The red knot (Calidris canutus) (just knot in English-speaking Europe) is a medium-sized shorebird which breeds in tundra and the Arctic Cordillera in the far north of Canada, Europe, and Russia. It is a large member of the Calidris sandpipers, second only to the great knot. Six subspecies are recognised.
Their diet varies according to season; arthropods and larvae are the preferred food items at the breeding grounds, while various hard-shelled molluscs are consumed at other feeding sites at other times. North American breeders migrate to coastal areas in Europe and South America, while the Eurasian populations winter in Africa, Papua New Guinea, Australia, and New Zealand. This species forms enormous flocks when not breeding.
|Calidris canutus rufa, breeding plumage|
|Distribution and migration routes of the six subspecies of the red knot|
The red knot was first described by Linnaeus in the landmark 1758 tenth edition of his Systema Naturae as Tringa canutus. One theory is that it gets its name and species epithet from King Cnut; the name would refer to the knot's foraging along the tide line and the story of Cnut and the tide. There appears to be no historical foundation for this etymology. Another etymology is that the name is onomatopoeic, based on the bird's grunting call note.
Population relatedness and divergence. The diversification events may be associated with the Wisconsinan (Weichselian) glaciation 18,000 to 22,000 years ago; the opening of the ice-free corridor in North America 12,000 to 14,000 years ago; and the Holocene climatic optimum 7,000 to 9,000 years ago.
The red knot and the great knot were originally the only two species placed in the genus Calidris, but many other species of sandpiper were subsequently added. A 2004 study found that the genus was polyphyletic and that the closest relative of the two knot species is the surfbird (currently Aphriza virgata).
Studies based on mitochondrial sequence divergence and models of paleoclimatic changes during the glacial cycles suggest that canutus is the most basal population, separating about 20,000 years ago (95% confidence interval: 60,000–4,000 years ago) with two distinct lineages of the American and Siberian breeders emerging about 12,000 years ago (with a 95% confidence interval: 45,000–3,500 years ago).
In the breeding season, the red knot has a circumpolar distribution in the high Arctic, then migrates to coasts around the world from 50° N to 58° S. The red knot has one of the longest migrations of any bird. Every year it travels more than 9,000 mi (14,000 km) from the Arctic to the southern tip of South America. The exact migration routes and wintering grounds of individual subspecies are still somewhat uncertain. The nominate race C. c. canutus breeds in the Taymyr Peninsula and possibly Yakutia and migrates to Western Europe and then down to western and southern Africa. C. c. rogersi breeds in the Chukchi Peninsula in eastern Siberia, and winters in eastern Australia and New Zealand. Small and declining numbers of rogersi (but possibly of the later described piersmai) winter in the mudflats in the Gulf of Mannar and on the eastern coast of India. The recently split race C. c. piersmai breeds in the New Siberian Islands and winters in north-western Australia. C. c. roselaari breeds in Wrangel Island in Siberia and north-western Alaska, and it apparently winters in Florida, Panama and Venezuela. C. c. rufa breeds in the Canadian low Arctic, and winters South America, and C. c. islandica breeds in the Canadian high Arctic as well as Greenland, and winters in Western Europe.
Birds wintering in west Africa were found to restrict their daily foraging to a range of just 2–16 km2 (0.77–6.18 sq mi) of intertidal area and roosted a single site for several months. In temperate regions such as the Wadden Sea they have been found to change roost sites each week and their feeding range may be as much as 800 km2 (310 sq mi) during the course of a week.
B95, also known as Moonbird, is a noted individual of the subspecies C. c. rufa. A male, he has become famous amongst conservationists for his extreme longevity — he was aged at least 20 as of his last sighting in May 2014.
