Rufa Red Knot
Northeast Region
Red knot Migration Miracle

Click to view the full size image
The Rufa Red Knot (Calidris canutus rufa) Red Knot Resources

Service Protects Red Knot as Threatened Species under Endangered Species Act

The rufa subspecies of the red knot now will receive protection as a threatened species under the Endangered Species Act, the Service announced today. “Unfortunately, this hearty shorebird is no match for the effects of widespread emerging challenges like climate change and coastal development, coupled with the historic impacts of horseshoe crab overharvesting, which have sharply reduced its population in recent decades,” said Service Director Dan Ashe.

News Release
Learn More
Final Rule
Supplemental Document

Additional information on the listing

On September 27, 2013, the Service released a proposal to list the rufa red knot as threatened under the Endangered Species Act, and submitted that determination to the Federal Register by the legal deadline of November 28. The Candidate Notice of Review published in the Federal Register on December 5, 2014, listed the rufa red knot as a candidate species. The rufa red knot will be removed from the candidate list upon the effective date of the final listing determination.

During more than 130 days of public comment periods and three public hearings since September 2013, the Service received more than 17,400 comments on the threatened listing proposal, many of which were supportive form letters, while others raised issues with the adequacy of horseshoe crab management, the impacts of wind turbines, the inclusion of interior states in the range, and other topics. The agency requested additional time to complete the final decision so that we could thoroughly analyze complex information available after the proposal, such as national and global climate assessments, and so that we could carefully consider and address extensive public comments. A thorough response to comments is included in the final document.

Archived documents and informational materials:

Rufa red knot proposed for "threatened" status under Endangered Species Act, Sept. 27, 2013

News release (PDF version)
Questions and answers (PDF version)
Proposed rule (PDF version)
Supplemental documents for the proposed rule: Previous federal actionsEcology and abundanceClimate changeInadequacy of existing regulatory mechanisms (PDFs)
ResourcesMapsmigration infographicvideo and photos

Proposed rule and all supplemental documents are also available at by entering docket number FWS-R5-ES-2013-0097Comments submitted during the comment period are posted in that docket.

The Service reopened the comment period April 3, 2014, for listing the rufa red knot as threatened, and later extended that reopening through June 15, 2014. These materials reference an interim estimate of more than 560 individual comments and 19,000 form letters. The final actual count is more than 17,400 comments.

News release (online version) (PDF version)
Questions and answers (PDF version)
Federal Register notice for reopening
Federal Register notice for extending reopening

Red knot information

The rufa red knot is truly a master of long-distance aviation. On wingspans of 20 inches, some knots fly more than 9,300 miles from south to north every spring and repeat the trip in reverse every autumn, making this bird one of the longest-distance migrants in the animal kingdom. Surveys of wintering knots along the coasts of southern Chile and Argentina and during spring migration in Delaware Bay on the U.S. coast indicate that a serious population decline occurred in the 2000s.

The knot’s unique and impressive life history depends on suitable habitat, food and weather conditions at far-flung sites across the Western Hemisphere, from the extreme south of Tierra del Fuego to the far north of the central Canadian Arctic. Knots need to encounter these favorable habitat, food and weather conditions within narrow seasonal windows as the birds hopscotch along migration stopovers between wintering and breeding areas. For example, the knot population decline that occurred in the 2000s was caused primarily by reduced food availability from increased harvests of horseshoe crabs, exacerbated by small changes in the timing that knots arrived at the Delaware Bay. Horseshoe crab harvests are now managed with explicit goals to stabilize and recover knot populations.

Knots may be particularly vulnerable to climate change, which is likely to affect:

  • the arctic tundra ecosystem where the knots breed;
  • coastal habitats due to rising sea levels;
  • food resources throughout the bird’s range; and
  • storm and weather patterns.

Knot numbers appear to have stabilized in the past few years, but they remain at low levels relative to earlier decades. Biologists from the U.S. Fish and Wildlife Service, state natural resource agencies, and non-profit organizations all share a concern for this race of red knot and are pooling efforts to identify what needs to be done to prevent further losses. Together with these partners, the U.S. Fish and Wildlife Service is dedicated to working to conserve this extraordinary bird.

Facts about the red knot (PDF)
Red knot species profile (Petitions, status reviews and conservation documents)
New Jersey Field Office red knot page
Shorebirds: The Delaware Bay Connection (PDF) Facts about horseshoe crabs (PDF)
Atlantic Flyway Shorebird Conservation Business Strategy

Report sightings, for shorebirds with colored bands/lettered flags, for bird sightings

See Ebird map for all red knot subspecies

Red knot photos Red knot maps
Red knot video Red knot blog
Top Red Knot News

Associated Press: Experts fire cannons to save elusive shorebirds (story) (video)

McClatchy News: Scarlet shorebird serves as harbinger of climate change between the poles

Cape Cod Times: Researchers in Chatham try to band birds

New York Times: Red knots, horseshoe crabs and fight to survive in Delaware Bay

Philadelphia Inquirer: Report from the Bay: Red knots at 26,000

Last updated: August 22, 2018