Red Knot

Calidris canutus

Order CHARADRIIFORMES - Family SCOLOPACIDAE - Subfamily Scolopacinae

Menu

1. Cool Facts
2. Description
3. Sound
4. Range
5. Habitat
6. Food
7. Behavior
8. Reproduction
9. Conservation Status
10. Other Names

The Red Knot is the largest of the "peeps" in North America, and one of the most colorful. It makes one of the longest yearly migrations of any bird, traveling 15,000 km (9,300 mi) from its Arctic breeding grounds to Tierra del Fuego in southern South America.

Cool Facts

• The Red Knot does not regurgitate undigested hard parts of prey, as do many species of birds. Instead it excretes the hard parts in the feces. Researchers have used fecal content to examine food consumption rates.

• Red Knots concentrate in huge numbers at traditional staging grounds during migration. Delaware Bay is an important staging area during spring migration, where the knots feed on the eggs of spawning horseshoe crabs. It is estimated that nearly 90 percent of the entire population of the Red Knot subspecies C. c. rufa can be present on the bay in a single day. The reduction in food available to the knots because of the heavy harvesting of horseshoe crabs may be responsible for a decline in Red Knot populations.

Description

• Size: 23-25 cm (9-10 in)
• Wingspan: 52-56 cm (20-22 in)
• Weight: 135 g (4.77 ounces)

• Large, bulky sandpiper.
• Relatively short, straight bill tapering to tip.
• Legs short and thick.
• Head and breast reddish in breeding plumage, gray the rest of the year.

• Underwing gray.
• Moderate white wing stripe in flight.
• Often found foraging and roosting in very large flocks.
  
  Breeding (Alternate) plumage: Head, neck and breast red (salmon to brick red). Light lower belly and under tail. Gray back, with some rust-colored spots.
  Winter (Basic) plumage: Plain gray above. Rump and lower back pale gray, blending with tail. Underparts dull white with some dark vertical streaking on upper breast that may extend to the flanks.

Sex Differences

Sexes look similar.

Female

In breeding plumage female has light-colored feathers amongst the belly feathers and less distinct eyeline. Sexes appear similar in winter. Female has slightly longer wings and bill.

Immature

Similar to adult winter plumage, but gray back feathers outlined in white and black, giving a scaly appearance.

Sound

Usually quiet away from breeding grounds, but may make a subdued, somewhat nasal whine that increases in strength and scale for about one second. Also a two-part "knuup-knuup" in flight. Display song is moaning, flutelike repeated "poorr-mee."

»listen to songs of this species

Range

Summer Range

Breeds in extreme northern Alaska and Canada. Also breeds in northern Greenland and Russia.

Winter Range

Winters very locally at coastal sites from California and Massachusetts southward to southern South America. Also from Europe to Africa, Asia, and Australia.

Habitat

• Breeds in drier tundra areas, such as sparsely vegetated hillsides.
• Outside of breeding season, it is found primarily in intertidal, marine habitats, especially near coastal inlets, estuaries, and bays.

Food

Invertebrates, especially bivalves, small snails, and crustaceans. During breeding season, also eats terrestrial invertebrates.

Behavior

Foraging

Pecks at surface prey or probes for buried prey. Swallows small mollusks whole.

Courtship

Male makes an aerial singing display.

Other Behavior

Despite their gregariousness during the winter, pairs maintain breeding territories and generally nest about 1 km (0.7 mi) apart from each other.

Reproduction

Nest Type

Cup-shaped depression on ground. Lined with dried leaves, grasses, and lichens.

Egg Description

Faint olive to deep olive-buff with dark markings, denser at large end.

Clutch Size

Usually 4 eggs.

Condition at Hatching

Downy young leave nest almost immediately.

Conservation Status

Occurrence of large concentrations of knots at traditional staging areas during migration makes them vulnerable to pollution and loss of key resources. Numbers appear to be decreasing; the populations wintering in South America dropped over 50% from the mid-1980s to 2003.

Other Names

Bécasseau maubèche (French)

Sources used to construct this page:

1. Harrington, B. A. 2001. Red Knot (Calidris canutus). In The Birds of North America, No. 563 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
2. Morrison, R. I. G., R. K. Ross, and L. J. Niles. 2004. Declines in wintering populations of Red Knots in southern South America. Condor 106: 60-70.