United States definitions:

Endangered species means any species which is in danger of extinction throughout all or a significant portion of its range other than a species of the Class Insecta determined by the Secretary to constitute a pest whose protection under the provisions of this Act would present an overwhelming and overriding risk to man. There are six infraspecific taxa that are presumably extinct that are members of listed endangered species that are not extinct.

Threatened species means any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.

Candidate species are those plant and animal species for which the Fish and Wildlife Service has sufficient information on their biological status and threats to propose them as endangered or threatened under the Endangered Species Act.

Proposed Candidate are species for which the Fish and Wildlife Service has proposed as endangered under the Endangered Species Act. Proposals are published in the Federal Register.

No Status include taxa that have not been through the formal federal process. This also includes species that warrant candidate status but have not been processed.

The listing of a species under the Endangered Species Act is a legal process based on biological properties carried out by the U.S. Fish and Wildlife Service. It is not a biological assessment. In order to list, reclassify, or delist a species, the Service must follow a strict legal process known as a "rulemaking" (regulatory) procedure. The rule is first proposed in the Federal Register, a U.S. government publication. After a public comment period, the Service decides if the rule should be approved, revised, or withdrawn. The process takes up to a year, or longer in unusual circumstances, and encourages the participation of all interested parties, including the general public, the scientific community, other government agencies, and foreign governments.

Once an animal or plant is listed, all protective measures authorized by the Act apply to the species and its habitat. Such measures include protection from any adverse effects of Federal activities; restrictions on taking, transporting, or selling a species; authorization for the Service to develop and carry out recovery plans; the authority to purchase important habitat; and Federal aid to State and Commonwealth wildlife agencies that have cooperative agreements with the Service.

The Service has developed a priority system designed to direct its efforts toward the plants and animals in greatest need of protection. The magnitude of threat is the most important consideration, followed by the immediacy of the threat and the taxonomic distinctiveness of the species (the most distinctive is a monotypic genus, then a full species, and lastly a subspecies, variety, or vertebrate population).

This report by the Fish and Wildlife Service shows the species listed in Hawaii based on published historic range and population. Additional information can be found on the USFWS Pacific Region site as well.