I think it is a witch hazel, hamamelis.

I think I've solved the mystery! I think it's a warbling vireo. I don't think they've been to our property before....but who knows for sure. They are very secretive. Our 35 acres has exploded with growth this year. I think it's because of the severe winter we had, followed by an incredibly wet spring. So much fun getting a new bird around here! Last year, I started hearing a northern parula, and I'm still hearing it. I've googled the warbling vireo's nest and some of the images look just like mine. Woohoo!!

Ummm... dunno what species tqh11890's critter is, but it looks to me like a caterpillar that has formed a cocoon. THIS (above) photo is a tomato hornworm that has been parasitized by a species of tiny Braconid wasp. I often see these on my plants. Leave them because they devour the cats from within and so the "worms" no longer are eating, but instead ensuring another generation of parasitic wasps. The white rice-like objects are the cocoons of the wasp larvae that finished eating & exited the skin of the caterpillar to complete their metamorphosis.

Sad update. I noticed three babies in the nest at first. Then there seemed to be only two and today there are none. I looked on the ground hoping to find them but I didn't see any. I feel bad because if I hadn't been clearing that area and exposed the nest, they might have been alive today. Maybe I should have relocated the nest. I saw the parents chasing a catbird away. Could that have been the culprit? Or maybe it was five(!) young grey squirrels that have recently come out of a tree not too far away? So sad!