Well, today was the day, and I got to watch! The first baby out was already on a branch about a foot from the nest when I got there:
I watched it practice flying to another nearby branch: no problem. But it hadn’t given much thought about how to land, and spent a few comical seconds madly hovering before it figured out it needed to be ABOVE the branch before settling down. It continued to practice flying and landing while its sibling stretched its wings. Then mom came along and fed the still-sedentary hummer:
A fun morning!