Crab-plover

Last updated

Crab-plover
Reiherlaufer.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Suborder: Lari
Family: Dromadidae
GR Gray, 1840
Genus: Dromas
Paykull, 1805
Species:
D. ardeola
Binomial name
Dromas ardeola
Paykull, 1805
Dromas ardeola map.png

The crab-plover or crab plover (Dromas ardeola) is a bird related to the waders, but sufficiently distinctive to merit its own family Dromadidae. Its relationship within the Charadriiformes is unclear, some have considered it to be closely related to the thick-knees, or the pratincoles, while others have considered it closer to the auks and gulls. It is the only member of the genus Dromas and is unique among waders in making use of ground warmth to aid incubation of the eggs.

Contents

Description

The feet are partially webbed DromasLeMessurier.jpg
The feet are partially webbed

This bird resembles a plover, but has very long grey legs and a strong heavy black bill similar to a tern. Its black-and-white plumage and long-necked upright posture with heavy bill makes it distinctive and unmistakable. Its bill is unique among waders, and specialised for eating crabs. It has partially webbed toes. The plumage is white except for black on its back and in the primary feathers of the wings. They are noisy birds, calling frequently on their breeding sites and in their wintering grounds. The usual call is a ka similar to that of the bar-tailed godwit but repeated rapidly. Flocks may produce a whinnying sound that rises and at in the breeding season produce whistling kew-ki-ki notes. [2]

Males and females are not easily distinguished but males have a heavier and longer bill. Juveniles have the black on the mantle, greyish and remain in this plumage for a year. Flocks fly in lines or "V" formations. [2]

The crab-plover is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

Range

It is resident on the coasts and islands of the Indian Ocean, where it feeds on crabs and other small animals. They are gregarious and will feed in large groups, at night and during dawn and dusk as well as during the day; this crepuscular and nocturnal behaviour is more common during the breeding season. They breed around the Arabian Sea, Gulf of Oman and the Persian Gulf, Red Sea and Somalia in the months of April to July then disperse across the Indian Ocean in August as far as the Andaman Islands and Sri Lanka in the east and Tanzania and Madagascar. [2]

Habits

Crab-plover eating a crab Dromas ardeola Kenya 1.jpg
Crab-plover eating a crab

The crab-plover is unusual for waders in that it nests in burrows in sandy banks. In the Red Sea region, the breeding season begins around the middle of May. [3] It is a colonial breeder, nesting in colonies as large 1500 pairs. It lays one white egg, occasionally two, which are large for its body size. The nest burrow temperature is optimal due to solar radiation and the parents are able to leave the nest unattended for as long as 58 hours. [4] The chicks are also unique for the usually nidifugous waders in being unable to walk and remain in the nest for several days after hatching, having food brought to them. Even once they fledge they have a long period of parental care afterwards. Both males and females take care of the young. [5]

Notes

  1. BirdLife International (2019). "Dromas ardeola". IUCN Red List of Threatened Species . 2019: e.T22694081A155499202. doi: 10.2305/IUCN.UK.2019-3.RLTS.T22694081A155499202.en . Retrieved 12 November 2021.
  2. 1 2 3 Hayman, P.; J. Marchant; T. Prater (1986). Shorebirds: an identification guide to the waders of the world. Croom Helm, London. pp. 222–223.
  3. Baker, ECS (1929). "The game birds of the Indian empire. Part 8. The waders and other Semi-sporting birds". J. Bombay Nat. Hist. Soc. 33 (2): 223–228.
  4. De Marchi, G.; Chiozzi, G.; Fasola, M. (2008). "Solar incubation cuts down parental care in a burrow nesting tropical shorebird, the crab plover Dromas ardeola". Journal of Avian Biology. 39 (5): 484–486. doi:10.1111/j.0908-8857.2008.04523.x.
  5. Szekely, Tamas; John D. Reynolds (1995). "Evolutionary Transitions in Parental Care in Shorebirds". Proc. R. Soc. B. 262 (1363): 57–64. doi:10.1098/rspb.1995.0176.

Related Research Articles

<span class="mw-page-title-main">Sandpiper</span> Family of birds

Scolopacidae is a large family of shorebirds, or waders, which mainly includes many species known as sandpipers, but also others such as curlews and snipes. The majority of these species eat small invertebrates picked out of the mud or soil. Different lengths of bills enable different species to feed in the same habitat, particularly on the coast, without direct competition for food.

