Eskimo Curlew, Numenius borealis.

Eskimo Curlew, Numenius borealis

The Eskimo curlew is the rarest bird in Canada – if it still exists at all. Like the extinct passenger pigeon, Eskimo curlews once flew over North America in flocks of thousands – their total population was in the millions. Like the passenger pigeon and the great auk, they were unable to withstand the joint pressures of hunting, collecting, and habitat loss, and they are now so rare that their very existence is questioned.

A large shorebird, the Eskimo curlew measures 30–35 cm in length – larger than a blue jay. It has very long, bluish legs and a long, slightly downcurved bill. Its upper parts are mottled golden-brown and its underparts are pale, with light mottling on the breast and neck. It has dark brown eyes with a brown cap and white and brown eye-stripes. Although the curlew is extremely difficult to distinguish from the whimbrel, a closely related shorebird, it can be identified by its more distinctly mottled upper parts, browner colour, smaller body and bill, and its unmarked, buff-coloured wing linings. To make identification more complicated, Eskimo curlews were often associated with whimbrels, nesting in the same area and sometimes following them in flight over long distances. This association was probably advantageous to the curlews, because whimbrels are a wary species, and more likely to notice predators. Since the downfall of the Eskimo curlew, whimbrels have expanded their range to include its former breeding areas. In the past, large flocks of curlews occupied breeding grounds and excluded other species, but now isolated pairs cannot repel the larger, more aggressive whimbrels. Eskimo curlews also often associated with flocks of American golden-plovers, mainly during migration and in South America. It is not known why the plovers did not suffer population reductions similar to those experienced by the curlews, since they occupied similar habitats and were also hunted en route to their breeding grounds.

The Eskimo curlew nested on the tundra in open, grassy areas, where it laid two eggs that were probably incubated by the female. Little else is known about its breeding cycle. The curlew’s original range included a limited area of the western Arctic, from around the treeline north to the coast. It may also have bred on some of the Arctic islands and in Alaska.

The diet of the Eskimo curlew varied over the course of the year. Although they are classified as shorebirds, curlews spent most of their time in upland habitats. In addition to insect larvae and aquatic invertebrates, a major component of the Eskimo curlew’s arctic diet consisted of crowberries, which became known as curlew-berries, and often temporarily tinted their feathers purple. During migration and on their wintering grounds, curlews fed on snails, worms, grasshoppers, other invertebrates, seeds, and berries. Like many other long-distance migrants, Eskimo curlews accumulated huge reserves of body fat before leaving the Arctic in late summer, to give them enough energy to last through their long migration. Nineteenth-century hunters who killed the fat birds in the fall called them "doughbirds", which became a common name for the curlews.

In the fall, curlews migrated in large flocks from the tundra to Labrador and southeastern Canada, from where they began a 4000 km, non-stop journey across the ocean south to their wintering grounds in southern Brazil, Argentina, and Chile. There they wintered in the pampas, or grasslands of southern South America. In the spring, the curlews returned north through the central United States and the Canadian prairies, where they stopped over in fields, often following behind ploughs to pick up worms and insect larvae from the loosened soil. Unfortunately, local hunters and farmers in the 19th century took advantage of this behaviour, using shotguns to kill as many as 28 birds with one shot. Even on their southward migration the curlews were in danger during their short stopover in Labrador: "So abundant were they [in the 1870s] that [Capt. Parsons] often shot a hundred before breakfast during the season, often killing twenty at a single discharge. The fishermen killed them by the thousands...." (Carroll, 1910).

Although the Eskimo curlew was hunted for food, and its skin and eggs were sought by collectors throughout the 19th century, it was not until after the passenger pigeon had been hunted to near-extinction in the 1870s that settlers began to kill the curlew in vast numbers. Eskimo curlews, which migrated in flocks of thousands and could cover 50 acres of ground when they landed, were called "prairie pigeons" – highlighting their similarity to the passenger pigeon, and foreshadowing their similar fate. They were bold – easily lured within firing-range by whistled calls or wooden decoys – and did not fly away when their companions were shot. Most unfortunately of all, Eskimo curlews were good to eat- their dark meat was described as "tender, juicy, and finely flavored", was "considered by epicures the finest eating of any of our birds" and was "far surpassing any of our English game in richness and flavour". While fishermen and farmers shot birds for their own use, others sold wagon-loads of curlews to restaurants in major towns – as many as two million were killed each year. As this continued across all of the curlew’s range, except on its arctic breeding grounds, it is not surprising that its population soon diminished, and by 1890–1900 the birds were already scarce. It has also been suggested that changing climatic conditions in the late 1800s may also have contributed to its decline.

Although the Eskimo curlew is now protected from hunting, it is probably too late. Expansion of agriculture in both North and South America has destroyed many of the grasslands that once formed the curlew’s wintering and stopover grounds.

The Eskimo curlew was listed as endangered in the United States in 1967, and in Canada in 1980 – after many researchers already thought it was extinct. Its fate still hangs in the balance – between 1976 and 1986, less than 40 curlews were observed, and efforts to find more individuals have mostly been unsuccessful. In 1987, a pair of Eskimo curlews may have been seen nesting, and in 1990 one bird was reported in Argentina. Some scientists say there could be up to 50 individuals left, but the species may also be extinct. In any case, their population is so small, so remote and so poorly-studied, that it would be extremely difficult to organize any recovery effort. Sadly, this tiny population is unlikely to recover, and once the few remaining individuals are gone, the Eskimo curlew will vanish forever.