Calidris canutus
Red Knot
The Red Knot is a medium-sized shorebird with a distinctive plumage that changes dramatically between seasons.
In breeding plumage, it displays a striking rusty-red face, breast, and underparts, contrasting with its grey back and wings. Breeding females are similar to males, although their plumage is less vibrant, with less red colouring.
During non-breeding seasons, Red Knots transform to a plain grey above and white below. During this time, males and females are alike. They have a straight black bill and short, dark legs. Juveniles resemble non-breeding adults but with scaly patterning on their backs.
Length
23cm to 26cm
Wingspan
45cm to 54cm
Weight
100g to 200g
Males and females have similar plumage
Primary Colour
Red Grey
Secondary Colour
White
Beak Colour
Black
Leg Colour
Black
Woodland
Garden
Wetland
Coastal
Urban
Farmland
Grassland
Desert
Tundra
Rainforest
Mountain
Savanna
Red Knots breed in the high Arctic tundra and winter on coastal areas across the globe. They can be found on every continent except Antarctica during different parts of their annual cycle.
In North America, they are common along both coasts during migration. Key stopover sites include Delaware Bay in the USA and the Bay of Fundy in Canada.
They also frequent coastal areas in the UK, Australia, and New Zealand during non-breeding seasons.
Sea level to 300 meters
Arctic, Temperate, Tropical
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Red Knots primarily feed on small invertebrates, including molluscs, crustaceans, marine worms and spiders.
During migration, they rely heavily on horseshoe crab eggs in some regions, with Delaware Bay being a significant stopover point on northward migrations each spring.
Early arrivals to breeding grounds may eat shoots and plant matter if the landscape is not fully thawed for insect life to be widely available.
Their bills are specially adapted to probe for prey in sand and mud, often feeding in large groups during low tide.
Red Knots are known for their impressive long-distance migrations, flying up to 30,000 km (around 18,600 miles) annually. They often gather in large flocks, probing the sand or mud with their bills to find food.
During the breeding season, males perform aerial displays, flying in wide circles while calling to attract females.
Red Knots are usually silent when foraging alone, but they have a distinctive call, often described as a soft, low 'knut-knut' or 'tut-tut'.
During the breeding season, males produce a more melodious song, a series of fluty whistles that sound like 'tu-li-li-li', often given during display flights over their territories.
Red Knots breed in the Arctic tundra during the brief summer. Males arrive first and establish territories, performing aerial displays to attract females.
Nests are simple scrapes on the ground, often lined with leaves and lichen. Females typically lay 4 olive-green eggs with brown spots. Both parents share incubation duties.
The incubation period lasts about 22 days, and chicks are precocial, able to leave the nest and feed themselves shortly after hatching. They fledge after about 18-20 days.
The Red Knot typically lives for 8 to 10 years, with a maximum recorded lifespan of 27 years.
Like all birds, lifespan can be affected by factors including predation, habitat quality, disease, and access to food sources.
Red Knots face significant conservation challenges due to habitat loss and climate change. Overharvesting of horseshoe crabs, a key food source during migration, has impacted some populations.
Conservation efforts focus on protecting critical stopover sites and regulating horseshoe crab harvests.
Knot, Lesser Knot
Red Knots face predation from various species, including Arctic foxes, jaegers, and large gulls on their breeding grounds. During migration and winter, falcons and other raptors pose threats.
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Red knots are fascinating to researchers who are able to gain valuable insights into their lengthy migration patterns due to banding programs which are used to understand trends in population decline and changes to habitats worldwide.
Due to the vast numbers that descend upon Delaware Bay each year to feed on the eggs of horseshoe crabs, the species is directly linked to bringing in a significant amount of money to the local economy, with ecotourism in this region raising around $36 million annually.
Moonbird is the nickname given to an individual red knot, tagged as B95, which is the oldest known individual of its species and the subject of books and documentaries.
The nickname ‘moon bird’ originates from the fact that during this bird’s lifetime, its long-distance migrations have exceeded the length of the journey from Earth to the Moon.
website: BirdLife International. 2018. Calidris canutus. The IUCN Red List of Threatened Species 2018: e.T22693363A132285482.
View sourcereport, 2018: Wetlands International
website, 2012: Robinson and Clark, The Online Ringing Report: Bird ringing in Britain & Ireland in 2011
View source