Bristle-thighed Curlew, Numenius tahitiensis
The Bristle-thighed Curlew, (Numenius tahitiensis), is a species of bird found in Alaska during the breeding season, and throughout the tropical Pacific islands in the winter, including Micronesia, Fiji, Tuvalu, Tonga, Hawaiian Islands, Samoa, and French Polynesia. There is some concern over human encroachment and introduced predators in this bird’s wintering habitat. This bird is a rare visitor to Canada and the Pacific US during the breeding season.
The Bristle-thighed Curlew was first described during James Cook’s visits to Tahiti in the 18th century, but its breeding grounds were not identified until 1948.
The adult is 17 inches in length with a 33-inch wingspan; the female is a larger than the male. Its bill is long and downward-curved. It has bristled feathers at the base of its legs — hence the bird’s common name. It is close in size and shape to the Whimbrel, and plumages are also similar. The upper body is spotted brown with a light belly and rust-colored or pale yellowish tail. Bigger yellowy spots on the upper body, unmarked light belly and barely marked flanks, tail color, and pale yellowy-orange rump distinguish it from the Whimbrel.
The diet of this bird consists of a wide variety of vegetation such as flowers and berries, as well as insects, marine life, and the eggs of other birds. It uses rocks to break open eggs — the only tool use seen in shorebirds.
The nesting grounds of the Bristle-thighed Curlew are found on the lower Yukon River and Seward Peninsula, with birds preferring low-lying tundra near the shoreline. The nest is built in a ground depression and lined with tundra moss. The eggs are greenish with brown spots. Up to four eggs are laid in a single brood. Incubation lasts 25 days, and both parents tend to the nest and protect the newborn chicks.
The chicks are left at about five weeks of age as the adults begin their migration route south. The chicks continue to feed at the breeding grounds until they are strong enough to take flight and make the journey themselves. The first leg of the migratory journey consists of a nonstop 2,500 mile flight from Alaska to Laysan. This bird is capable of making nonstop flights in excess of 3,700 miles.
This species is unique among shorebirds in that they are flightless during molt (periodical feather shedding). The global population of this bird is estimated at 7,000 individuals.
Image Credit: NPS/Wikipedia (public domain)