NOOOOOooooooo!!!

Totally devastated, went out to feed the birds and found the robins nest on the ground :(
They have been such good parents and I could hear the chicks every time mum or dad flew into the ivy. What happened?? Do you think a cat or fox? Also read squirrels can raid nests :(
Heart broken, they must have been so close to fledging.... Mum was still hanging around too.