As the first corellas flock into the Murraylands and begin roosting for the summer, local councils are still unsure what to do about them.
The Murray Bridge council and others are waiting on advice from the University of South Australia and Department of Environment, Water and Natural Resources, who have been researching the best way to manage the destructive native birds.
The researchers' report was due in July but is still unfinished.
The council has written to the university to express its disappointment and ask for a draft copy of the report.
A range of corella control options will be put before councillors when it arrives.
The researchers are expected to offer advice about which control methods have been found to be most effective and socially acceptable, what can be done at individual sites in the short term, and how to discourage the species in the long term.
Other councils have tried bird-scaring pistols, patrols by fixed-wing aircraft, culling of "scout" birds, ultrasonic noises, mass trapping and euthanasia by gas, strobe lights and even a falcon to try and control corellas in the past few years.
But the Murray Bridge council’s Malcolm Downie said it was clear there was no simple answer.
"Culling can be quite unpopular with some residents and with tourists, who often don't understand the damage the birds to to infrastructure," he said in a report to the council's last meeting.
"There is no short-term solution that won't involve intense public debate and discussion, and because little corellas are mobile, any solution will, at best, only move the problem to another part of the rural city."
He said the research project might offer some understanding about why corella numbers had grown in recent years and what could be done to ease them back down over time.
Rural landowners are entitled to shoot corellas, but firearms may not be used in townships.
Destruction of the birds by any other means requires a permit and compliance with animal cruelty standards.