Posted this morning on DNN chat board by mod GABear:
Some sad news this morning. From what we are seeing right now, it appears that our grackle young have perished. There hasn't been any movement this morning when food was brought.
There are so many possibilities. Fail rate on songbird nests (just in my boxes and such) is pretty high. Parasites, fungal diseases, etc.
The parents lack of brooding for 2 nights when temps there were in the 40's didn't seem normal either.
A couple days ago, the parents were picking at something in the nest bowl really often. Looked like it was consumed (not fecal sacs, something too small to see). I wondered about some insects in the nest then. I never saw black fly visible on cam, but I suppose that's possible too, given that we are seeing the adult eagles being bothered by them.
Just speculation. We'll never know. Many songbirds are able to nest more than once in a season. Hopefully this pair can try again somewhere else.