The Florida sandhill crane is just one species an environmental group says the U.S. Fish and Wildlife Service has failed to protect under the Endangered Species Act.

The group is threatening to sue the federal agency.
The Center for Biological Diversity says the U.S. Fish and Wildlife Service determined that more than 400 plants and animals may deserve protection under the Endangered Species Act. But the group says the federal agency never issued final decisions, leaving some species in limbo for up to seven years.

The Center for Biological Diversity issued a 60-day notice of its intent to sue.

The group points to a recent study that found it can take up to 12 years to list a plant or animal under the Endangered Species Act. The federal law requires the process take two years.

The U.S. Fish and Wildlife Service did not immediately return a call seeking comment.