- 9.1–9.8 in
- 20.5–22 in
- 4.8 oz
- Bécasseau maubèche (French)
- The Red Knot does not regurgitate undigested hard parts of prey, as do many species of birds. Instead it excretes the hard parts in the feces. Researchers have used fecal content to examine food consumption rates.
- Red Knots concentrate in huge numbers at traditional staging grounds during migration. Delaware Bay is an important staging area during spring migration, where the knots feed on the eggs of spawning horseshoe crabs. It is estimated that nearly 90 percent of the entire population of the Red Knot subspecies C. c. rufa can be present on the bay in a single day. The reduction in food available to the knots because of the heavy harvesting of horseshoe crabs may be responsible for a decline in Red Knot populations.
- The oldest recorded Red Knot was at least 15 years, 11 months old. It was banded in 1986 in New Jersey and recaptured and rereleased during banding operations in Delaware in 2001.
- Breeds in drier tundra areas, such as sparsely vegetated hillsides.
- Outside of breeding season, it is found primarily in intertidal, marine habitats, especially near coastal inlets, estuaries, and bays.
Invertebrates, especially bivalves, small snails, and crustaceans. During breeding season, also eats terrestrial invertebrates.
- Egg Description
- Faint olive to deep olive-buff with dark markings, denser at large end.
- Condition at Hatching
- Downy young leave nest almost immediately.
Cup-shaped depression on ground. Lined with dried leaves, grasses, and lichens.
Male makes an aerial singing display. Pecks at surface for prey or probes for buried prey. Swallows small mollusks whole. Despite their gregariousness during the winter, pairs maintain breeding territories and generally nest about 1 km (0.7 mi) apart from each other.
Red Knot is a global species. There are three subspecies in North America, and they all appear to be in decline. The populations wintering in South America dropped over 50% from the mid-1980s to 2003, and are listed as a federally threatened species in the U.S. A 2012 study estimated the total number of all three North American subspecies at about 139,000 breeding birds. North American Red Knot is on the 2014 State of the Birds Watch List, which lists bird species that are at risk of becoming threatened or endangered without conservation action. The IUCN Red List lists Red Knot as a Near Threatened species. The occurrence of large concentrations of knots at traditional staging areas during migration makes them vulnerable to pollution and loss of key resources.
- 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.
- Andres, B.A., P.A. Smith, R.I.G. Morrison, C.L. Gratto-Trevor, S.C. Brown, and C.A. Friis. 2012. Population estimates of North American Shorebirds, 2012. Wader Study Group Bulletin 119:178–194. Available from the U.S. Shorebird Conservation Plan website.
- BirdLife International. 2015. Calidris canutus. The IUCN Red List of Threatened Species 2015: e.T22693363A83036627
- Morrison, R. I. G., R. K. Ross, and L. J. Niles. 2004. Declines in wintering populations of Red Knots in southern South America. Condor 106: 60-70.
- U.S. Fish & Wildlife Service, ECOS-Environmental Conservation Online System, Red Knot (Calidris canutus rufa).
- USGS Patuxent Wildlife Research Center. 2015. Longevity records of North American Birds.