Eskimo curlew(Numenius borealis) residence description: chapter 1

Species information

Common Name – Eskimo Curlew

Scientific Name – Numenius borealis

Current COSEWIC Status & Year of Designation – Endangered (1978, 1999)

Occurrence in Canada – In Canada, the Eskimo Curlew is only known to have bred in the Northwest Territories and Nunavut, but may have also bred in the Yukon Territory1 (Figure 1). The birds have also been recorded in Newfoundland/Labrador, Nova Scotia, New Brunswick, Prince Edward Island, Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and possibly British Columbia during spring and fall migration.

Rationale for Designation – Enormous decline from 1870s to 1980s; occasional possible sightings with the most recent occurring in the mid-1990s1.

Figure 1. Known and potential historic breeding areas of Eskimo Curlew

Figure 1. Known and potential historic breeding areas of Eskimo Curlew

1) The Nest

Physical Appearance and Context

Any place used as a nest by Eskimo Curlews is considered a residence. Nesting has been verified for only two sites in the Northwest Territories and Nunavut: the base of Bathurst Peninsula in Anderson River area, and the region of Amundsen Gulf/ Coronation Gulf/ Coppermine River. The birds also likely bred in the ‘Barren Grounds’ throughout much of the Northwest Territories, possibly in the Yukon and Alaska, and perhaps into the Chutchi Peninsula, Russia2,3,4. No evidence of nesting has been verified for 136 years5.

As in most other shorebirds, nests were merely a scrape (bowl-shaped depression) in the ground1. Clutch size was normally four eggs, young presumably precocial (mobile within hours of hatching), similar to other North American shorebirds. The birds were presumably monogamous, as in other Numeniini, with incubation shared by both sexes2,3. As in other northern shorebirds, renesting was probably uncommon, and only one brood was raised per season. Age of first breeding is unknown but likely delayed, possibly to three years, as in Whimbrel2,6.

Known breeding habitat consisted of upland tundra, the treeless dwarf shrub, graminoid tundra complex of the Northwest Territories and Nunavut, and grassy meadow habitat (polargrass, arctic bluegrass, birch, sedge, cottongrass and Dryas)2,4.

Function

The function of the nest residence is to provide protection, shelter, and the required conditions for egg laying, incubation, and hatching. 

Damage or destruction of the residence

Any activity that destroys the function of the nest would constitute damage or destruction of the residence.  This would include, but is not limited to, preventing access to the nest, moving, taking or otherwise disturbing the eggs, destroying the nest, or changes to the microclimate of the nest (such as to the amount of light or internal temperature).

Period and frequency of occupancy

The nest should remain a residence from the time of construction of the nest until the chicks hatch and leave the nest. Nests were apparently initiated from mid to late June, and hatched from early to mid-July1. Young likely leave the nest within a day or two of hatch.

Additional information

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