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. Nests are extremely hard to find because knots are well camouflaged and do not leave the nest, even when approached.
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 chick hatch in mid-July.
To prepare for migration to their breeding grounds, Red Knots increase the size of the parts of their body used for flying (heart and flight muscles) and decrease the size of the parts not used for flight (digestive system). Once they arrive on their breeding grounds, their reproductive organs increase in size and their heart and flight muscles decrease to normal size.