Lawyers for the wildlife service said they could not do that.
Last year, 41 were killed by the wildlife service in Wyoming.
A spokesman for the wildlife service said it had never received such a proposal.
David Olsen, an assistant director of the wildlife service, said a review was under way to see whether the management system should be changed.
The wildlife service said one to three acres of marsh disappear each year.
The wildlife service has been caught in the middle, along with 250 species awaiting consideration for protection.
The wildlife service will be soliciting public comments on the release before making a final decision.
A good deal of money should become available now that the Wildlife Service controls its own budget.
Though 15 camp scouts have been trained by the wildlife service, they remain idle, he said.
Parks and Wildlife Service, includes only the base set above.