Photographer Brian Moore, 70, caught the mallard ducklings on camera with their mother after they hatched in the village of Hazelbury Bryan on Saturday.
The duck was sitting on 21 eggs, all of which were successfully hatched. Mr Moore said on Saturday he hoped the birds would not be killed by predators.
But an RSPB spokeswoman confirmed the ducklings died on Sunday night. It is thought they might have been eaten.
Their home was a duck house on a lake in the garden of Mr Moore's son.
Before news of the ducklings' demise emerged, Mr Moore described the birds as a "miracle" and said: "I've never seen 21 ducklings before.
"There are a lots of buzzards around here, foxes and crows, and we are hoping they don't get taken by predators."
