Wild Justice has raised over £32,000 as part of a crowdfund aiming to set up a legal challenge over the government's badger cull.
The group's co-founders TV presenter Chris Packham, author Dr Mark Avery and conservationist Dr Ruth Tingay, launched the appeal.
"We regard it as an unwarranted assault on wildlife which will not eliminate bovine TB from dairy herds," the group's online fundraiser states.
"We contend that Defra and Natural England have failed to define humane practices and that unacceptably high number of badgers, killed by free shooting, die slowly and painfully every year."
It adds: "In 2014 an expert panel advising government on animal welfare standards for culls recommended that 'in the context of controlled shooting of badgers by trained and licensed contractors, the percentage of animals surviving for more than 5 min after being shot, and the percentage being wounded but not retrieved, should not together exceed 5%'.
"Natural England's own annual reports show that this standard is never met in practice and that the number of badgers taking longer than 5 minutes to die or failing to be recovered is consistently about 10% - twice as high as recommended."
Wild Justice says it wants to 'initiate a debate' on the 'inappropriate methods' employed to facilitate the cull and challenge their legality.