Recent livestock deaths are causing government wildlife groups to remove three Mexican gray wolves from the wild.

The U.S. Fish and Wildlife Service and the Arizona Game and Fish Department are attempting to catch two male and one female wolf using tranquilizer darts shot from helicopters.

The Center for Biological Diversity said it believes removal of those wolves will hinder the already limited genetic diversity of the species.

“Since reintroduction began 15 years ago, Fish and Wildlife...has shot and trapped many genetically valuable wolves, removed them to captivity, and (did) not bred them in any case,” said Michael Robinson, conservation advocate at CBD.

Robinson also said all of the wolves in the wild are descendants of a group of seven wolves that were captured for captive breeding during the time the animal was most in danger of extinction.

Game and Fish did not return requests for comment.

An official release on gray wolves states that released wolves and their offspring are designated as “nonessential experimental population,” and can be removed if they prey on livestock.

The wolves in question are the offspring of released wolves.

The last census of wolves, performed in January, showed 75 wolves in the wild, with three breeding pairs.

Since the reintroduction of the Mexican gray wolf to the wild, government officials have removed 54 from the wild, and that includes 19 accidental killings.