Red Knot

Calidris canutus

(c) Howard B. Eskin
  • Snipe, Sandpipers, Phalaropes, and allies
  • Charadriiformes
  • Playero canuto, Chorlo rojizo
  • Bécasseau maubèche
The Red Knot in non-breeding plumage is quite a drab shorebird. Yet in breeding plumage, with its russet head and breast, it is one of North America's most colorful sandpipers. During migration, Red Knots concentrate in huge flocks at traditional staging grounds in both South and North America to fatten up before embarking on one of the longest annual migrations of any bird.
(c) Howard B. Eskin
Appearance Description
This large, bulky sandpiper is about 10 inches long and weighs 4.8 ounces, with a wingspan of 22 inches. Sexes look similar. The Red Knot's legs are short and thick, and its bill short and straight. The head and breast, while gray most of the year, are reddish in breeding plumage.
Range Map
Courtesy Kenn Kaufman
Range Distribution
Red Knots breed in extreme northern Alaska, Canada, northern Greenland, and Russia. They winter locally at coastal sites from California and Massachusetts in the U.S., and southward to southern South America, as well as from Europe to Africa, Asia, and Australia.
A legend for the range map to the right can be found here.
Red Knots breed in dry tundra areas, such as sparsely vegetated hillsides. Outside of the breeding season, knots are found primarily in intertidal marine habitats, especially near coastal inlets, estuaries, and bays.
In the non-breeding season, Red Knots feed principally on marine invertebrates such as small snails, crustaceans, and especially, small mollusks swallowed whole. The huge flocks that gather during spring migration on Delaware Bay gorge as well on the horseshoe crabs eggs laid in late May. These birds also eat plant material early in the breeding season, when insects are scarce. During breeding season, the knots eat a variety of terrestrial invertebrates, either pecking at surface prey or probing for buried prey. Instead of regurgitating indigestible parts of prey, as do many bird species, the Red Knot excretes these parts in the feces. Researchers have used fecal content to examine food consumption habits.
Male Red Knots display with aerial singing. Despite their winter flocking behavior, pairs maintain breeding territories and nest about three quarters of a mile apart from each other. The nest is a cup-shaped depression on ground lined with dried leaves, grasses, and lichens. The female lays four olive-colored eggs with brown markings. The downy young leave the nest almost immediately.
The species' five recognized subspecies breed around the Arctic polar regions, in some of the coldest regions of the earth, then winter in some of the hottest. Each subspecies has slightly different physical features but strikingly different migration strategies; one subspecies travels 9,300 miles from its Arctic breeding grounds to Tierra del Fuego in southern South America. The species is well suited for studying the development of avian migration, and the development of conservation strategies for long-distance migrants.
  • 1,100,000
  • 400,000
  • Severe population declines; very high threats
Population Status Trends
Red Knot numbers are rapidly decreasing; populations wintering in South America have dropped over 50 percent from the mid-1980s to 2003. The knot is listed by the Fish and Wildlife Service as a Bird of Conservation Concern, and is considered a Continentally Threatened Species. Christmas Bird Count data also show declines. Most recently, it has been listed as a candidate species for the Endangered Species List.
Conservation Issues
Red Knots were heavily hunted for both market and sport during the late 1800s and early 1900s. Today, their tendency to concentrate at traditional coastal staging sites during migration makes these birds vulnerable to the loss of key resources. Delaware Bay, on the mid-Atlantic Coast, is one such area; here the knots feed on the eggs of spawning horseshoe crabs. An estimated 90 percent of the entire population of the Red Knot subspecies C. c. rufa may be found on the bay in a single day.
The food available at this critical area has been greatly diminished by the annual killing of millions of horseshoe crabs to provide bait for American eel and, to a lesser extent, conch fisheries on the mid-Atlantic coast, contributing to the rapid decline in Red Knot populations. Regulatory initiatives to limit the horseshoe crab harvest were implemented in New Jersey and Delaware in the late 1990s, and recently, both states have prohibited the harvesting of horseshoe crabs.
Global warming may particularly impact this species, as it is expected to be greatest at polar latitudes, where Red Knots breed.
Knots and other shorebirds depend upon using quiet intertidal beach locations as resting sites during higher tides. Chronic human disturbance may limit their ability to gain the fat essential for migration.

Key to conservation efforts is the identification and protection of important Red Knot migration staging and wintering areas—among other steps, by including these habitats in the Western Hemisphere Shorebird Reserve Network. In southernmost Brazil, a major migration staging area of knots at Lagoa do Peixe—a reserve site—has been made a national park by the Brazilian government. In South Carolina, Audubon has promoted public education as a means of reducing shorebird disturbance by beach-walkers.

What You Can Do
Keep a safe distance from knots and other shorebirds on beaches—if the birds run or flush, you are too close. Avoid allowing unleashed dogs on these beaches. Sound, effective coastal habitat protection is essential to the knots' well-being.
Join beach cleanups in your area. Cutting up and properly discarding monofilament fishing line will prevent Red Knots and other seabirds from becoming entangled in it.
Work with regional planners to protect essential shorebird nesting and migration habitats. Opportunities for proactive management through creation of resting and nesting areas may exist with agencies such as the Army Corps of Engineers.
Don't discard used oil into city sewers. It can end up on the coasts where Red Knots rest and feed; if their feathers become oiled, the birds are no longer waterproof and cannot survive.
Use alternatives to pesticides, and dispose of pesticides responsibly. Pesticides can wash into the sea, potentially affecting the Red Knot's reproduction. Learn about healthier pest control at Audubon at Home:
Make environmentally-friendly seafood choices, which helps protect the marine life that Red Knots depend upon.
For more actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
Harrington, B. A. 2001. Red Knot (Calidris canutus). In The Birds of North America, No. 563 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York, 1996
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, Inc., New York, 2000
Conservation Status References
Harrington, B. A. 2001. Red Knot (Calidris canutus). In The Birds of North America, No. 563 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York, 1996
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, Inc., New York, 2000