International action plan for



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- 8 -

 

 



Threats and limiting factors 

 

* Habitat 



loss 

 

Due to the lack of knowledge concerning the location of the breeding grounds, it is not 



possible to assess the scale of threat posed by their modification/loss. In general the taiga 

has been little modified, the forest-steppe partly cultivated (but with many wetlands 

remaining), and much of the steppe severely modified by intensive agriculture. The 

importance of this factor could thus range from low to high, depending on which habitat 

is used for nesting. 

 

 



Much of the passage route has been greatly modified by man, for example the Aral Sea 

area and the steppe areas of central and eastern Europe. There has also been a general 

loss of wetlands throughout the western Palearctic. The loss of traditional stopover sites 

may have had serious effects on the Slender-billed Curlew, but, as noted above, it can use 

a range of passage habitats and yet has still suffered a much greater decline than other 

waders crossing the same region. 

 

 

Parts of the winter quarters (e.g. the Rharb plain of north-west Morocco) have been 



greatly affected by man, with large-scale drainage of wetlands. In Tunisia also, 

temporary freshwater marshes (e.g. Kairouan) have been seriously damaged by the 

construction of dams for flood control and the provision of water supplies. Elsewhere in 

North Africa, however, other types of wetland have been less affected, such as coastal 

sites and inland sebkhets/chotts (temporary brackish wetlands, e.g. those near 

Constantine in Algeria). The situation is hard to assess while Merja Zerga remains the 

only known current regular wintering site for the species. In the Middle East, the marshes 

of Iraq are potentially a very important wintering site, but are rapidly being destroyed. 

The area of the central (Qurnah) marshes had been reduced by 1991/92 to 67% of its 

1984/85 area, while the area of permanent marshes overall had been reduced to 40% of 

the 1984/85 area (from 1,133,000 ha to 457,000 ha). If drainage plans proceed as at 

present, the marshes will probably be lost in 10–20 years (Maltby 1994). 

 

Importance: 



low-high (breeding areas) 

 

 



 

medium-high (passage and wintering areas) 

 

* Hunting 

 

In the early part of the twentieth century, across much of Europe, hunting of waders took 



place on a large scale (principally for food), with curlews (as the largest waders) being a 

favoured quarry. Significant numbers of Slender-billed Curlew specimens, notably from 

Hungary and Italy, date from this time, the birds often being from markets (Gretton 

1991). Because the Slender-billed Curlew is often tamer than its congeners (Gretton 

1991), it could have suffered very heavily at this time. Indeed there is considerable 

evidence that hunting may have been the key cause of its decline, with habitat loss an 

important secondary factor – though it is hard to imagine habitat loss affecting this one 

species more than any other European wader. The selective threat posed by hunting is 

clear: curlews were the prime wader targets for food, and Slender-billed Curlews 

(according to much evidence) were the tamest curlew. It would be difficult, perhaps 




 

 

 



- 9 -

impossible, to prove absolutely that hunting was the key factor some 60–100 years after 

the main period of decline, but the available evidence points in this direction. 

 

 



At least up to the 1970s there was also strong hunting pressure in parts of North Africa. 

At present the threat is generally less, but between 1962 and 1987 17 Slender-billed 

Curlews are known to have been shot (13 of these in Italy and former Yugoslavia). With 

the world population being so low, this number is highly significant; the loss of even a 

single further bird to hunting is unacceptable. 

 

Importance: 



medium (but historically high) 

 



Breakdown of social behaviour patterns 

 

This is very much a secondary factor, not responsible for the original decline, but likely 



to be important in keeping numbers low following the main decline (i.e. during the last 

30–50 years). Early records often referred to large flocks of the species on migration and 

in winter, and it is possible that the experience of older birds was important in guiding 

such flocks. As Slender-billed Curlew numbers fell, individuals would be more likely to 

join flocks of other species, notably Eurasian Curlew. The chances of Slender-billed 

Curlews meeting each other on the breeding grounds would become increasingly low, as 

was graphically described for the Eskimo Curlew by Bodsworth (1954). Without drastic 

(and probably unfeasible) intervention, there is little that can be done to ameliorate these 

effects. 

 

Importance: 



medium-high (following initial decline) 

 

* Other 



factors 

 

Many other possible causes of the decline have been considered (Gretton 1991), but very 



few are thought plausible. Two factors, affecting parts of Kazakhstan potentially used by 

the species, are highly speculative but warrant a mention, although it is difficult to obtain 

precise information on either. The level of use of agricultural chemicals in the Aral Sea 

area (since the 1950s) has caused widespread concern, and has been held responsible for 

widespread human illness and high levels of child mortality. The lack of water in the area 

would serve to concentrate such chemicals still further, and could contaminate Slender-

billed Curlews via their food, or directly in drinking water. 

 

 



There are (unconfirmed) reports of nesting Slender-billed Curlews from Ust-

Kamenogorsk and Semipalatinsk (Gavrin et al. 1962) in the 1920s and 1930s. The main 

nuclear testing ground of the former U.S.S.R. is just west of Semipalatinsk, and was used 

until very recently. In earlier years atmospheric tests were conducted here, presumably 

causing major contamination. Summer records of the species are also known from the 

Chelyabinsk region (Gavrin et al. 1962), and in recent years very high levels of 

radioactivity have been found in the environment near Chelyabinsk–40 (E. Nowak 

verbally). At present we do not have enough information to assess whether such factors 

could have affected the Slender-billed Curlew, but the possibility cannot be entirely ruled 

out. 


 Importance: 

unknown 


 

Conservation status and recent conservation measures 

 

* International 





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