The red knot, or Calidris canutus, is a type of sandpiper, or small shorebird, with stick-like legs. Red knots have gray wings with white stomachs, and the plumage on their chest and neck turns red during breeding season. Red knots are especially notable because of their long migration routes, which encompass more than 9,300 miles (14,967 km) a year.
Red knots are roughly 9 inches (23 cm) long and can be found on sandy shorelines and in shallow wetlands from the Arctic Circle, where their breeding grounds are located, to the southern tip of South America. Their diet mainly consists of insects, snails, crustaceans and mollusks, yet they eat seeds and grasses when these more nutritious foods are unavailable. Red knots are built for life near beaches or shallow waters, and their thin legs allow them to easily navigate through water.
Perhaps the red knot is most known for its long migration route — more than 9,300 miles (14,967 km) each year; it’s one of the longest migration routes of any animal. Red knots fly every spring and fall between their breeding grounds in the Arctic Circle and various southern points to spend their winters along shorelines as far away as South America. Red knots travel in flocks much larger than those of typical migrating birds. It is believed this is meant as a protective measure, yet this habit puts a great number of birds at risk when habitat is threatened and when toxins or other environmental threats enter their environment.
Red knots rest along their migration route at locations called “staging areas.” The birds remember these staging areas from year to year and visit the same location every time they travel. Perhaps the most significant of these staging areas is around the Delaware Bay, along the eastern coast of the United States. The birds time their arrival at this staging area to coincide with the release of horseshoe crab eggs, which provide the birds with much needed nourishment.
The number of red knots has declined, and these birds are now listed as a “species of high concern” by the United States Shorebird Conservation Plan. This decline may be attributed to several factors, including climate change threatening the red knot’s breeding grounds in the Arctic Circle. The number of horseshoe crabs along the bird’s Delaware Bay staging area is also in decline because of overharvesting in the 1990s, when fishermen often used horseshoe crabs as bait. The crab’s decline, along with being a problem for the horseshoe crab population, also threatens the red knot by affecting one of the bird’s most important staging areas.