U.S. Fish & Wildlife Service

Listing a Species as

Threatened or Endangered

Section 4 of the Endangered Species Act

The Endangered Species Act of 1973 is

one of the most far-reaching wildlife

conservation laws ever enacted by any

nation. Congress, on behalf of the

American people, passed the ESA to

counteract the alarming rate of extinctions

facing many fish, wildlife and plant species.

The purpose of the ESA is to protect

endangered and threatened species and

the ecosystems on which they depend, and

to take steps to recover these species as

key components of America’s heritage. To

implement the ESA, we work in

cooperation with the National Marine

Fisheries Service, other Federal, State,

and local agencies, non-governmental

organizations, and you.

Before a plant or animal species can

receive the protection provided by the

ESA, it must first be added to the Federal

lists of threatened and endangered wildlife

and plants. The List of Endangered and

Threatened Wildlife, 50 CFR 17.11, and

the List of Endangered and Threatened

Plants, 50 CFR 17.12, contains the names

of all species of mammals, birds, reptiles,

amphibians, fishes, insects, plants, and

other creatures that have been

determined by us and the National Marine

Fisheries Service (for most marine life) to

be in the greatest need of Federal

protection.

What does “endangered” mean?

A species is listed under one of two

categories, endangered or threatened,

depending on its status and the degree of

threat it faces. An “endangered” species is

one that is in danger of extinction

throughout all or a significant portion of its

range. A “threatened” species is one that

is likely to become endangered in the

foreseeable future. To help conserve

genetic diversity, the ESA defines

“species” broadly to include subspecies,

and (for vertebrates) distinct populations.

The endangered tan riffleshell is one of

many species on the U.S. List of Endangered

and Threatened Wildlife and Plants. To see

what species are currently on the list, the

best place to look is on our web site at http://

endangered.fws.gov. USFWS photo

What is the criterion for deciding whether

to add a species to the list?

A species is added to the list when it is

determined to be endangered or

threatened because of any of the following

factors:

■ the present or threatened destruction,

modification, or curtailment of the species’

habitat or range;

■ overutilization for commercial,

recreational, scientific, or educational

purposes;

■ disease or predation;

■ the inadequacy of existing regulatory

mechanisms; or

■ other natural or manmade factors

affecting the species’ survival.

What steps are involved in listing a

species?

In order to list a species, we must follow a

strict legal process known as a “rulemaking

(or regulatory) procedure.” Federal

agencies follow this procedure to propose

and then adopt regulations that have the

effect of law and apply to all persons and

agencies under U.S. jurisdiction.

As a first step in assessing the status of a

species, we publish “notices of review”

that identify U.S. species that we believe

meet the definition of threatened or

endangered; we refer to them as

“candidates” for listing. Through notices of

review, we seek biological information that

will complete the status reviews for these

candidate species. These and all other

notices throughout the rulemaking

process are published in the Federal

Register, a daily Federal Government

publication. Our latest Candidate Notice of

Review is also available on our web site.

How do we decide which species to list?

Because of the large number of candidates

and the time required to list a species, we

developed a priority system designed to

direct our efforts toward the plants and

animals in the greatest need. In our

priority system, the degree or magnitude

of threat is the highest criterion, followed

by the immediacy of the threat and the

taxonomic distinctiveness of the species

(monotypic genus, then species, and lastly

subspecies, variety, or vertebrate

population). The ESA gives no preference

to popular species or so-called “higher life

forms.”

In some cases, we initiate conservation

activities for various candidate species

before listing. Candidate Conservation

Agreements are partnerships involving

the Fish & Wildlife Service and States or

territories, Federal agencies, private

agencies, and you or your neighbor to

reduce or remove the threats to species on

the brink of listing. This “preventive”

approach is taken for species that can

benefit from early recovery efforts, with

the goal of avoiding the need to formally

list the species at a later date.
How can you comment on a listing? 

Once a species is chosen for listing, we or 

the National Marine Fisheries Service (for 

most marine species) publish a proposed 

rule in the Federal Register. We sometimes 

publish multi-species proposals when 

several candidate species share a common 

ecosystem. At this stage, any interested 

person can comment and provide 

additional information on the proposal 

(generally during a 60-day comment 

period), and submit statements at any 

public hearings that may be held. 

To ensure that everyone is aware of a 

proposal, we issue news releases, conduct 

special mailings, and directly inform the 

scientific community and other Federal 

and State agencies. In addition, we publish 

a summary of any proposal as a legal 

notice in newspapers serving each area in 

which the species is believed to occur so 

that you can hear of our proposal. We may 

hold public hearings in cases of high public 

interest or if requested to do so within 45 

days of a proposal. 

What do you do with the comments and 

biological information? 

Information received in public comments 

and testimony is analyzed and considered 

in our final rulemaking process. Within one 

year of a listing proposal, one of three 

possible courses of action is taken: 

1) a final listing rule is published (as 

proposed or revised) because the best 

available biological data supports it; 

2) the proposal is withdrawn because the 

biological information on hand does not 

support the listing; or 

3) the proposal is extended (but only for an 

additional 6 months) because, at the end of 

one year, there is substantial disagreement 

within the scientific community concerning 

the biological appropriateness of the 

listing. After the extension, we must make 

a decision on the basis of the best scientific 

information available. 

If approved, the final listing rule generally 

becomes effective 30 days after publication 

in the Federal Register. After a species is 

listed, we review its status at least every 5 

years to determine if Federal protection is 

still warranted. 

Can I nominate a species for listing? 

Although we usually initiate listing 

proposals, we also may start the listing 

process with a petition from anyone. 

However, petitions need the support of 

adequate biological data. Any information 

submitted on the biology, distribution of, or 

threats to the species is taken into What does “listing” mean for a species? 

consideration in making our decisions. Once we add an animal or plant to the List, 

all protective measures authorized by the 

What are petitions for listing? ESA apply to the species and its habitat. 

Petitions are formal requests to list a Such measures include protection from 

species that require published findings. We adverse effects of Federal activities 

(or the National Marine Fisheries Service (through consultations under section 7 of 

for most marine species) must make a the ESA); restrictions on taking, 

finding within 90 days of receiving a transporting, or selling a species; authority 

petition (to the extent practicable) as to for us to develop and carry out recovery 

whether or not there is “substantial plans; authority to purchase important 

information” indicating that the petitioned habitat; and Federal aid to State and 

listing may be warranted. If this Commonwealth wildlife agencies that have 

preliminary finding is positive, a status cooperative agreements with us. These 

review is conducted. Within one year of efforts contribute to species survival and 

receipt of the petition, we must make a assist us in achieving our ultimate goals — 

further finding that the listing either is or to maintain the natural diversity of plants 

is not warranted. A positive one-year and animals and the ecosystems upon 

finding can be incorporated into a which they depend and to restore listed 

proposed listing or, if a prompt proposal is species to a level where protection is no 

precluded by other listing activities, the longer required. 

proposal may be deferred. These 

“warranted but precluded” proposals 

require subsequent one-year findings on U.S. Fish & Wildlife Service 

each succeeding anniversary of the petition Endangered Species Program 

until either a proposal is undertaken or a 703/358 2105 

“not warranted” finding is made. http://endangered.fws.gov 

February 2001