Red knots are a medium-sized shorebird that is named for the rusty red feathers on their breasts during breeding season. But where does their interesting name “knot” come from? There are a few possible explanations.
Their Flocking Behavior
One theory is that “knot” refers to the way red knots tend to flock together in tight groups while foraging and during migration. When seen from a distance, a flock of red knots may look like a knotted mass as the birds constantly land, take off, and swirl together.
In flight, flocks of red knots demonstrate impressive aerobatics as they change direction simultaneously while packed close together. This knot-like flocking behavior might have inspired early observers to start calling the birds “knots.”
Resemblance to Knotted Rope
Another possibility is that the name refers to the red knots’ subtly streaked and speckled plumage, which can resemble twisted knotted rope when seen up close. The intricate patterning on their feathers may have brought to mind knotted fiber rope, leading to the descriptive moniker “knot.”
During the 19th century when many bird species were being named and categorized, visual appearance often played a key role in choosing common names for birds. The knotted rope-like look of red knots feathers could have been a factor in their naming.
Confusion with the Red Knot Sandpiper
There is also a very similar-looking shorebird called the red knot sandpiper. It’s possible that the name “red knot” was originally meant to only refer to that species, but the names became confused over time and interchanged between the two birds.
Red knot sandpipers strongly resemble red knots, especially during breeding season when both species sport reddish feather coloring. Early naturalists may have conflated the two distinct species due to their visual similarities.
Knotted Survival Strategy
An additional idea is that “knot” refers to the impressive long-distance migrations undertaken by red knots. Red knots complete seasonal migrations of well over 9,000 miles between their Arctic breeding grounds and southern wintering habitats.
These extremely lengthy migrations were known and documented even centuries ago amongst naturalists and hunters. Completing such a long and arduous journey was seen as something of a “knotty” problem that the birds somehow managed to solve, or “knot” together successfully. Hence, they became known as red knots.
The Knotted Scales Link
One more theory looks back to the Old English word “cnotta” meaning knot or node. This word was sometimes used to refer to the knotted scales present on some reptiles. As a shorebird, the red knot’s scientific name is Calidris canutus.
It’s possible this scientific name references the Old English “cnotta” meaning knotted scales. The theory suggests that the scientific name inspired the common name “knot” even though red knots obviously lack scaless.
An Enduring Mystery
Unfortunately, there is no firm consensus on the exact origin of why red knots came to be known as “knots.” The colorful theories range from their flocking behavior, feather patterns, confusion with a similar species, tough migrations, or even a possible misapplied reference to knotted scales.
The true circumstances that led to red knots being called knots may be lost to history. But their intriguing name has endured for centuries and continues to prompt curiosity about these amazing globe-trotting shorebirds.
Red Knot Fast Facts
Here are some key facts about the amazing red knot:
- Scientific name: Calidris canutus
- Other common names: Knot, red knot sandpiper
- Length: 9-11 inches
- Wingspan: 20-24 inches
- Weight: 4.4-6.3 ounces
- Lifespan: Up to 15 years
- Diet: Mollusks, crustaceans, insects, plant tubers
- Range: Circumpolar Arctic regions
- Habitat: Coastal wetlands, tidal mudflats, beaches
- Migrations: 9,300+ mile flights between Arctic and southern South America/North America
- Conservation status: Near threatened
Physical Characteristics
Red knots are medium-sized shorebirds measuring 9-11 inches from bill to tail. They have a wingspan of around 20-24 inches and weigh just 4.4-6.3 ounces. Their thin bill is black and around 1-1.5 inches long. During breeding season, red knots sport bold reddish-orange plumage on their face, breast, and belly. For the rest of the year, they are more grayish above and white below.
Their legs and feet are dark gray to black. To withstand cold Arctic conditions, red knots have dense, waterproof plumage and a thick layer of fat. Males and females look identical. Juveniles have a more muted version of the reddish breeding plumage and grayer overall coloration.
Breeding and Nesting
Red knots breed in Arctic regions scattered across northern Canada, Alaska, Greenland, Scandinavia, and Russia. They time their arrival on the breeding grounds to coincide with the thawing of ice and brief surge of insect prey. Red knots nest in dry, open tundra habitats near water.
Their nests consist of shallow scrapes lined with grasses, leaves, and lichens. Males perform aerial displays to attract mates. Once paired, the male will defend the territory while the female lays 3-4 eggs. The eggs are buff colored with brown spotting. Both parents share incubation duties for around 22 days.
The precocial downy chicks are able to leave the nest within a day after hatching. The parents will care for and brood the chicks for up to 3 weeks as they feed and teach them to forage on their own. Once independent, the juvenile birds will start migrating south.
