Translate

Saturday 5 September 2015

Red knot (Calidris canutus) (Linnaeus, 1758) Διπλονεραλλίδι, Κοκκινοσκαλίδρα, Χοντροσκαλίδρα - Cyprus


The red knot (Calidris canutus) (just knot in 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.
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 the 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.[18] 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, andrufa 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.From Wikipedia, the free encyclopedia

.Photos and video Akrotiri 5/9/2015  by George Konstantinou





No comments:

Post a Comment