It sounds like a House Wren got them to me. You've done everything right, but those HOWR are very sneaky and usually destroy all the eggs in a matter of seconds. The egg may still be viable if it doesn't have a hole pecked in it. I would leave it for now. The Chickadees are such sweet birds, and not very good at defending their nests. If all the eggs were destroyed, the Chickadees will probably abandon that nest.

I haven't seen any HOWR around, but it could be. I thought if they evicted a nest, they would build one with their sticks in it. Maybe not.

Oh, that is so sad. The baffle should have prevented some other predator such as a raccoon or squirrel from reaching into the nest

I agree with Kendra. Probably a HOWR. Too bad for the little Chickadees. If you had that much nest disruption, I would bet that they will totally abandon the nest. When you are sure that they have abandoned, just go ahead and clean out the box. Maybe you will get another nesting pair there.~~Angie

If it were a HOWR, I would think it would have built its nest in the box. I thought that was their MO. Anyway,the chickadees are still checking the box. I doubt if there's a baby, since they don't stick around for long. Maybe it is another pair looking for a nest?

I'll keep you posted.

Sometimes the HOWR just evict, throw in a stick or two & go to the next box or cavity. If you haven't seen them have you heard them? Even though I really dislike the HOWR tactics, they are only doing what comes naturally to them & I love their bubbly song. This year out of 4 houses I had sucessful nestings of Carolina chickadees, Tree Swallows, Blue Birds and now the House Wrens are feeding young. The Dees & Trees both arrive way before the wrens so the young have a better chance.
Susan

Usually I do have HOSPS and HOWRS in my yard. I closed up the bluebird house, since I could only trap so many HOSPS before it became too much. I have not seen or heard any HOWR this year, but they could still be around.

I saw the chick leave yesterday afteroon, and I peeked inside. Now there were 2 eggs (instead of 1), covered with down. The other old egg was still jammed between the wall and nest.

I've read info that says they usually don't renest in the same place after predator attack. But it's either them or another pair nesting in the old nest.

Should I remove that old egg on the side?

This is exciting and mysterious at the same time.