An adult red knot is the second largest Calidris sandpiper, measuring 23–26 cm (9.1–10.2 in) long with a 47–53 cm (19–21 in) wingspan. The body shape is typical for the genus, with a small head and eyes, a short neck and a slightly tapering bill that is no longer than its head. It has short dark legs and a medium thin dark bill. The winter, or basic, plumage becomes uniformly pale grey, and is similar between the sexes. The alternate, or breeding, plumage is mottled grey on top with a cinnamon face, throat and breast and light-coloured rear belly. The alternate plumage of females is similar to that of the male except it is slightly lighter and the eye-line is less distinct. Canutus, islandica and piersmai are the "darker" subspecies. Subspecies rogersi has a lighter belly than either roselaari or piersmai, and rufa is the lightest in overall plumage. The transition from alternate to basic plumages begins at the breeding site but is most pronounced during the southwards migration. The molt to alternate plumage begins just prior to the northwards migration to the breeding grounds, but is mostly during the migration period.
The large size, white wing bar and grey rump and tail make it easy to identify in flight. When feeding the short dark green legs give it a characteristic 'low-slung' appearance. When foraging singly, they rarely call, but when flying in a flock they make a low monosyllabic knutt and when migrating they utter a disyllabic knuup-knuup. They breed in the moist tundra during June to August. The display song of the male is a fluty poor-me. The display includes circling high with quivering wing beats and tumbling to the ground with the wings held upward. Both sexes incubate the eggs, but the female leaves parental care to the male once the eggs have hatched.
Juvenile birds have distinctive submarginal lines and brown coverts during the first year. In the breeding season the males can be separated with difficulty (<80% accuracy in comparison to molecular methods) based on the more even shade of the red underparts that extend towards the rear of the belly.
The weight varies with subspecies, but ranges between 100 and 200 g (3.5 and 7.1 oz). Red knots can double their weight prior to migration. Like many migratory birds they also reduce the size of their digestive organs prior to migration. The extent of the atrophy is not as pronounced as species like the bar-tailed godwit, probably because there are more opportunities to feed during migration for the red knot. Red knots are also able to change the size of their digestive organs seasonally. The size of the gizzard increases in thickness when feeding on harder foods on the wintering ground and decreases in size while feeding on softer foods in the breeding grounds. These changes can be very rapid, occurring in as little as six days.
On the breeding grounds, knots eat mostly spiders, arthropods, and larvae obtained by surface pecking, and on the wintering and migratory grounds they eat a variety of hard-shelled prey such as bivalves, gastropods and small crabs that are ingested whole and crushed by a muscular stomach.
While feeding in mudflats during the winter and migration red knots are tactile feeders, probing for unseen prey in the mud. Their feeding techniques include the use of shallow probes into the mud while pacing along the shore. When the tide is ebbing, they tend to peck at the surface and in soft mud they may probe and plough forward with the bill inserted to about 1 cm (0.39 in) in depth. The bivalved mollusc Macoma is their preferred prey on European coasts, swallowing them whole and breaking them up in their gizzard. In Delaware Bay, they feed in large numbers on the eggs of horseshoe crabs which spawn just as the birds arrive in mid-summer. They are able to detect molluscs buried under wet sand from changes in the pressure of water that they sense using Herbst corpuscles in their bill. Unlike many tactile feeders their visual field is not panoramic (allowing for an almost 360 degree field of view), as during the short breeding season they switch to being visual hunters of mobile, unconcealed prey, which are obtained by pecking. Pecking is also used to obtain some surface foods in the wintering and migratory feeding grounds, such as the eggs of horseshoe crabs.
The red knot is territorial and seasonally monogamous; it is unknown if pairs remain together from season to season. Males and females breeding in Russia have been shown to exhibit site fidelity towards their breeding locales from year to year, but there is no evidence as to whether they exhibit territorial fidelity. Males arrive before females after migration and begin defending territories. As soon as males arrive, they begin displaying, and aggressively defending their territory from other males.
