What are the differences between endangered, threatened, imperiled, and at-risk species?

Under the Endangered Species Act (ESA), plant and animal species may be listed as either endangered or threatened. “Endangered” means a species is in danger of extinction throughout all or a significant portion of its range. “Threatened” means a species is likely to become endangered within the foreseeable future.'

States have their own ESA-type laws, so species can have different Threatened/Endangered statuses at the federal and state levels. The USGS typically refers to the federal status unless otherwise noted.

"Imperiled" or "at risk" are not legal terms under ESA, but more biological terms. Generally speaking, they are animals and plants that are in decline and may be in danger of extinction. Those terms can include species that are at low populations and near extinction but still not legally protected under ESA.

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What is the threat from West Nile Virus (WNV) to endangered and threatened bird species?

This is an issue of great concern, as these populations are already struggling to survive in the current environment. If some of these species are more vulnerable to fatal WNV infection, WNV may ultimately lead to their extinction or significantly set back the progress of the recovery programs.

Where are salmon most endangered?

Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are...

Are salmon endangered worldwide?

No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park.

Why do animals and plants become endangered?

Generally speaking, endangered species are those animals and plants that are in decline and may be in danger of extinction. A threatened species is one that is likely to become endangered within the foreseeable future.
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Date published: January 19, 2018

Scientists, volunteers rescue about 1,000 cold-stunned sea turtles

Florida's second-largest turtle rescue of 21st century is “exhausting, inspiring,” USGS biologist says

Date published: February 2, 2017

A Century of Habitat Loss Affects Genetics of Endangered Bird

A new study analyzes the genetic diversity and population structure of the California Ridgway’s rail, Rallus obsoletus, a state and federally-listed endangered bird. The results demonstrate that the so-called “rails” are experiencing negative genetic effects following more than a century of salt marsh habitat loss from agriculture, commercial salt production and urban development.

Date published: February 2, 2017

A Century of Habitat Loss Affects Genetics of Endangered Bird

A new study analyzes the genetic diversity and population structure of the California Ridgway’s rail, Rallus obsoletus, a state and federally-listed endangered bird. The results demonstrate that the so-called “rails” are experiencing negative genetic effects following more than a century of salt marsh habitat loss from agriculture, commercial salt production and urban development.

Date published: August 20, 2016

Drought and Wildfires Threaten the Endangered Mountain Yellow-Legged Frog (Los Angeles Times)

SOUTHERN CALIFORNIA — Wildfires are affecting endangered Mountain yellow-legged frogs in San Diego and other counties.

Date published: April 20, 2016

Community flood protection may also help endangered salmon to thrive

Building a river setback levee to reduce the risk of flood for a community may also help endangered fish species to thrive, according to the results of a novel computer model reported by the U.S. Geological Survey. 

Date published: January 22, 2016

Magical Manatees

It may be hard to believe the legend that sailors long-at-sea once believed manatees to be mermaids. The manatee nickname the “Sea Cow” – named so for their affinity for grazing on vegetation and their slow, ambling way – just makes more sense. But a new U.S. Geological Survey video reveals that while they may be cow-like, they also have more than a bit of magical mermaid to them.

Date published: May 20, 2015

Long-term Prognosis for Florida Manatees Improves

The risk of extinction for the endangered Florida manatee appears to be lower, according to a new U.S. Geological Survey led study.

Date published: January 23, 2015

Culprit Identified in Decline of Endangered Missouri River Pallid Sturgeon

BOZEMAN – Pallid sturgeon come from a genetic line that has lived on this planet for tens of millions of years; yet it has been decades since anyone has documented any of the enormous fish successfully producing young that survive to adulthood in the upper Missouri River basin.

Date published: September 23, 2014

Captive Whooping Cranes Released Into the Wild

Four whooping crane chicks raised in captivity began their integration into the wild Saturday as part of the continuing effort to increase the wild population of this endangered species.

Date published: June 29, 2007

Endangered Desert Pupfish found in Research Ponds near the Salton Sea, Calif.

Researchers from the U.S. Geological Survey (USGS) have discovered a population of the endangered desert pupfish (Cyprinodon macularius)in constructed ponds along the southeastern shore of the Salton Sea, in south-central California.

Date published: July 9, 1999

A First: Endangered Puaiohi Birds Fledge Four Chicks in the Wild

A highly endangered native Hawaiian bird species has taken a small but significant step back from the brink of extinction. USGS biologists monitoring 14 captive-reared puaiohi released into the wild earlier this year by The Peregrine Fund say the birds are nesting and have already fledged four young.

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Humpback chub fish
December 22, 2016

Endangered Humpback Chub

Endangered humpback chub caught near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon.

Close-up of a small Pima pineapple cactus in coarse-textured soil in the desert.
December 14, 2016

Pima pineapple cactus

Pima pineapple cactus and vegetative offshoot, commonly called a pup, in the Altar Valley of south-central Arizona (November 2014).

A green and black endangered Sonoran tiger salamander on a tree branch
August 18, 2016

Endangered Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi)

A green and black endangered Sonoran tiger salamander (Ambystoma mavortium stebbinsi) on a tree branch

Image: An Endangered Puaiohi (Small Mountain Thrush) in Hawaii
March 14, 2016

An Endangered Puaiohi (Small Mountain Thrush) in Hawaii

Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum). Malaria transmission is tied closely to the effects of temperature on development of malarial parasites within their mosquito

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Image: Green Sea Turtle Swimming in Dry Tortugas National Park
July 7, 2012

Green Sea Turtle Swimming in Dry Tortugas National Park

A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles. The activity

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Image: Female Pallid Sturgeon
June 19, 2012

Female Pallid Sturgeon

Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred.  Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.

Image: An Endangered Yellow-Legged Frog
May 19, 2011

An Endangered Yellow-Legged Frog

USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.

Image: An Endangered Humpback Chub
May 19, 2011

An Endangered Humpback Chub

The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population. The number Grand

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