Red Knot
Near ThreatenedCalidris canutus
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
This map gives you a rough idea of where you might spot a Red Knot. The coloured areas show countries where these birds have been seen.
A few things to keep in mind:
- Birds might not be everywhere in the coloured areas, for example, they may be present around the coast of that country
- Where birds live can change with seasons and available food
- This map is quite simple - it doesn't show exact locations
We're working on making our maps even better! Soon, we hope to show you:
- More detailed maps for bigger countries, including state and region
- How birds move around during different seasons
Distribution by Region
Behaviour and Ecology
Bird Attributes
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Share your thoughtsBird Attributes Explained
Our bird attributes system rates various aspects of a bird's capabilities on a scale of 0-100, based on data from field observations, scientific studies, and expert knowledge.
Attribute Categories:
- Agility: Manoeuvrability, speed, and grace in flight or movement.
- Strength: Physical power, often correlating with size and hunting abilities.
- Adaptability: Ability to thrive in various environments or changing conditions.
- Aggressiveness: Territorial behaviour and assertiveness, particularly during breeding seasons.
- Endurance: Stamina, often seen in migration patterns or foraging behaviours.
Understanding the Ratings:
- 0-20: Very Low
- 21-40: Low
- 41-60: Average
- 61-80: High
- 81-100: Very High
Remember, these attributes are relative to other bird species and don't necessarily indicate superiority.
Hover over the icon next to each attribute for more information.
Tap the icon next to each attribute for more information.
Agility
Reflects the bird's manoeuvrability, speed, and grace in flight or movement.
The Red Knot demonstrates remarkable agility, particularly during its long-distance migrations and in its ability to navigate diverse coastal environments. Its swift flight and nimble foraging behaviour in shallow waters showcase its high level of agility.
Strength
Indicates the bird's physical power, often correlating with size and hunting abilities.
Whilst not exceptionally strong for its size, the Red Knot possesses sufficient strength to undertake gruelling long-distance migrations, sometimes doubling its body weight beforehand. Its ability to probe into sand and mud for food also indicates a decent level of strength.
Adaptability
Represents the bird's ability to thrive in various environments or changing conditions.
Red Knots exhibit extraordinary adaptability, thriving in environments ranging from Arctic tundra to tropical coastlines. Their ability to alter their plumage seasonally and adjust their diet based on location demonstrates remarkable adaptive capabilities.
Aggressiveness
Measures the bird's territorial behaviour and assertiveness, particularly during breeding seasons.
Red Knots are generally non-aggressive birds, often seen feeding in large, peaceful flocks. They do not typically engage in territorial disputes outside of the breeding season, and even then, aggression is limited to aerial displays rather than physical confrontations.
Endurance
Reflects the bird's stamina, often seen in migration patterns or foraging behaviours.
The Red Knot's endurance is truly exceptional. Its ability to fly up to 30,000 km (around 18,600 miles) annually, with some individuals covering distances equivalent to the Earth's circumference in their lifetime, places it among the most enduring of bird species.
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
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
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.
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:
ScolopacidaePredators
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?
- Red Knots can double their body weight before long migratory flights.
- Some Red Knots fly the equivalent of the Earth's circumference in their lifetime.
- Their scientific name, Calidris canutus, is linked to King Canute of England, who allegedly tried to command the tides.
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Community Experience
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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
- 2
website: BirdLife International. 2018. Calidris canutus. The IUCN Red List of Threatened Species 2018: e.T22693363A132285482.
View source - 3 4
report, 2018: Wetlands International
- 1
website, 2012: Robinson and Clark, The Online Ringing Report: Bird ringing in Britain & Ireland in 2011
View source