Numenius phaeopus, Whimbrel

Written by on November 19, 2010 in Bali Bird with 0 Comments

Numenius phaeopus, Whimbrel, Gajahan Penggala WhimbrelsNumenius phaeopus, Whimbrel, Gajahan Penggala are large waders with distinctive long down-curved bills. These bills allow them to probe deeply into mud for titbits. And possibly gave rise to one of their Malay names which means "elephant bird"!

Whimbrels eat mostly burrowing crabs. The next major item on the menu are fish. But they will eat a wide variety of crustaceans, aquatic invertebrates, insects, worms and molluscs. They also snack on seeds, berries and leaves, particularly in late summer as insect populations begin to dwindle.

Whimbrels probe deeply and move as they feed. They may also pick off food found on the surface. They can take large prey, tearing it to pieces before eating it. In India, they pull fiddler crabs out of their burrows, tear off their larger claw before swallowing the titbit. A muddy food item may be rinsed before it is eaten.

Whimbrels forage on both mud and sandy surfaces, but avoid very soft mud. They are only found in coastal areas and do not forage inland.

Whimbrels generally feed alone or in small, spread out parties. At most times of year, they defend some kind of territory. On migration, they maintain a feeding territory that is guarded against other Whimbrels. But Whimbrels roost and migrate in large flocks. They prefer to roost on exposed shoals, tops of mangrove trees or in shallowly flooded clearings in mangroves which face the open sea.

Breeding (May-August): Whimbrels breed in the subarctic and arctic from Iceland across Eurasia, Alaska and Canada. They prefer to nest in boreal or low-arctic moorland and tundra next to the treeline. The male’s courtship includes a high circling song flight comprising a prolonged bubbling. They don’t have different summer and winter plumage.

Whimbrel nests are just a shallow depression on the ground, usually concealed in low grass or heather. They may also make a nest on top of a mound of moss or grass that is surrounded at the base with water. The hollow is lined with soft grasses, mosses and lichens. 2-5, usually 4 eggs are laid; these are bluish green to a light olive green with lavender and brown markings. Both parents incubate (22-28 days) and raise the young. As soon as the chicks are dry, they leave the nest and stay hidden among the surrounding vegetation. Both parents care for the chicks until they fledge in 35-40 days.

Migration: Those Whimbrels that visit Singapore breed in Northeast Asia, migrating in winter to India, southern China, Southeast Asia to the Philippines and the Sundas. They migrate with other shorebirds, and often act as a sentinel species. Very wary, Whimbrels are often the first to alert the other birds to danger. Their peak arrival in Singapore is September-November, although a small number may be found throughout the year. Probably because many first year birds may remain in their wintering quarters throughout the summer. During migration, the Whimbrel roosts in mangroves, feeds on mudflats at the tideline with other waders. They may also be found inland, both around wetlands as well as short dry grassland, farmland, golf courses, parks.

Status and threats: Whimbrels are among the most abundant Curlews because of their extensive breeding range. Adult Whimbrels have few natural predators, aside from foxes and larger raptors. Few succumb to predation during migration, probably because they are very vigilant. Human impact is the biggest threat. Whimbrels are affected by habitat loss of nesting sites and refuelling staging posts along the migration route, and pollution of shorelines. In the early 1900s, they were hunted in the US as they migrated south. The slaughter had reduced populations there from thousands to a few hundred. Although hunting is less widespread now, there has been no apparent recovery to pre-hunting levels. They continue to be hunted in their wintering grounds, such as in Thailand.

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