Eskimo Curlew, Numenius borealis

Eskimo Curlews are considered critically endangered and possibly extinct, with no reliable sightings since the 1980s, and none confirmed since the 1960s.

Eskimo Curlews were known to breed in the Arctic tundra of Canada and Alaska. They typically nested on the open ground. They preferred low-lying areas with some vegetation for cover. Their nests were simple scrapes on the ground, lined with grasses, lichens, and feathers. The choice of materials for nest-making was influenced by the availability of suitable vegetation in their breeding habitat.

Females laid 3 to 4 eggs. The exact timing of egg-laying was likely to coincide with the peak of the breeding season in late May to June. The female would then incubate the eggs for about 21 to 23 days until they hatched. During incubation, the male might have assisted in providing protection and food for the female.

Once the eggs hatched, both the male and female would be involved in caring for the chicks. The chicks were precocial, meaning they were relatively mature and mobile shortly after hatching. They would leave the nest within a few hours or days and begin foraging for food themselves. The parents would lead the chicks to suitable foraging areas where they could search for small arthropods, such as beetles, caterpillars, flies, spiders, and other invertebrates found in the tundra vegetation.

Although the chicks were capable of feeding themselves, the adults had to remain vigilant and vocal to ward off potential threats and predators. They were particularly vulnerable to predation from Arctic foxes, owls, falcons, and gulls.

Eskimo Curlews migrated long distances from their Arctic breeding grounds in Canada and Alaska to their wintering areas in South America. According to historical observations, Eskimo Curlews migrated to the grasslands, savannas, and coastal wetlands of countries like Argentina, Brazil, Uruguay, and Paraguay.

Eskimo Curlews were known to be primarily insectivorous during both their breeding and migration periods. In their Arctic breeding grounds, they foraged for insects, larvae, and other invertebrates found in the tundra vegetation and wetlands. During migration and in their wintering areas in South America, they likely continued to feed on a variety of insects, such as grasshoppers, beetles, caterpillars, and other small arthropods.

Additionally, Eskimo Curlews might have also consumed small crustaceans, mollusks, and other aquatic invertebrates found in the coastal wetlands they frequented during migration and winter. They were known for their long, slender bills, which were well-adapted for probing and extracting food from the mud and shallow waters.

There was a significant population of Eskimo Curlews in the past. During the 19th and early 20th centuries, they were one of the most abundant shorebirds in North America, with vast flocks observed during migration.

Commercial hunting, especially during their southward migration, contributed to the drastic decline in their population. They were prized for their rich, flavorful meat, and their large flocks made them an attractive targets. The decline in Eskimo Curlew populations became increasingly apparent during the late 19th and early 20th centuries, as their numbers diminished significantly.

Conservation efforts to protect the Eskimo Curlew began as early as the early 20th century, but it was challenging to implement effective measures due to their extensive migratory range and the lack of precise information about their breeding and wintering grounds. Despite efforts to save the species, the last reliable sighting of an Eskimo Curlew occurred in the 1980s, and since then, the species has been considered critically endangered and possibly extinct.