A: Oak seeds are found inside acorns, which are the fruits produced by these great, native trees. Not to gross anyone out, but those aren’t seeds. Those are hundreds of droppings from solitary oak leafminer.
Though the pictured leaf on a red background isn’t an oak leaf, below is a better look at oak leafminer damage on a white oak, which is their preferred oak, though they can infest many other types.
By time this damage with a paned appearance is obvious in oaks in late summer, the good news is that those leaves will soon drop in fall, and the pest is no longer an issue. If infested earlier in the season, a healthy oak will start to put out new leaves, despite many branches bearing damage from oak leafminer. No chemicals are necessary.