The red knot nests on the ground, near water, and usually inland. The nest is a shallow scrape lined with leaves, lichens and moss. Males construct three to five nest scrapes in their territories prior to the arrival of the females. The female lays three or more usually four eggs, apparently laid over the course of six days. The eggs measure 43 mm × 30 mm (1.7 in × 1.2 in) in size and are ground coloured, light olive to deep olive buff, with a slight gloss. Both parents incubate the eggs, sharing the duties equally. The off duty parent forages in flocks with others of the same species. The incubation period lasting around 22 days. At early stages of incubation the adults are easily flushed from the nest by the presence of humans near the nest, and may not return for several hours after being flushed. However, in later stages of incubation they will stay fast on the eggs. Hatching of the clutch is usually synchronised. The chicks are precocial at hatching, covered in downy cryptic feathers. The chicks and the parents move away from the nest within a day of hatching and begin foraging with their parents. The female leaves before the young fledge while the males stay on. After the young have fledged, the male begins his migration south and the young make their first migration on their own.
The red knot has an extensive range, estimated at 100,000–1,000,000 km2 (39,000–386,000 sq mi), and a large population of about 1.1 million individuals. The species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations), and is therefore evaluated as Least Concern. However many local declines have been noted such as the dredging of intertidal flats for edible cockles (Cerastoderma edule) which led to reductions in the wintering of islandica in the Dutch Wadden Sea. The quality of food at migratory stopover sites is a critical factor in their migration strategy.
This is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. This commits signatories to regulate the taking of listed species or their eggs, to establish protected areas to conserve habitats for the listed species, to regulate hunting and to monitor the populations of the birds concerned.
Towards the end of the 19th century, large numbers of red knot were shot for food as they migrated through North America. It is hypothesized that more recently, the birds have become threatened as a result of commercial harvesting of horseshoe crabs in the Delaware Bay which began in the early 1990s. Delaware Bay is a critical stopover point during spring migration; the birds refuel by eating the eggs laid by these crabs (with little else to eat in the Delaware Bay). If horseshoe crab abundance in the Bay is reduced there may be fewer eggs to feed on which could negatively affect knot survival.
In 2003, scientists projected that at its current rate of decline the American subspecies, rufa, might become extinct as early as 2010, but as of April 2011 the subspecies is still extant. In New Jersey, state and local agencies are taking steps to protect these birds by limiting horseshoe crab harvesting and restricting beach access. In Delaware, a two-year ban on the harvesting of horseshoe crabs was enacted but struck down by a judge who cited insufficient evidence to justify the potential disruption to the fishing industry but a male-only harvest has been in place in recent years.
Late in the fall of 2014, the red knot rufa was listed as a federally threatened species under the United States Endangered Species Act – the second most critical status that can be awarded to a subspecies. This followed a decade of intensive petitioning by environmental groups and a lawsuit against the Department of the Interior for alleged negligence in the protection of endangered species through failure to evaluate and list them. The reasons for the red knot rufa's listing were varied; habitat degradation, loss of key food supplies, and threats posed by climate change and sea level rise were all listed as factors that were considered when the red knot rufa was listed.
