Sorry for the unsteady (and unedited) video--I don't do video much, and I'm still working it out.
The Ruby-Throated Hummingbird is still on her nest near Oak Bridge. There were singing Robins all over the Ramble.
At Turtle Pond, which last year was a very active nesting area, there seems to be very little activity. The biggest drop-off is the Red-Winged Blackbirds--there were at least six nests last year, belonging to four males. This year, I hear a single RWBB in the area, and I'm not entirely sure he has a mate. I think this is because the Conservancy removed the tall phragmities grasses and replace them with slower-growing grasses; I think the blackbirds did not like the lack of cover at the time they were deciding where to nest.
Other missing nesters are more predictable. Downy Woodpecker--I watched a nesting pair all last June--won't re-use a nest hole, and Turtle Pond doesn't have many suitable trees. The Kingbirds I think are nesting on the other side of Belvedere Castle this year. I am surprised that I don't know where any oriole nests are; they're around somewhere, but probably also in the Ramble.
Grackles are nesting in numbers, of course. Just try to stop 'em.
I heard what I believe is that Common Yellowthroat with the odd pizza pizza song. I think of him as Little Caesar.