Chipmunks and squirrels will eat baby birds, could be one of them took it from the nest, then perhaps something startled them, so they scooted off and left the baby bird. I've had robins build nests under my deck every year, seldom do the eggs hatch and grow up. Usually, all of a sudden, the eggs are just gone. Sometimes, the eggs do hatch but the baby birds disappear too. I do have a lot of chipmunks and squirrels (also a large black snake!) so any of them could be the culprit. Harsh, but that's nature. Now I have a wren with babies in my hanging flower basket, which is hanging from a shepherd's hook. Its actually a good place for them, I don't believe anything can climb up the metal hook. I do have to be very careful when watering the basket, but I don't mind. She's just a mother raising her babies, I am happy to do whatever I can to help.

I just came out to water my tomatoes this morning, and there was another dead baby robin ON my deck! This one had not been there very long- it was not dried out but was clearly not breathing or moving. It's been very hot over the last week, so I'm wondering if perhaps they die in the nest and the mother moves them away. It's very sad to see this! I haven't had lots of luck with nature - a duck hatched 12 ducklings in my azaleas, then took them to the pond nearby,but she was back about 3 weeks later laying a new clutch. After sitting on them only about 2 days, a fox scared her off and took the eggs....I saw it on my security camera.

It seems to me you've had great luck with nature, since you have multiple species choosing your yard to nest in. They just aren't choosing safe locations, based on the predators in your neighborhood. I am sorry you have to witness the death. Hopefully, there will be some successes, as well.

Don't be discouraged. These things happen and they make us sad but hopefully you'll witness something wonderful in your yard. I've seen enough dead robin babies myself but eventually they nest again and the others survive.