A globe-trotting shorebird that makes one of the longest migrations on Earth, flying from Arctic breeding grounds to southern wintering sites each year.

Visual Identification

Appearance

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.

Size

Length

23cm to 26cm

Wingspan

45cm to 54cm

Weight

100g to 200g

Colours

Males and females have similar plumage

Primary Colour

Red Grey

Secondary Colour

White

Beak Colour

Black

Leg Colour

Black

Habitat and Distribution

Habitats

Woodland

Garden

Wetland

Coastal

Urban

Farmland

Grassland

Desert

Tundra

Rainforest

Mountain

Savanna

Distribution

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.

Elevation Range

Sea level to 300 meters

Climate zones

Arctic, Temperate, Tropical

Distribution Map

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Resident
Breeding
Non-breeding
Passage
Vagrant

Distribution by Region

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Behaviour and Ecology

Bird Attributes

Tap the icon next to each attribute for more information.

Agility 85
Strength 70
Adaptability 95
Aggressiveness 30
Endurance 98

Diet

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.

Behaviour

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.

Vocalisation

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.

Nesting & Breeding

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.

Lifespan

Typical Lifespan Range 8 - 10 years
Max Recorded Lifespan 27 years [1]
0
7
15
22
29

years

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.

Conservation and Status

Global Conservation Status

Near Threatened [2]

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.

Population Data

Global Population Estimate

891,000 - 979,000 individuals [3]

Global Population Trend

Decreasing[4]

Birdwatching Tips

  • Look for Red Knots on coastal mudflats and sandy beaches during migration seasons.
  • Observe their rapid probing behaviour as they feed in shallow water.
  • In spring, watch for their distinctive rusty-red breeding plumage.
  • Listen for their soft 'knut-knut' call, especially in flight.

Additional Information

Quick Facts

Other names:

Knot, Lesser Knot

Family:

Scolopacidae

Predators

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.

Did You Know?

  1. Red Knots can double their body weight before long migratory flights.
  2. Some Red Knots fly the equivalent of the Earth's circumference in their lifetime.
  3. Their scientific name, Calidris canutus, is linked to King Canute of England, who allegedly tried to command the tides.

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FAQs

Why are red knots so important?

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.

Why are red knots called moon birds?

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.

References

  1. 2

    website: BirdLife International. 2018. Calidris canutus. The IUCN Red List of Threatened Species 2018: e.T22693363A132285482.

    View source
  2. 3 4

    report, 2018: Wetlands International

  3. 1

    website, 2012: Robinson and Clark, The Online Ringing Report: Bird ringing in Britain & Ireland in 2011

    View source