T. roftro laevi, pedibus cinerascentibus, remigibus primoribus ferratis.
The Akimiski Island Migratory Bird Sanctuary is a migratory bird sanctuary in Qikiqtaaluk, Nunavut, Canada. It is located on Akimiski Island within James Bay. The sanctuary, established by the Canadian government on 1 January 1941, has federal conservation status. Taking up the eastern two-thirds of the island, it is 3,367 km2 (1,300 sq mi) in overall size, including a 1,664 km2 (642 sq mi) marine area. It includes marine, intertidal, and subtidal components and is rated Category IV by the International Union for Conservation of Nature.The coastal waters and wetlands are important feeding grounds for several varieties of migratory waterfowl and shorebirds. These include Atlantic brant, Canada goose, Caspian tern, Hudsonian godwit, lesser snow goose, red knot, and semipalmated plover.Among mammalians, ringed seals, polar bears, and beluga whales can be found in the area.Atlantic horseshoe crab
The Atlantic horseshoe crab (Limulus polyphemus), also known as the American horseshoe crab, is a species of marine and brackish chelicerate arthropod. Despite their name, horseshoe crabs are more closely related to spiders, ticks, and scorpions than to crabs. This species is found in the Gulf of Mexico and along the Atlantic coast of North America. A main area of annual migration is Delaware Bay.Their eggs were eaten by Native Americans, but today Atlantic horseshoe crabs are caught for use as fishing bait, in biomedicine (especially for Limulus amebocyte lysate) and science. They play a major role in the local ecosystems, with their eggs providing an important food source for shorebirds, and the juveniles and adults being eaten by sea turtles.The other three extant (living) species in the family Limulidae are also called horseshoe crabs, but they are restricted to Asia.B95 (bird)
B95 (born c.1993), nicknamed Moonbird, is a red knot celebrated for its longevity as the oldest known member of its species.The bird, a male of the Calidris canutus rufa subspecies of the red knot (a species of shorebird in the sandpiper family), was banded in Río Grande, Tierra del Fuego, Argentina in February 1995 by Patricia González, an Argentine biologist. It has been resighted many times since then, most recently during May 2014 by González in the Canadian Arctic. It also has been recaptured at least three times—the last time in 2007 (aged approximately 14) when it was found to be "as fit as a three-year-old". It is not known how long red knots typically live.Bahía Lomas
Bahia Lomas (or Lomas Bay) is a bay in the eastern mouth of the Strait of Magellan in Southern Chile, on the north coast of the Isla Grande de Tierra del Fuego. The area is a large tidal plain, with a tidal variation up to 7 km. The wetlands of the bay are important sites for the red knot, the Hudsonian godwit and other shorebirds.
The wetlands are a Ramsar site of international importance and an Important Bird Area.Benfleet and Southend Marshes
Benfleet and Southend Marshes is an 8.1-square-mile (21 km2) Site of Special Scientific Interest (SSSI) in Essex. It consists of mudflats, salt marshes, scrub and wild grassland, and includes the Southend-on-Sea foreshore. It has been so recognised for its biological (including ecological) value, rather than geological. A definition five percent larger forms the Benfleet and Southend Marshes Ramsar site and Special Protection Area. In the centre-west, more than ten percent of the Site is the Leigh National Nature Reserve (NNR), which has been appraised in detail in A Nature Conservation Review as a site of national importance. The SSSI and NNR include the eastern half of Two Tree Island, in Leigh on Sea which is managed by the Essex Wildlife Trust. A narrow majority of the Site is the Southend on Sea Foreshore Local Nature Reserve.The marshes and mudflats have internationally important numbers of wildfowl and wading birds, including the dark-bellied brent goose, grey plover, redshank and red knot. Scarce invertebrates, such as the white-letter hairstreak and marbled white butterfly, have adapted to specific habitats in the marshes.Bird Islands Conservation Park
Bird Islands Conservation Park is a 3.69-square-kilometre (1.42 sq mi) protected area in eastern Spencer Gulf, South Australia. It is located at Warburto Point on Yorke Peninsula, about 10 km (6.2 mi) south of the town of Wallaroo. In 1991, land additions were made to the park to include the intertidal zone of both islands. In 1999, a larger, mainland section was added to support mangroves, samphire and coastal fringe vegetation.Calidris
Calidris is a genus of Arctic-breeding, strongly migratory wading birds in the family Scolopacidae. The genus name is from Ancient Greek kalidris or skalidris, a term used by Aristotle for some grey-coloured waterside birds.These birds form huge mixed flocks on coasts and estuaries in winter. They are the typical "sandpipers", small to medium-sized, long-winged and relatively short-billed.
Their bills have sensitive tips which contain numerous corpuscles of Herbst. This enables the birds to locate buried prey items, which they typically seek with restless running and probing.Field guide
A field guide is a book designed to help the reader identify wildlife (plants or animals) or other objects of natural occurrence (e.g. minerals). It is generally designed to be brought into the 'field' or local area where such objects exist to help distinguish between similar objects. Field guides are often designed to help users distinguish animals and plants that may be similar in appearance but are not necessarily closely related.
