Canberra's annual kangaroo cull begins on Wednesday night, with 1606 eastern grey kangaroos in shooters' sights, 450 more than last year.
But Territory and Municipal Services Minister Shane Rattenbury has softened the news for cull protesters, announcing that one site will be set aside for a trial of fertility control for up to 500 kangaroos. Fertility control had never before been done on that scale for kangaroos, he said.
Eight reserves will be closed from Wednesday night, with two shooters contracted by the government to do the cull.
The nature reserves are the Callum Brae off Mugga Lane, Goorooyarroo and adjacent land in Gungahlin, Jerrabomberra Grassland West, Kama near Hawker, Mount Painter near Cook, Mulanggari in Gungahlin, Mulligans Flat in Gungahlin, and the Pinnacle and adjacent land near Hawker.
Mount Painter and the Pinnacle will be closed from 5pm till 7am each night; the other sites will close from 3pm till 7am.
The government says the cull is done now to avoid the time when females have large joeys. Most joeys at this time are small and unfurred. Last year, 355 "pouch young" were killed - by a blow to the head, not shooting - in addition to the 1149 culled.
Mr Rattenbury said the government had a responsibility to protect the reserves by managing kangaroo populations and minimising the impact of heavy grazing on other native animals and plants.
The trial of fertility control will be done at the Gungaderra Nature Reserve in Gungahlin, chosen because it is relatively land-locked by major roads, including Gungahlin Drive and the Barton Highway, so the effectiveness of the trial can be gauged.
The government is working through the details with animal rights group Alphadog, which has proposed tranquilising the kangaroos and administering a fertility drug called Deslorelin.
Alphadog director Marcus Fillinger met Mr Rattenbury last week, and put to him a cost of $255 per kangaroo, which covers the drugs only.
Mr Fillinger reacted angrily to news of the cull, announced on the eve of the budget.
He said Mr Rattenbury had made no mention of the looming cull at last week's meeting, and had promised to let him know when it would be announced.
"Mr Rattenbury assured me with a handshake that we would be informed before a cull was announced, and I can't even get hold of him," Mr Fillinger said on Monday night.
"Here is a man we're supposed to be trusting and yet I've put in five months of my charity's resources to provide him a get-out-of-jail-free card and I'm the last to know."
Describing the government as determined to "kill a bucketload of animals", Mr Fillinger said he had not even been told that his charity would do the fertility control trial.
Mr Fillinger said his fertility offer was cheaper than shooting, which had cost $340 a kangaroo last year.
But Mr Rattenbury said he had emailed Mr Fillinger and tried to contact him by phone on Monday night. He had told Mr Fillinger he would like to work with him on the trial.
"The ACT will be a leading jurisdiction if this project works, so this is significant move by the government to explore non-lethal alternatives to culling."
This year's is the biggest cull since 2011 when 2439 were killed.
The government insisted the cull was necessary, with very favourable conditions for eastern grey kangaroos and increasing numbers.
Some Canberra nature reserves had among the highest densities of kangaroos per square kilometre in Australia. Overgrazing destroyed precious ecosystems and threatened the survival of other plants and animals, including the grasslands earless dragon, the striped legless lizard, the perunga grasshopper, the hooded robin, the brown treecreeper, the superb parrot, and the white-winged triller.
The government said it was not cost-effective to sell the kangaroo meat, given the relatively low numbers and the high costs of running a commercial operation, but it said 10 per cent of the meat would be made into baits for wild dogs and foxes.
Director of Parks and Conservation Daniel Iglesias said the cull numbers were based on scientific counts in each location and the sustainable carrying capacity for each area.