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The Red Knot (Calidris canutus) has been identified as a focal species due to drastic declines in populations of North American subspecies, especially rufa whose population has declined by more than 75% within the past 20 years. A long-distance migrant that breeds in the Arctic, some knots winter along the coast of the southeastern U.S. while others migrate to the southern tip of South America. Their annual migrations are completed through a series of flights, each of which may cover thousands of kilometers and require abundant food supplies to build up the necessary energy resources to fuel these flights. Delaware Bay is a well-know spring stopover site for migrating Red Knots, where the birds feed on horseshoe crab eggs to rapidly gain weight for the next leg of their journey to their Arctic breeding grounds. This sandpiper is vulnerable during migration due to loss of important food sources, such as the overharvesting of horseshoe crabs in Delaware Bay, and also to disturbance and habitat loss at stopover sites. Decreased foraging success during migration has been linked to decreased breeding success and the probable increased mortality of adults. Wintering knots tend to concentrate at a few localities where habitat loss or reduced food availability can influence a sizable proportion of entire populations. Additionally, climate change may have long-term effects on its coastal foraging areas due to sea level rise and its Arctic breeding grounds due to habitat change.
Date: March 2008
Sources: Baker AJ, Gonzalez PM, Perisma T, Niles LJ, I de LS do Nascimento LJ, Atkinson PW, Clark NA, Minton CDT, Peck M, Aarts G. 2004. Rapid population decline in Red Knots: Fitness consequences of decreased refuelling rates and late arrival in Delaware Bay. Proceedings of the Royal Society of London, Series B. 271:875-882.
Harrington, BA. 2001. Red Knot (Calidris canutus). In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. Retrieved from http://bna.birds.cornell.edu/bna/species/563/articles/introduction.
Species Profile from NatureServe
Red Knot Calidris canutus
Description: A bird (sandpiper).
Life History: Lays clutch of usually 4 eggs, June-July. Incubation lasts about 20-25 days, by both sexes. Young are tended mostly by male (female leaves before fledging), leave nest soon after hatching, can fly at about 18 days (Terres 1980).
Migrates in large flocks northward through contiguous U.S. mainly April-June, southward July-October (Bent 1927). Arrives in breeding areas late May or early June; most have departed breeding areas by mid-August. More abundant in migration along U.S. Atlantic coast than on Pacific coast. Knots that visit Delaware Bay in spring come mostly from South America, and these have strong fidelity to migration stopover sites; those that winter in Florida are underrepresented during migration in New Jersey and Massachusetts. Migrates through Costa Rica late August-October and mainly mid-March to late April (Stiles and Skutch 1989). Typically makes long flights between stops (Hayman et al. 1986). See Piersma and Davidson (1992) for information on knot migration.
Habitat:Primarily seacoasts on tidal flats and beaches, less frequently in marshes and flooded fields (AOU 1983). On sandy or pebbly beaches, especially at river mouths; feeds on mudflats, loafs and sleeps on salinas and salt-pond dikes (Costa Rica, Stiles and Skutch 1989). Nests on ground in barren or stony tundra and in well-vegetated moist tundra.
Distribution:
United States: AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, WA, WI, WY
Canada: AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, SK
Status:
NatureServe Status: Global Status: G4, Global Status Last Reviewed: 04Oct2005, Global Status Last Changed: 04Oct2005, Rounded Global Status: G4 - Apparently Secure
Other Statuses: IUCN Red List Category: LC - Least concern
