laying their eggs in the developing acorns. These galls are essentially plant tissue that the tree produces in response to the wasp’s eggs and secretions. The galls can vary in shape, size, and color, depending on the specific wasp species and the oak species involved. 

While they may affect the appearance of the acorns, they are generally not harmful to the tree’s overall health.

So if you are out and about and you pass an oak tree have a look at the acorns and see if you can spot any acorn galls.