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the web of life in southern Africa

Calidris canutus (Red knot, Common knot) 

Knoet [Afrikaans]; IJslandse kanoetstrandloper [Dutch]; Bécasseau maubèche [French]; Knutt [German]; Seixoeira [Portuguese]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Tetrapoda (four-legged vertebrates) > Reptiliomorpha > Amniota > Reptilia (reptiles) > Romeriida > Diapsida > Archosauromorpha > Archosauria > Dinosauria (dinosaurs) > Saurischia > Theropoda (bipedal predatory dinosaurs) > Coelurosauria > Maniraptora > Aves (birds) > Order: Charadriiformes > Family: Scolopacidae

Calidris canutus (Red knot, Common knot)   

Red knot, West Coast National Park, South Africa. [photo Trevor Hardaker ©]

 

Distribution and habitat

Breeds in the Arctic tundra mainly above 70° North, heading south in the non-breeding season to Europe, South-East Asia, Australasia, Central and South America and Africa's west coast from Mauritania through West Africa to southern Africa. Here it is locally fairly common along the west coast from Namibia to the Cape Peninsula, Western Cape, while more scarce further east in the Eastern Cape and KwaZulu-Natal. It generally prefers large mud and sand flats in sheltered coastal lagoon and embayments, occurring less regularly in coastal wetlands, estuaries and open coasts.

Distribution of Red knot in southern Africa, based on statistical smoothing of the records from first SA Bird Atlas Project (© Animal Demography unit, University of Cape Town; smoothing by Birgit Erni and Francesca Little). Colours range from dark blue (most common) through to yellow (least common). See here for the latest distribution from the SABAP2.  

Predators and parasites

  • Predators
  • Parasites
    • Cylocoelum mutabile (lung trematode)

Movements and migrations

Departs from its breeding grounds in July to head down the east Atlantic seaboard and eventually reaching southern Africa from September-October, leaving again in mid April. It is capable of flying non stop for over 4000 km's, although some birds may be incapable of making the journey back  to the breeding grounds and so stay in southern Africa through winter. The proportion of juveniles in the region is linked to the abundance of lemmings (Dicrostonyx torquatus and Lemmus sibiricus) at its breeding colonies, as they are the main prey of Arctic foxes (Alopex lagopus). About every third year lemmings are much more scarce, so the foxes resort to feeding on the chicks of ground-nesting birds, including the Red knot. This means that that juveniles represent 24-61% of all the Red knots at Langebaan Lagoon in normal years, but when lemmings are scarce the proportion of juveniles is just 0-7%.

Food 

It mainly eats bivalves, especially Tellimaya trigona, supplemented with other molluscs (including the snail Hydrobia), polychaetes, crustaceans and echnoderms, doing most of its foraging by pecking the ground or probing the mud while moving forwards. It often joins mixed species flocks along with other waders, such as Curlew sandpipers and Little stints.

Threats

Not threatened, although global climate change is predicted to result in the loss of 15% of its breeding habitat.

References

  • Hockey PAR, Dean WRJ and Ryan PG 2005. Roberts - Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.