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Shorebirds

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[edit] Bird Family – Waders or Shorebirds Order Charadriiformes

Waders are also called shorebirds; Wade literally means to walk thru water. And the wading birds are called waders, are members of the order Charadriiformes, excluding groups like skuas, gulls, terns, skimmers, auks, pratincoles. So there are arround 210 species, most of which are associated with wetland or coastal environments. Most Wader birds have long legs, adapted to life on intertidal shores, feeding on invertebrates. These birds are so influenced by the tide that they live two 12 hour periods rather than one 24 hour day. They feed for 8 hours then rest for four hours, repeating the pattern day or night.

Many shorebirds migrate, making very long-distance journeys, spanning the globe in a north-south direction. Most of the long-distance migrating birds breed in the Arctic regions. Some of the Arctic species, such Little Stint are amongst the longest distance migrants. Many species of Arctic and temperate regions are strongly migratory, but tropical birds are often resident, or move only in response to rainfall patterns. Flyways are the regular routes taken by migrating birds. The flocks must rely on a series of 3 or 4 stopovers on their journey, If just one of these points becomes unsafe or degraded it can spell disaster for the whole migration. That makes wader bird conservation a very complex business.

Wader birds lead double lives, changing plumage for different times of the year. In non breeding season we see their white/grey plumage, but before heading off for their breeding ground they change into their breeding colors of chestnut, gold & bronze. They will go through two full body moults each year and change their big feathers once a year.

Typical shorebirds feed by probing in the mud or picking items off the surface in both coastal and freshwater environments. The shape and size of their bill gives a clue to their preferred diet and habitat. The long probing bill of the eastern curlew is ideal for fishing out worms and crustaceans from deep mud whereas the short, stubby bill of the ruddy turnstone can flip aside stones and shells on a rocky foreshore to expose food. At low tide, regardless of day or night, shorebirds feed constantly — pecking and probing for worms, insects and crustaceans. With their highly variable and specialized bills they feed around intertidal flats, beaches, rocky headlands and along the fringes of freshwater wetlands. As the incoming tide covers these feeding areas, they begin to congregate in large numbers at relatively safe roost sites nearby. These roost sites provide areas where they can interact, preen, digest their food and rest while waiting for the ebbing tide to again expose their feeding areas. Given an abundant food source, shorebirds have the ability to quickly store the fat they need to fuel their long distance flights.

Many individual shorebirds have been recorded by birdwatchers worldwide which do not fit the characters of known species. Many of these have been suspected of being hybrids. In several cases, shorebird hybrids have been described as new species before their hybrid origin was discovered. Compared to other groups of birds (such as gulls), only a few species of shorebirds are known or suspected to hybridize, but nonetheless, these hybrids occur quite frequently in some cases.

Shorebirds or Waders includes following Family and bird groups.

Family Scolopacidae: snipe, sandpipers, phalaropes, and allies
Family Rostratulidae: painted snipe
Family Jacanidae: jacanas
Family Thinocoridae: seedsnipe
Family Pedionomidae: Plains Wanderer
Family Burhinidae: thick-knees
Family Chionididae: sheathbills
Family Pluvianellidae: Magellanic Plover
Family Ibidorhynchidae: Ibisbill
Family Recurvirostridae: avocets and stilts
Family Haematopodidae: oystercatchers
Family Charadriidae: plovers and lapwings

Plovers are small, fat-bodied shorebirds with relatively large eyes, short bulky bills, and stubby necks. The majorities of these birds either live or breed along coastal beaches, open prairie, arctic tundra, and alkali wetlands. Plovers have exceptional camouflage and are often heard before they are seen. All plovers use the 'broken wing' or distraction display to lead intruders away from their eggs or young.

Phalaropes are small swimming waders. They differ from sandpipers by having partially lobed toes. Within the phalaropes, the roles of the sexes are reversed. The females are larger and more brightly colored than the males. During nesting and mating season, the female initiates courtship rituals but the male builds the nest and incubates the eggs. When feeding, phalaropes will often spin in circles to stir up insects. Three species belong to this family: Wilson's phalarope, red-necked phalarope, and red phalarope.

Sandpipers are a large group birds that inhabit mud flats and sandy shorelines. They often gather in large numbers to feed on aquatic insects. When startled, sandpipers rise in unison and fly in arrangement to safety. Most species of sandpipers nest on the arctic tundra. Sandpipers are difficult to recognize because many species share similar plumage patterns and are often mixed with other species. Many of the sandpiper species have long pointed wings that are adapted for high speed flight and are well known for their long distance seasonal migrations.

Jacanas are from the family Jacanidae. They are found worldwide tropical zone. They are identifiable by their huge feet and claws which enable them to walk on floating vegetation in the shallow lakes which is their habitat. The females are larger than the males; the latter, as in some other wader families like the phalaropes take responsibility for incubation, and some species are polyandrous. They feed on insects and other invertebrates picked from the floating vegetation or the water’s surface.

Oystercatchers are form the family Haematopodidae belonging to a single genus Haematopus. They are large noticeable and loud plover-like birds, with strong bills used for smash open molluscs. Those birds with blade-like bill tips prise open or smash mollusk shells, and those with pointed bill tips tend to probe for worms. They are found on coasts worldwide apart from the Polar Regions.


[edit] References

  • Birdlife International
  • Threatened Birds of the World, Lynx Edicions
  • Shore birds, And Identification Guide, Peter Hayman.
  • Wetland International
  • Phylogeny and classification of birds. Sibley, Gald & Ahlquist


Arpit Deomurari
Consultant (Environment, GIS and IT)
[email protected]