The red maple I mentioned previously has now started flowering. Red maples are usually one of the first trees to start blooming. I recently read Bernd Heinrich's Winter World, which discussed the early blooming of red maples and other trees in the context of bee survival. Early flowers like these provide an advantage to those bee colonies that can afford to sacrifice some scouts to cold snaps in order to find those flowers as soon as they bloom. I did not notice any bees on these flowers, but they were well above my head, so I may have missed some.
Here is a closer look at flowers on a different red maple.
Crocus sprouts are starting to appear as well. Yesterday was the first day I noticed them, but some probably started before then.