MacKay 1892). Its continued failure to recover 

 after hunting in the United States was banned by 

 the Migratory Bird Treaty Act in 1916 must be 

 attributable to some unique characteristic that 

 makes it more vulnerable to environmental condi- 

 tions than other shorebirds with similar migration, 

 breeding, and wintering ranges. That characteris- 

 tic may be a greater concentration of all members 

 of the population at all times, making it more 

 vulnerable to short but critical periods of unfavor- 

 able weather and habitat conditions (Banks 1977). 

 The conversion of native grasslands to cultivated 

 fields in both the main wintering area in southern 

 South America and the principle migration route 

 through the tall grass prairie of the United States, 

 which coincided with the population decline 

 (Cooke 1910, Dement'ev and Gladkov 1969) and 

 has continued to the present is one likely reason 

 for its failure to recover. 



It may be that only the natural grasslands of 

 the southern South American pampas and the tall 

 grass prairies of the United States could produce 

 enough easily available food, in the form of grass- 

 hopper egg pods, to supply the energy for both 

 the curlew's exceptionally long migration flights 

 and the initiation of breeding in the spring. The 

 Arctic tundra presumably provides enough crow- 

 berries and blueberries to support the fall migra- 

 tion, but the South American and North Ameri- 

 can grasslands, whose more productive areas are 

 now largely cultivated, may not provide enough 

 suitable insect life in winter and early spriiig to 

 enable the curlews to travel their long traditional 

 migration routes. 



PRIORITY INDEX 



55 



DESCRIPTION 



Eskimo curlews are medium-sized shorebirds 

 (about 30 cm long), smaller than whimbrels with 

 shorter (about 5 cm), more slender, slightly down- 

 curved bills; uniformly dark (rather than barred) 

 primaries; greenish (rather than gray) legs; more 

 blackish above with unstriped dark crowns. They 

 may be distinguished from very similar little cur- 

 lews [Numenius minutus) which breed in north- 

 east Asia and migrate through western Asia to 

 Austraha, by their generally darker and more 

 buffy coloration with v-shaped black marks, in- 

 stead of streaks, below and darker cinnamon buff 



coloration under wings (Forrand 1977). The two 

 forms are considered races of the same species by 

 Dement'ev and Gladkov (1951) but as two distinct 

 species by the American Ornithologists' Union 

 (1957). 



RANGE 



N. borealis formerly nested in the Arctic 

 tundra of northwestern Mackenzie between the 

 Mackenzie and Coppermine Rivers (MacFarlane 

 1891, Swainson and Richardson 1881). There 

 have been several probable sightings by Canadian 

 Wildlife Service personnel east of the Mackenzie 

 River delta in a general area where nesting is 

 known to have occurred formerly. They probably 

 nested in Alaskan tundra west to the Bering Sea 

 (Nelson 1887, Murdock 1885); they wintered in 

 grasslands of southern South America from 

 southern Brazil and Uruguay, with a few probably 

 north of Buenos Aires, Argentina (Cooke 1910), 

 south to middle-eastern Argentina, chiefly north 

 of the Chubut River; casually to Chile and Tierra 

 del Fuego (Greenway 1958, Barrows 1884, Bent 

 1929, Cooke 1910, Swenk 1926, Sclater and 

 Hudson 1889,Wetmore 1926). 



Fall migration (adults preceeding young), be- 

 ginning in July, was southeasterly from the breed- 

 ing grounds to a feeding and staging area on the 

 coast of southern Labrador (Audubon 1835, 

 Townsend 1907,Coues 1861, Austin 1932, Todd 

 1963); thence via Newfoundland and Nova Scotia 

 (Tufts 1961, Peters and Burleigh 1951) over the 

 Atlantic Ocean directly to eastern South America, 

 and ending on the wintering grounds in early Sep- 

 tember (Sclater and Hudson 1889 , Barrows 1884). 

 Severe storms occassionally forced the birds to 

 land on the north Atlantic coast of the United 

 States (Bent 1929,Forbush 19 12, Sage and Bishop 

 1913, Palmer 1949, Griscom and Snyder 1955), 

 Bermuda, and the eastern islands of the West 

 Indies (Bond 1956). 



There was a much smaller flight down the 

 west side of Hudson Bay with a few individuals 

 reaching points on the Great Lakes and even Cin- 

 cinnati, Ohio, and Cooke Co. Texas (Cooke 1910, 

 Hagar and Anderson 1977). By what route those 

 birds reached the wintering grounds (if they did) 

 is unknown. 



Spring migration began in late February (Bar- 

 rows 1884), heading northwest from the winter- 

 ing area, probably across the Andes in Chile, the 



