I Popped down to the river yesterday, for a couple of hours.
After replenishing the feeding station with ten normal sized minnows, the male was soon fishing from it.
It was emptied within 30 minutes, taking 9 to the nest and eating the tenth.
I restocked again with normal size minnows, and once more it was emptied in next to no time.
The chicks should be almost fully grown so they will be fledging very soon.