A flock of American flamingos has been slaughtered by a wild fox after bungling zoo keepers forgot to lock them in their enclosure overnight.

Shocked staff at Schoenbrunn Zoo, in Vienna, Austria, found the birds' savaged bloody remains in their open-air section last Monday night, October 16.

Only two of the flock's 15 birds remained alive, reports local media.

Zoo spokesman Johanna Bukovsky admitted: 'Unfortunately, a mistake happened. We forgot to bring the animals into the indoor facility.'

The birds, usually found in tropical or sub-tropical regions, are always brought into their indoor enclosure at night in case of temperature drops.

And not only had keepers forgotten to move the flamingos, but they also forgot to turn on the electric fence that keeps out wild predators.

Bukovsky confessed: 'The problem of foxes in the zoo is well known. We have extensive protective measures.'

The two surviving American flamingos (Phoenicopterus ruber) have been sent to Schmiding Zoo, Upper Austria, to recover.

Meanwhile, one neighbour who lives next to the zoo released video footage of a fox she found trying to eat her children's two pet rabbits.

The fox fled hungry, and some believe it may have been the same one responsible for the flamingo bloodbath.

The neighbour said: 'I saw the fox in my garden trying to get the rabbits in their cage, but it ran off when we opened the door.'

Following the flamingo slaughter, the zoo said it would remind employees of their duty to keep animals safe.

They also said they plan to set live traps to capture wild predators with the help of experts from the Climate, Forestry, and Agriculture Department.

Schoenbrunn Zoo is now only left with a greater flamingo (Phoenicopterus roseus) colony.