Considérations sur les causes de la disparition du courlis à bec grêle Numenius tenuirostris

The decline of the Slender-billed Curlew has mainly been contributed to habitat loss and excessive hunting, especially on migration stop-over areas but also in parts of its wintering range. Due to insufficient knowledge of the breeding grounds, little is known of the extent of their contribution to the problem. According to recent litterature the species nested in the transition area of southern taiga and forest-steppe of western Siberia. Recent surveys reveal no records, even of observations, in this area. It has been suggested in the litterature that the specie's breeding haunts were to be found in the steppe and near-steppe areas of Europe and Asia. Zarudny repeatedly reported steppe breeding but his records were judged unacceptable by some authors and so the correctness of his observations needs to be questioned. There is however little scientific evidence for refuting Zarundy's statements. Moreover it maybe no coincidence that the last observations of flocks in the wintering quarters of North-west Africa (1953-1964) coincide with the disappearance of huge areas of steppe in Kazakhstan. Between 1953 and 1963 some 600,000 km2 of virgin steppe, an area as large as the present territory of Ukraine, were converted to meadow and arable land. There are good reasons for thinking that the taiga/forest-steppe zone of western Siberia was not the unique breeding ground it was purported to be. If, as is likely, it would be helpful to locate remaining breeding sites, it may well be useful conducting surveys in the northern Aralo-Caspian steppes as the original habitat has been less affected. Other typical steppe species also suffered from large reductions in the extent of their breeding habitat, there are good reasons for thinking that the Slender-billed Curlew suffered likewise. Some of these species have adapted, more or less, to the new conditions; but some have not, an example being the Sociable Plover Chettusia gregaria which now breeds almost exclusively in steppe sanctuaries in Kazakhstan.