What are these things dropping out of my Oak tree?
I have a deck underneath a large, mature oak tree. I've never seen this before but I have these little (1-2mm) balls falling out of my Oak tree on to my deck and lawn furniture. They are quite evenly distributed and numerous so I'm quit sure they are coming out of the tree. The catkins fell a couple weeks ago and I'm used to dealing with them but this is new. I'll attach some pictures.
Ottawa County Michigan
Have no idea what they may be, unless they are undeveloped acorns stressed for whatever reason, possibly ongoing dry weather.
That looks like the frass (excrement) of a moth caterpillar. There are many species that might be feeding on oak at this time of year.