Newborn Ducklings’ First Swim

In the three weeks since I spotted the wild mallard sitting on a nest in our strawberry house (see my posting of 18th April) I’ve checked on her every morning and every evening. She has lain there quietly, motionless, in fact so still that a visitor thought she might be dead. How long would it take for her eggs to hatch? ​

And then, tonight, when I got back from work I found the nest empty. Bewilderingly, there was no sign of any broken shells- could it be that there were no ducklings after all? And then, about two hours later, I spotted the duck in the little pond which serves as an overflow to our Japanese pool. She had twelve adorable little chicks with her. They had made quite a long trek from the kitchen garden and were now having their first swim. Unfortunately I can’t hold out much hope for their future. In previous years the cats and crows have killed them in the first 24 hours. Will this brood survive any longer than the broods of previous years? Or will the cats and crows get them, as before?