It will typically include a description of the objects covered, together with paintings or photographs and an index. More serious and scientific field identification books, including those intended for students, will probably include identification keys to assist with identification, but the publicly accessible field guide is more often a browsable picture guide organized by family, colour, shape, location or other descriptors.Grays Harbor National Wildlife Refuge
Grays Harbor National Wildlife Refuge is located within Grays Harbor, at the mouth of the Chehalis River, which makes up the second largest watershed in Washington. It is one of four major staging areas for migrating shorebirds in the Pacific Flyway. Up to one million shorebirds gather here in spring and fall to feed and rest.Grays Harbor is designated as a Western Hemisphere Shorebird Reserve Network Site, recognizing this internationally significant shorebird habitat. Although the refuge occupies only two percent of the intertidal habitat of Grays Harbor, it hosts up to 50 percent of the shorebirds that stage in the estuary. As many as 24 species of shorebirds use Grays Harbor National Wildlife Refuge, with the most abundant species being western sandpiper and dunlin. Semipalmated plover, least sandpiper, red knot, and black-bellied plover are also common during migration. The refuge is also used by peregrine falcon, bald eagle, northern harrier, Caspian tern, great blue heron, songbirds, and a variety of waterfowl.The accessible boardwalk offers a means to develop and implement interpretation and education programs for the more than one million travelers that pass by each year on their way through the gateway to the Olympic Peninsula.Great knot
The great knot (Calidris tenuirostris) is a small wader. It is the largest of the calidrid species. The genus name is from Ancient Greek kalidris or skalidris, a term used by Aristotle for some grey-coloured waterside birds. The specific tenuirostris is from Latin tenuis "slender" and rostrum "bill".Harrison J. Hunt
Harrison J. Hunt was surgeon on the Crocker Land Expedition to the Arctic in 1913–1917, and the first to return to civilization with news of his fellow explorers, who had been trapped in the ice for four years. Hunt escaped after a grueling four-month dog-sled journey accompanied by six Inuit He wrote about the experience in the book North to the Horizon: Arctic Doctor and Hunter, 1913–1917 (Camden, Me: 1930).
Born in Bangor, Maine, Hunt was a graduate of Bowdoin College (class of 1902) and the Bowdoin Medical College (class of 1905). He spent his post-Arctic career working at the Eastern Maine Hospital in Bangor, and was appointed Medical Examiner of Penobscot County, Maine, in 1925.Hunt is credited with finding the major biological specimens returned by the Crocker expedition, the eggs of the red knot, which established its migration pattern between Europe and northern Greenland.Horseshoe crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae, suborder Xiphosurida, and order Xiphosura. Their popular name is actually a misnomer, for they are not true crabs.
Horseshoe crabs live primarily in and around shallow coastal waters on soft sandy or muddy bottoms. They tend to spawn in the intertidal zone at spring high tides. They are commonly eaten in Asia, and used as fishing bait, in fertilizer and in science (especially Limulus amebocyte lysate). In recent years, population declines have occurred as a consequence of coastal habitat destruction and overharvesting. Tetrodotoxin may be present in Carcinoscorpius rotundicauda.Because of their origin 450 million years ago, horseshoe crabs are considered living fossils. A 2019 molecular analysis places them as the sister group of Ricinulei within Arachnida.Kasongo Munganga
Professor Constantin Kasongo Munganga is a politician and monetarist from the Democratic Republic of Congo. He holds a Ph.D. in economics. In 2011, he was elected MP for the constituency of Katanda Territory, in the Kasai-Oriental province. He is the former Chief Executive Officer of the Center for Expertise, Evaluation, and Certification of Precious and Semi-Precious Mineral Substances, CEEC in short. Television audiences nicknamed him "The Man With The Red Knot" because of his appearance on media. Since 1975, he has taught at the Institut Supérieur de Commerce of Kinshasa.Lough Foyle
Lough Foyle, sometimes Loch Foyle (Irish: Loch Feabhail, meaning "Feabhal's loch" or "loch of the lip"), is the estuary of the River Foyle, on the north coast of Ireland. It lies between County Londonderry in Northern Ireland and County Donegal in the Republic of Ireland. Sovereignty over these waters has been in dispute since the Partition of Ireland.Manawatu Estuary
The Manawatu Estuary is an estuary at the mouth of the Manawatu River, near Foxton in the lower North Island of New Zealand. It is a wetland of international significance as one of the few Ramsar sites in New Zealand.
