To amend the Endangered Species Act of 1973 to provide that artificially propagated animals shall be treated the same under that Act as naturally propagated animals, and for other purposes.

HR 520 amends the Endangered Species Act to eliminate distinctions between animals bred naturally in the wild and those bred artificially in captivity. The bill requires the Secretary of the Interior to treat both types of animals identically for all decisions under the Act, including listing and critical habitat designations. It also specifically authorizes using artificially propagated animals as part of mitigation for projects affecting endangered or threatened species. This applies to all species covered by the Act, regardless of when they were listed.