Red Knots live in dry vegetated and barren habitats in the Arctic, such as windswept ridges, slopes or plateaus. Their nests are usually placed in a small patch of vegetation within about 500 m of a pond, wetland or waterbody.
Red Knots typically arrive on the breeding grounds from late-May to early-June and begin laying their clutch of four eggs by mid to late-June. The eggs are incubated for a period of 21 to 23 days before the chicks hatch in mid-July.
Delaware Bay in New Jersey, U.S.A., is a critical northward migration stopover for rufa Red Knots. Their migration is timed to coincide with the spawning of Horseshoe Crabs. Horseshoe Crab eggs are a very important food source for migrating rufa Red Knots because the eggs, unlike any other food resource, are immediately metabolized into fat. The birds must double their weight at Delaware Bay to successfully continue their northward migration to the breeding grounds.