A duck flock looks well defended — all that water, all those eyes — and loses birds anyway, because a duck's habits work against it in ways a hen's do not. Ducks dabble head-down for long stretches with their attention in the mud, they are slow and reluctant to leave the water when alarmed, and on land they waddle where a hen runs. A hawk that has taken one duck from a pond will return to the same water, because the flock's behaviour there is predictable. Protection therefore concentrates on the water and its banks: make the approach dive difficult, give the flock somewhere to scramble to, and change the hours at which they are out unwatched.
Cover the water, not just the land
Hens escape under a bush; ducks escape onto the pond — which is exactly where a stooping hawk wants them if the water is open. Break up that clean approach by stretching netting over the pond or, on a large pond, over the shallow corner the flock actually uses, supported on posts so the ducks swim freely beneath it. Where netting is impractical, criss-crossed lines of fishing line or cord strung between bank posts above the water interfere with a dive in the same way and are nearly invisible to us. Plant the banks: overhanging shrubs, reed clumps and a low shelter at the water's edge give a duck that does come ashore somewhere to be under within two strides, and deep enough water in the middle of the pond lets the flock dive — a submerged duck is a failed hunt.
Feeding and housing that keep ducks out of the open
A feed station on open grass pins the whole flock, heads down, in the one place a hawk would choose. Feed beside the bank shelter or under the netted section, scatter some feed into the shallows, and site the duck house close to the water with its pop-hole facing cover, so the morning exit and the evening return are short covered dashes. Keep the area around the house clear of the ambush perches a hawk uses to wait — a dead tree or isolated post overlooking the pond is a hunting seat; the same bird forced to hunt on the wing, without a lookout, finds the flock far harder to surprise.
The hours, and the losses that should change your setup
Raptors learn a yard's timetable, and duck losses typically bunch at first light, when the flock is let out hungry onto open ground, and in the last hour before housing. Delay the morning release a little during a spell of attacks and bring the housing time forward, and supervise those windows in person for a few days: a human standing at the pond is the one deterrent no hawk argues with. Treat any loss as information — where on the water or bank it happened tells you which approach line is uncovered, and the fix belongs there, not spread thinly over the whole holding. One or two losses in a season to a passing migrant is the cost of free-ranging; a bird a week is a covered-pond problem asking to be built.
Put the risky hours on a named rota
Supervision only protects ducks if it actually happens on the wet mornings and the evenings you are late home. Name who lets the ducks out, who is pond-side for the last hour, and who houses them, and let the rota travel with the flock's records rather than living in memory. On KinsLe, Care Teams sets those dawn release and dusk housing jobs as assigned duties with a named person on each, so during a run of hawk attacks the covered hours are claimed and completed — and timestamped proof replaces the hopeful belief that someone must have been down there.