Bristle-thighed Curlew
Encyclopedia
The Bristle-thighed Curlew, Numenius tahitiensis, is a large shorebird
that breeds in Alaska
and winters on tropical Pacific islands. It has a long, decurved bill and bristled feathers at the base of the legs. Its length is about 43 cm and wingspan about 84 cm (females averaging bigger than males). The size and shape are the same as the Whimbrel
's, and the plumage
is similar, spotted brown on their upper body with a light belly and rust-colored or buffy tail. The bigger buff spots on the upper body, unmarked light belly and barely marked flanks, tail color, and pale buffy-orange rump distinguish it from the Whimbrel
.
The population is estimated at 7,000.
Bristle-thighed Curlews feed on a wide variety of vegetation such as flower
s and berries and on insects, sea life, and other bird's eggs
, which they use rocks to break open—the only tool use among shorebirds.
The bird is rarely seen near populated land masses, with only a handful of sightings in Canada
, California
and Oregon
. It was first described scientifically during James Cook
's visits to Tahiti
in the 18th century, but its nesting grounds were not identified until 1948.
Nesting grounds are on the lower Yukon River
and Seward Peninsula
, with the birds preferring low-lying tundra
near the shoreline. Nests
are built in ground depressions and lined with tundra moss. Eggs are greenish with brown spots, with four to a clutch and one brood per season. Incubation lasts 25 days, with both parents tending the nest and protecting the newly hatched chicks.
Adults leave their chicks at about five weeks of age to migrate
south. The chicks continue to feed until they are able to make the journey. The first leg of the migration includes a nonstop 4,000 km flight from Alaska to Laysan. They can make non-stop flights in excess of 6,000 km.
Bristle-thighed Curlews are unique among shorebirds in that they are flightless during molt. Also, their migration departures consist of small flocks and have no diurnal patterns.
Its winter habitat is tropical Oceania
, and includes Micronesia
, Fiji
, Tuvalu
, Tonga
, Hawaiian Islands
, Samoa
, and French Polynesia
. There is concern over encroachment and introduced predators in their winter habitat.
Wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...
that breeds in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
and winters on tropical Pacific islands. It has a long, decurved bill and bristled feathers at the base of the legs. Its length is about 43 cm and wingspan about 84 cm (females averaging bigger than males). The size and shape are the same as the Whimbrel
Whimbrel
The Whimbrel Numenius phaeopus, is a wader in the large family Scolopacidae. It is one of the mostwidespread of the curlews, breeding across much of subarctic North America, Europe and Asia as far south as Scotland....
's, and the plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is similar, spotted brown on their upper body with a light belly and rust-colored or buffy tail. The bigger buff spots on the upper body, unmarked light belly and barely marked flanks, tail color, and pale buffy-orange rump distinguish it from the Whimbrel
Whimbrel
The Whimbrel Numenius phaeopus, is a wader in the large family Scolopacidae. It is one of the mostwidespread of the curlews, breeding across much of subarctic North America, Europe and Asia as far south as Scotland....
.
The population is estimated at 7,000.
Bristle-thighed Curlews feed on a wide variety of vegetation such as flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s and berries and on insects, sea life, and other bird's eggs
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
, which they use rocks to break open—the only tool use among shorebirds.
The bird is rarely seen near populated land masses, with only a handful of sightings in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. It was first described scientifically during James Cook
James Cook
Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...
's visits to Tahiti
Tahiti
Tahiti is the largest island in the Windward group of French Polynesia, located in the archipelago of the Society Islands in the southern Pacific Ocean. It is the economic, cultural and political centre of French Polynesia. The island was formed from volcanic activity and is high and mountainous...
in the 18th century, but its nesting grounds were not identified until 1948.
Nesting grounds are on the lower Yukon River
Yukon River
The Yukon River is a major watercourse of northwestern North America. The source of the river is located in British Columbia, Canada. The next portion lies in, and gives its name to Yukon Territory. The lower half of the river lies in the U.S. state of Alaska. The river is long and empties into...
and Seward Peninsula
Seward Peninsula
The Seward Peninsula is a large peninsula on the western coast of the U.S. state of Alaska. It projects about into the Bering Sea between Norton Sound, the Bering Strait, the Chukchi Sea, and Kotzebue Sound, just below the Arctic Circle...
, with the birds preferring low-lying tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
near the shoreline. Nests
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
are built in ground depressions and lined with tundra moss. Eggs are greenish with brown spots, with four to a clutch and one brood per season. Incubation lasts 25 days, with both parents tending the nest and protecting the newly hatched chicks.
Adults leave their chicks at about five weeks of age to migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
south. The chicks continue to feed until they are able to make the journey. The first leg of the migration includes a nonstop 4,000 km flight from Alaska to Laysan. They can make non-stop flights in excess of 6,000 km.
Bristle-thighed Curlews are unique among shorebirds in that they are flightless during molt. Also, their migration departures consist of small flocks and have no diurnal patterns.
Its winter habitat is tropical Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
, and includes Micronesia
Micronesia
Micronesia is a subregion of Oceania, comprising thousands of small islands in the western Pacific Ocean. It is distinct from Melanesia to the south, and Polynesia to the east. The Philippines lie to the west, and Indonesia to the southwest....
, Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, Tuvalu
Tuvalu
Tuvalu , formerly known as the Ellice Islands, is a Polynesian island nation located in the Pacific Ocean, midway between Hawaii and Australia. Its nearest neighbours are Kiribati, Nauru, Samoa and Fiji. It comprises four reef islands and five true atolls...
, Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
, Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
, Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...
, and French Polynesia
French Polynesia
French Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
. There is concern over encroachment and introduced predators in their winter habitat.