your clue. I'd offer it once or twice a day. a drop or two.

The hummer I rescued was almost dead, and I put a drop of sugar water on my finger and held it to her beak and her little tongue came out and slurped it up. (I had to hold her in my cupped hands for about 1/2 hour until she stopped panting.)

Little things die of fright. We have pygmy shrews up North, and they drop dead when the cats chase them. Hummers are in that tiny category too... so it was hit and miss with Sweetums, when my cat brought her in the house! She had no damage, just the sprained wing which she held in a limp way.

There might be enough moisture in the moist dog food. If this little bird is still alive and responsive, that is a good sign.
Crows are mean, and raid nests, and throw baby birds out.
We've seen them do that up North. A bunch them get together like a gang and go thru the trees and cackle up a storm and throw them out. This might have happened to Maxie. Jays will do it too.