Red Knot Nesting Facts
- Clutch size: 3-4 eggs
- Incubation period: 22 days
- Both parents incubate
- Chicks can leave nest right after hatching
- Chicks independent in 3 weeks
Diet
Red knots are versatile foragers that target a variety of marine invertebrate prey and some plant tubers. On their Arctic breeding grounds, they probe wet tundra for insects, larvae, spiders, crustaceans, and mollusks. They rely heavily on eggs from Lapland longspurs and snow buntings.
While migrating and wintering at temperate and tropical coastal sites, red knots eat marine worms, mollusks, and small crustaceans by probing into sand, mud, or soggy soil with their long bills. Favorite foods include coquina clams, blue mussels, shrimp, amphipods, and crab eggs. They occasionally ingest some plant material like cordgrass roots and seeds.
Red Knot Diet
- Insects
- Spiders
- Crustaceans
- Mollusks
- Marine worms
- Eggs
- Plant tubers
Migration
Red knots are champion ultramarathon migrators, traveling tremendous distances between their Arctic breeding areas and wintering grounds that may be thousands of miles away in Latin America or the Southeast United States. Some individuals log an annual roundtrip of more than 18,000 miles!
Flocks numbering from dozens to thousands of birds make the journey over oceans and continents to follow optimal habitat conditions throughout the year. Their migrations require efficient fat storage and precisely timed energy output. Red knots coordinate stops to rest and refuel at key coastal sites.
Some of the most important shore sites providing food resources for migrating knots include Delaware Bay on the US East Coast, the Yellow Sea in Asia, and Ría Grande in Tierra del Fuego, South America. Threats to these stopover habitats have become a major conservation concern.
Key Red Knot Migration Stops
- Delaware Bay (US East Coast)
- Yellow Sea (Asia)
- Ría Grande (South America)
Threats and Conservation Status
Red knots face an array of threats throughout their range from habitat degradation, overharvesting of food resources, pollution, disturbance, and climate change impacts. They are considered a threatened species in Canada. Overall, red knot numbers have declined substantially over the past few decades.
Conservation efforts are underway in many countries to restore and protect vital coastal stopover habitats. Public education, regulations on hunting, pollution controls, and monitoring programs are also important initiatives aimed at stabilizing red knot populations.
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While still facing threats, focused conservation initiatives have helped stabilize some red knot populations. However, they remain vulnerable and require ongoing habitat protections and monitoring.
Interesting Red Knot Facts
- Red knots ingest and swallow pebbles both to help grind up food in their gizzard and add ballast weight to facilitate long flights.
- These hardy birds can survive body temperatures down to 59°F during frigid Arctic weather.
- Red knots undergo dramatic seasonal plumage changes, molting and regrowing all their flight feathers following migration.
- They often reuse the same wintering and breeding sites year after year, demonstrating strong site fidelity.
- Red knots migrate in huge flocks that fly in tight synchronized formations for efficiency.
- Flocks perform impressive in-flight maneuvers, all changing direction in unison while centimeters apart from each other.
- Red knots stopping in Delaware Bay feed ravenously on protein-rich horseshoe crab eggs to fuel the next nonstop leg of their journey.
- They can double their weight in under 2 weeks during migration stopovers to build sufficient fat stores.
- Some red knots may spend over 20 years completing annual 19,000 mile roundtrip migrations.
Where to See Red Knots
Prime places to catch sight of red knots include:
- Delaware Bay (DE and NJ) – Mid May migration stopover
- San Antonio Oeste (Patagonia, Argentina) – Wintering grounds
- Banc d’Arguin (Mauritania, Africa) – Wintering grounds
- Río Grande (Tierra del Fuego, Chile) – February-April stopover
- Grays Harbor (WA) – Mid May migration stopover
- Cook Inlet (Alaska) – Breeding grounds
Look for red knots probing wet sand or mudflats in coastal areas as well as flying in large swift flocks. A spotting scope can provide excellent views. Prime viewing is during spring and fall migrations as large numbers funnel through key coastal habitats.
Conclusion
The red knot is a remarkable bird perfectly adapted to undertake marathon migrations spanning thousands of miles between its Arctic breeding grounds and southern wintering areas. These tough shorebirds face serious conservation threats, but focused protection efforts are working to safeguard key habitats worldwide. Red knots continue their epic seasonal journeys using innate resilience honed over eons. Their knots of tightly packed flocks are an inspiring sight during the birds’ travels across coasts and continents. Wherever it originally derived, the name “knot” is a fitting moniker for this world traveler.
