The plight of the Eskimo Curlew, the smallest and most gregarious of the 4 species of Numenius curlews that occur in the Western Hemisphere, has commanded the attention of ornithologists and natural historians for more than a century. Populations of few New World species have suffered such a rapid demise. During the latter half of the nineteenth century, the curlew's population plummeted from at least hundreds of thousands of birds to so few that sightings were considered rare. As this millennium closes, occasional reports of the species renew hope that a small, but viable, population exists and that human intervention may help rescue the species from its precarious existence.
The Eskimo Curlew is known to have nested in a relatively small portion of treeless tundra in the Northwest Territories, Canada, but historical accounts of its numbers point to a more extensive breeding range. After nesting, Eskimo Curlews assembled in huge flocks during late August and early September, primarily along the coast of Labrador, where they fed voraciously, particularly on berries. The berries were converted to fat to fuel a nonstop migration across the western Atlantic Ocean to South America and then farther south to the Pampas and likely to Patagonia. The curlew spent the nonbreeding season there, more than 15,000 kilometers away from its known breeding grounds. Northward migration began in February, and by March individuals had traversed the South American continent, crossed the Gulf of Mexico, and settled onto prairies of the southern Great Plains. These curlews then gradually drifted north, attracted in particular to burned and disturbed portions of the prairie, where they fed on an abundant supply of insects. From there they crossed the Prairie Provinces of Canada in what was probably a nonstop flight that brought them once again to their breeding grounds by late May.
Humans' assault on the species, both direct and indirect, began in the 1850s and, by the end of the nineteenth century, had almost eradicated it. Speculation about causes of the near extinction of the Eskimo Curlew is abundant; indeed, much of it has become dogma. Excessive hunting was clearly a major factor, especially along spring migratory pathways in North America, but the concurrent conversion of prairies to agriculture, suppression of wildfires, and extinction of a principal food source (the Rocky Mountain grasshopper [Melanoplus spretus]) also contributed strongly to this bird's precipitous decline. Similar events occurred slightly later in the Pampas of South America and clearly impeded any recovery of the population. The failure of this population to recover, however, may ultimately relate to characteristics of the bird itself. The Eskimo Curlew's life history traits were conservative, it was highly social, and it relied on specific habitats during restricted periods. The curlew population was likely reduced below its socially sustainable level, just like the Passenger Pigeon (Ectopistes migratorius), which was at the same time racing to extinction. The few Eskimo Curlews that survived into the twentieth century may have adjusted to the wholesale human-caused remake of their landscapes, but they no longer constituted a population sufficient to sustain the recruitment level needed for recovery.
The future of the Eskimo Curlew is at best tenuous. Management options, aside from public education and captive breeding experiments with surrogate species, will remain paper exercises until any remaining individuals are discovered. Should individuals be found, conservation administrators will be faced with difficult decisions. Do they take a conservative approach and study the birds to resolve some of the unknowns about their biology, or rapidly initiate a program centered around captive propagation and eventual release into the wild? Coordinated efforts since the mid-1980s to locate birds have failed, but isolated unconfirmed sightings continue to surface and drive efforts to identify areas and habitats still used by the species.