Slender-billed Curlew
Slender-billed Curlew
The Slender-billed Curlew (Numenius tenuirostris ) is a monotypic species of the family of the Waders. The species is one of the rarest of the Western Palearctic and is threatened by the IUCN as directly with extinction ( critically endangered ) classified. In the 19th century, the Slender-billed Curlew was still regularly in Central Europe, although rarely observed as a migrant and winter visitor. Since the 1980s, however, there are only a few documents. Most come from Hungary, where there were between 1990 and 1999 a total of seven observations of thin-billed curlews.
Description
The Slender-billed Curlew reaches a body length of 36-41 inches and weighs 255-360 grams. The wingspan is 80 to 92 centimeters. He makes it about as big as a Whimbrel, but much slimmer. The plumage coloration reminiscent of a curlew, but the Slender-billed Curlew is usually much brighter and the beak is completely black. The beak is more slender than most curlew species and runs in a fine lace. In breeding plumage especially the heart-shaped spots fall on the flanks. The outer primaries are almost black, contrasting with flying birds strikingly with the white spotted inner wings and the great coverts.
The rump and the rear back are pure white, the tail is dark and white banded. The legs are dark gray. The cries of the Slender-billed Curlew are similar to those of the curlew, but they are a little higher and shorter.
Distribution and population development
The Slender-billed Curlew was originally used in Western Siberia in the moors at the Irtysh and Ob. The only precisely known breeding sites were located approximately 250 km north of Omsk, where Slender-billed Curlews hatched in the years 1914-1924 in the region Tara. The migration routes lead out of this region in the south-west to the Mediterranean, where the birds spend the winter in an area that extends to Morocco. In small numbers they hibernate probably in Iraq, the Persian Gulf and the Arabian Peninsula. Since the 1980s, wintering birds were observed in Morocco only in one place. Were seen there five birds in 1986, four in 1988, three in the years 1989 to 1992, two in 1993 and 1994 and one in 1995. Since 1995 there are no more observations.
It is not known which region Slender-billed Curlews still brooding. Between 1990 and 2008 have been several attempts to locate these breeding areas, but without success. The mid-1990s still existed 50-270 individuals. In May 1998, a young bird was seen in England, is so certain that in 1997 there were still nesting birds. In Ukraine, in July and August 2003 and again seen in August 2004, four birds, where it was highly likely that Slender-billed curlews. A considered reliable sighting there was in March 2005 in Montenegro.
The cause of the sharp decline applies the intense hunting persecution in the resting and wintering areas. Because of their great similarity with other curlews, the risk is very high in thin-billed curlews that they were accidentally shot. Apparently also went most important resting places in steppe areas and wetlands in the Mediterranean lost. Is suspected also that breeding areas were destroyed by conversion to agricultural land. The strong population decline has probably led to a collapse of the social structure.
Habitat and behavior
The Slender-billed Curlew breeds in extensive peat bogs, which are covered with sedges, marsh horsetail, dwarf birch and willow basket. Outside the breeding season, he considers himself a similar way to the curlew on mudflats and salt marshes and freshwater wetlands. It has been observed among other things in saline sagebrush steppe, in Quellerfluren in the fields.
The food consists of insects, molluscs, crustaceans and worms. Due to the very slender beak was concluded that the type smaller prey preferred, and this in a softer substrate studied as the curlew and the Whimbrel. Very little is known about the reproductive biology. On the basis of the few nests found, however, is certain that Slender-billed Curlews breed in shallow ground nests. The nest consists of four eggs. These are grauoliv, ocher or brown and have dark spots and polka dots on.