An Australian animal rights group endorsed a continuing cull of 400 kangaroos on the outskirts of the country's capital, saying that it was a humane way of dealing with overpopulation.
Authorities began the controversial killing outside Canberra on Monday after a proposal to relocate them to remote forest land proved too costly. Activists have been gathering at the site and some have threatened to disrupt the cull.
About 600 kangaroos live at the abandoned military site, and scientists say their growing population threatens their own survival as well as that of other native species.
Michael Linke, of the Royal Society for the Prevention of Cruelty to Animals, said his organization was monitoring the cull and inspectors at the site Monday found that animal welfare standards were met.
The animals were being rounded up into pens, tranquilized and given a lethal injection.
"A lot of people have been saying that the kangaroos have been a little bit stressed and there's some concern about the tranquilizing phase," Linke told Australian Broadcasting Corp. radio. But he said the relocation alternative would have also caused tremendous stress.
"I don't think there is any best way to manage this," Linke said. "It's the only option" for the Defense Ministry. The cull is expected to take about three weeks. The issue has split Australians over the merits of killing their national symbol to protect rare lizards and insects that share their grassy habitat.
While there are organizations dedicated to rescuing and rehabilitating injured kangaroos, many people see the fast-breeding animal as a pest that eats crops and pasture intended for livestock and is a hazard to motorists.
The government estimated there are between 15 to 50 million kangaroos across the country depending on seasonal conditions. The four most abundant species of kangaroo can be harvested under a government license, and the meat is exported around the world.