I think the squirrels have become satiated with all the walnuts and buckeye nuts falling on the ground this past week. Here is what they left behind as I tried to clean up their messy harvest.
I raked up an entire mixing bowl full of buckeye nuts left behind by the squirrels at the base of the tree. A few of the nuts had a bite or two out of them, but most were unscathed. They are so heavy and slick, they slide right into any crevice in the lawn and get more or less buried there — ready to germinate next Spring and create a little Buckeye forest.
Meanwhile the squirrels look like this…
“I’m so full — I can’t eat another thing, not even a wafer thin mint”.
A la Monty Python’s sketch in “The Meaning of Life”
The strategy of satiating predators with an over-abundance of food ensures that some of the seed crop (or animal prey in the case of carnivores) remains unharmed, able to carry on the next generation. Who said trees weren’t smart?
Back Yard Biology 
I wish a few of those gorgeous squirrels could make my place their home!
I would love to send you some — the backyard is overrun with them. Of course, I contribute to their presence by having so much birdseed available.
I thought thought they were horse chestnuts, Aesculus hippocastanum. The nuts look very similar. Amelia
You’re right. Amelia. Buckeye is in the Horse Chestnut family. I wonder if the nuts of your Horse Chestnut are any more palatable than our buckeye nuts.
We use the horse chestnuts as children to play a game called “conkers” as they are inedible but at the moment we are spoiled here by the lovely edible chestnuts we can find in the woods. We like ours roasted. Amelia