At approximately 250 hectares (620 acres), the Manawatu Estuary is the largest estuary in the lower North Island.A total of 93 different bird species have been identified at the estuary. In 2005 the estuary attained Ramsar status.During spring migratory birds arrive for the summer at the estuary, including the bar-tailed godwit, red knot, Pacific golden plover, Japanese snipe, wandering tattler and whimbrel.Montrose Basin
The Montrose Basin is part of the estuary of the South Esk forming a tidal basin near to the town of Montrose, Angus, on the east coast of Scotland.
The nature reserve in this embayment is internationally important for pink-footed geese, red knot and common redshank and is nationally important for common shelduck, wigeon and common eider ducks. It is also popular with mute swans, oystercatchers and northern lapwings as well as smaller birds. Breeding birds are preyed on by peregrine falcons and sparrowhawks. The visitor centre, run by the Scottish Wildlife Trust, is accessible from the A92 road.
The swans give the Basin its old, more poetic name, the "Sea of Swans".The Montrose Basin Heritage Society was formed in 1999 to bring together information about the basin, including its history and archaeology.
The Basin has been exploited for its seafood. At one time Montrose was Scotland's second largest exporter of salmon; and mussel cultivation gave it the largest mussel beds in the country during the 19th and early 20th centuries. Eels have also been an important catch.
The Montrose Basin was hit by a tsunami in 6100 BC, generated by the massive underwater Storegga Slide, in Norway. It was 70 feet (21 m) high when it hit the basin, with the waters travelling inland as far as Forfar.Scouts Australia
Scouts Australia, officially The Scout Association of Australia, is the largest Scouting organisation in Australia. It is a member organisation of the World Organization of the Scout Movement. It operates personal development programs for children and young adults from 5 to 25 years of age in Australia and Australian territories. Scouts Australia was formed in 1958 and was incorporated in 1967. Scouts Australia's programs were opened to girls after 1971.The current stated purpose of Scouts Australia is to "contribute to the development of young people in achieving their full physical, intellectual, emotional, social and spiritual potentials as individuals, as responsible citizens and as members of their local, national and international communities".Despite opening participation to girls and ever younger children and Australia having a high population growth rate, well above the world average, participation in the organisation's programs declined in the late 20th century and early 21st century. According to a 2014 media article: "Scouts Australia is hoping [to] arrest a steady decline in membership. In 1979 the organisation had 114,500 youth members, today there are 52,000." According to its own Annual Reports participation decreased from 84,502 in 2,126 Groups in 2001 to 63,200 in 1,836 Groups in 2005, and in 2012 there were 49,181 youth, 2,587 young adult Rovers and 14,113 adult leaders and support roles in 1,486 groups. This means the organisation has an exceptionally high number of adults compared to its number of youth participants with a ratio of more than 1 adult for every 3 youths.Stint
A stint is one of several very small waders in the paraphyletic "Calidris" assemblage – often separated in Erolia – which in North America are known as peeps. They are scolopacid waders much similar in ecomorphology to their distant relatives, the charadriid plovers.
Some of these birds are difficult to identify because of the similarity between species, and various breeding, non-breeding, juvenile, and moulting plumages. In addition, some plovers are also similarly patterned, especially in winter. With a few exceptions, stints usually have a fairly stereotypical color pattern, being brownish above and lighter – usually white – on much of the underside. They often have a lighter supercilium above brownish cheeks.Vincent Kartheiser
Vincent Paul Kartheiser (born May 5, 1979) is an American actor. He played Connor on The WB television series Angel and Pete Campbell on the AMC television series Mad Men, for which he received six Screen Actors Guild Award nominations for Outstanding Performance by an Ensemble in a Drama Series and won twice along with the cast.