The native wood ducks “became territorial” and their defacating in the water had become a public health issue, the council said.

Up to 20 ducks from Helensburgh Pool are to be caught and killed, and another 15 at Corrimal Pool.

Residents have asked why the ducks can’t caught and moved to a suitable habitat elsewhere but council has not responded.

Council said an adult duck was drowned by a staff member at Helensburgh and its ducklings later drowned.

One woman offered that the ducks could be brought to her property to live but council has not responded.

At the pools now, cages are in place and a contractor is trapping the ducks to be taken away and destroyed.

“Unfortunately the ducks are territorial and if relocated, likely to return to the pool surrounds,” a council spokeswoman said.

“We wish there was another way, but despite having tried many other options (over a number of years), we’ve had to gain approval to have the ducks trapped and humanly euthanised by an authorised contractor.”

The Mercury asked if council had ever tried removing the birds to another location, tagging them to see if they returned, but council would not answer this question.

One duck was killed after an unfortunate incident.

“On Saturday 14th October, a number of ducklings entered Helensburgh Pool,” the spokeswoman said. “Some adult ducks became aggressive towards two children in the pool. Council staff were unable to contact Australian Feral Management ... to assist in removing the ducks that were behaving territorially.

“Concerned about public safety, a staff member then attempted to remove the ducklings from the pool.  While doing so, an adult duck reacted aggressively and was accidentally badly injured. The staff member, for humane reasons, made a judgement call to euthanise the duck on site by drowning.”

Three days later the ducklings came back and tried to swim in the pool but drowned on Tuesday evening.