Blackbird Nest - 4th brood attempt - Day 10

Checked first thing this morning and found that one of the two chicks and the egg had gone :( I assume it was not a rat since the nest I would have expected to be empty. Not sure whether it was a magpie (which were around early morning). Through the rest of the day feeding continued and I would have expected the Magpie to be back when the parents were both away from the nest ..... so not sure what happened. Hoping this one survives until it fledges. Just been a mare of a season for this female.
[UPDATE] Got home to find the 2nd chick dead on the ground near the nest. Shame, must have fallen out. I even wonder if I had checked early morning when I got up if it would have been alive and could have been put back in the nest. At least it wasn't a predator.