Red Knot (Calidris canutus rufa) [candidate]
The rufa subspecies of the red knot was added to the list of Federal candidate species in 2006 due to the high magnitude of imminent threats to the subspecies, and the Service is currently determining whether to designate it as threatened or endangered. Since 2006, listing has been precluded by other, higher priority listing actions. The Service is now preparing a Proposed Rule to list the species as either threatened or endangered. The Service must also consider whether there are areas of habitat believed to be essential to red knot conservation. If prudent and determinable, those areas will be proposed for designation as Critical Habitat. The Service has authority to designate Critical Habitat only within the U.S. and its territories. We anticipate that the Proposed Rule / Proposed Critical Habitat will be published in the Federal Register by late 2012 for public comment.
The red knot was added to the list of Federal candidate species in 2006. Red knots are federally protected under the Migratory Bird Treaty Act, and are State-listed as threatened.
At 9 to 10 inches long, the red knot is a large, bulky sandpiper with a short, straight, black bill. During the breeding season, the legs are dark brown to black, and the breast and belly are a characteristic russet color that ranges from salmon-red to brick-red. Males are generally brighter shades of red, with a more distinct line through the eye. When not breeding, both sexes look alike—plain gray above and dirty white below with faint, dark streaking. As with most shorebirds, the long-winged, strong-flying knots fly in groups, sometimes with other species. Red knots feed on invertebrates, especially bivalves, small snails, crustaceans, and, on breeding grounds, terrestrial invertebrates.
Small numbers of red knots may occur in New Jersey year-round, while large numbers of birds rely on Atlantic and Delaware Bay stopover habitats during the spring (mid-May through early June) and fall (late-July through October) migration periods. Red knots winter at the southern tip of South America and breed above the Arctic Circle. These small shorebirds fly more than 9,300 miles from south to north every spring and reverse the trip every autumn, making the red knot one of the longest-distance migrating animals. Migrating red knots break their spring migration into non-stop segments of 1,500 miles or more, converging on just a few critical stopover areas along the way. Large flocks of red knots arrive at stopover areas along the Delaware Bay and Atlantic coast each spring, with many of the birds having flown directly from northern Brazil. Red knots are faithful to these specific sites, stopping at the same locations year after year. The spring migration is timed to coincide with the spawning season for the horseshoe crab (Limulus polyphemus). Horseshoe crab eggs provide a rich, easily digestible food source for migrating birds. Mussel beds are also an important food source for migrating knots, particularly if insufficient horseshoe crab eggs are available. Birds arrive at stopover areas with depleted energy reserves and must quickly rebuild their body fat to complete their migration to Arctic breeding areas. During their brief 10 to 14-day stay in the mid-Atlantic, red knots typically double their body weight.
Threats to the red knot include disturbance, reduced food availability at stopover areas, and shoreline development.
Candidate species are species that the U.S. Fish and Wildlife Service (Service) has determined warrant listing under the Endangered Species Act and await formal listing. Although these species receive no substantive or procedural protection under the Endangered Species Act until formal listing, the Service encourages consideration of candidate species in project planning.
Species Range: Red knots migrate along the Atlantic coast of the United States, where they may be found from Maine to Florida.
Distribution in New Jersey: Transient red knots may be found anywhere along New Jersey's coasts. Concentrations of migrating birds are known to occur in Cumberland, Cape May, and Atlantic Counties. See Federally Listed Species Occurrences by Municipality and County [PDF].