Black bird nest!

hi!

about a week ago we noticed a lovely black birds nest right outside my sons window with 5 beautiful eggs! so we decided to set up the nesting camera... we waited for mother to leave to set it up and when she came back all was fine   I turn it off at night as it’s to dark to see... unfortunately this morning we’ve woken to only 4 eggs and I can’t see the egg on the floor! I’m thinking it was pinched by a predator .. but why did they only take the one? And now my heart is sinking at the thought of the others being snapped up one by one I will leave all alone and no interfere, after all it is natures way! But just wondered why only one was missing? Thank you!