The Red Knot, Calidris canutus [Knot in Europe]
is a large member of the Calidris Sandpipers,
second in size to the Great Knot. This species forms enormous flocks when not
breeding. The red knot has one of the longest migrations of any bird. Every
year it travels more than 15,000km from the Arctic to the southern tip of South America.
The bird has a
small head and eyes, a short neck and a slightly tapering black bill. It has
short dark legs. The winter plumage is uniformly pale grey, and is similar
between the sexes. The breeding, plumage is mottled grey on top with a cinnamon
face, throat and breast and light-coloured rear belly. The plumage of females
is similar to that of the male except it is slightly lighter and the eye-line
is less distinct.
The large 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.
On the breeding
grounds, Knots feed on 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.
They breed in the
Tundra and the Arctic Cordillera in the far north of Canada,
Russia and Europe.
North American breeding birds migrate to coastal areas in Europe and South
America, while the Eurasian breeding birds winter in Africa, Asia Australia and
New Zealand.
The Red Knot is territorial. Males arrive in the breeding grounds before
females and begin defending territories.
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.
Both parents
incubate the eggs, the incubation period lasting about 22 days. 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 American
subspecies have become threatened as a result of commercial harvesting of horseshoe
crabs in 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. In 2003, scientists projected that at its current rate of decline
the American subspecies might become extinct as early as 2010. As of April 2011
the subspecies is still extant. Several environmental groups have petitioned the
U.S.
government to list the birds as endangered, but thus far their requests have
not been granted. 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 that the ban would help restore the Red Knot's numbers to
justify the potential disruption to the fishing industry. Instead, a male only
harvest has been permitted in recent years.
This common summer visitor can be seen on any of the following Aves
Birding Tours/Safaris/Adventures: -
Aves Eastern Cape
Birding
Tour/Safari/Adventure.
Aves Western Cape
Birding
Tour/Safari/Adventure.
Aves West Coast Birding Tour/Safari/Adventure.