<span class="mw-page-title-main">Ibisbill</span> Species of bird

The ibisbill is a bird related to the waders, but sufficiently distinctive to merit its own family Ibidorhynchidae. It is grey with a white belly, red legs and long down-curved bill, and a black face and black breast band. It occurs on the shingle riverbanks of the high plateau of central Asia and the Himalayas.

<span class="mw-page-title-main">Charadriidae</span> Family of birds

The bird family Charadriidae includes the plovers, dotterels, and lapwings. The family contains 69 species that are divided into 10 genera.

<span class="mw-page-title-main">American avocet</span> Species of bird

The American avocet is a large wader in the avocet and stilt family, Recurvirostridae, found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill from side to side in water as it seeks crustacean and insect prey.

<span class="mw-page-title-main">Killdeer</span> Shorebird found in the Americas

The killdeer is a large plover found in the Americas. It gets its name from its shrill, two-syllable call, which is often heard. It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae. Three subspecies are described. Its upperparts are mostly brown with rufous fringes, the head has patches of white and black, and two black bands cross the breast. The belly and the rest of the breast are white. The nominate subspecies breeds from southeastern Alaska and southern Canada to Mexico. It is seen year-round in the southern half of its breeding range; the subspecies C. v. ternominatus is resident in the West Indies, and C. v. peruvianus inhabits Peru and surrounding South American countries throughout the year. North American breeders winter from their resident range south to Central America, the West Indies, and the northernmost portions of South America.

<span class="mw-page-title-main">Pacific golden plover</span> Species of bird

The Pacific golden plover is a migratory shorebird that breeds during Alaska and Siberia summers. During nonbreeding season, this medium-sized plover migrates widely across the Pacific.

<span class="mw-page-title-main">Willet</span> Species of bird

The willet is a large shorebird in the family Scolopacidae. It is a relatively large and robust sandpiper and is the largest of the species called "shanks" in the genus Tringa. Its closest relative is the lesser yellowlegs, a much smaller bird with a very different appearance apart from the fine, clear, and dense pattern of the neck, which both species show in breeding plumage. It breeds in North America and the West Indies and winters in southern North America, Central America, the West Indies and South America.

<span class="mw-page-title-main">Red knot</span> Species of bird

The red knot or just knot is a medium-sized shorebird which breeds in tundra and the Arctic Cordillera in the far north of Canada, Europe, and Russia. It is a large member of the Calidris sandpipers, second only to the great knot. Six subspecies are recognised.

<span class="mw-page-title-main">White-rumped sandpiper</span> Species of bird

The white-rumped sandpiper is a small shorebird that breeds in the northern tundra of Canada and Alaska. This bird can be difficult to distinguish from other similar tiny shorebirds; these are known collectively as "peeps" or "stints".

<span class="mw-page-title-main">Long-billed dowitcher</span> Species of bird

The long-billed dowitcher is a medium-sized shorebird with a relatively long bill belonging to the sandpiper family, Scolopacidae. In breeding plumage, adults are characterized by a beautiful rufous head and underparts with a darker mottled back and a large white upper rump only seen in flight. They feed in various freshwater habitats with their bill underwater in a "sewing machine" motion and are known to have an exciting mating display where males chase females in flight. The genus, Limnodromus is Ancient Greek from limne, "marsh" and dromos, "racer". The specific scolopaceus is Neo-Latin for "snipe-like", from Latin scolopax, scolopacis, a snipe or woodcock. The English name is from Iroquois and was first recorded in 1841.

<span class="mw-page-title-main">Egg incubation</span> The process by which certain egg-laying animals hatch their eggs

Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possibly by brooding and hatching the egg.

<span class="mw-page-title-main">Bird nest</span> Place where a bird broods its eggs

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 Montezuma oropendola or the village weaver—that is too restrictive a definition. For some species, a nest is simply a shallow depression made in sand; for others, it is the knot-hole left by a broken branch, a burrow dug into the ground, a chamber drilled into a tree, an enormous rotting pile of vegetation and earth, a shelf made of dried saliva or a mud dome with an entrance tunnel. The smallest bird nests are those of some hummingbirds, tiny cups which can be a mere 2 cm (0.8 in) across and 2–3 cm (0.8–1.2 in) high. At the other extreme, some nest mounds built by the dusky scrubfowl measure more than 11 m (36 ft) in diameter and stand nearly 5 m (16 ft) tall. The study of birds' nests is known as caliology.

<span class="mw-page-title-main">Kittlitz's plover</span> Species of bird

Kittlitz's plover is a small shorebird in the family Charadriidae that breeds near coastal and inland saltmarshes, sandy or muddy riverbanks or alkaline grasslands with short vegetation. It is native to much of Sub-Saharan Africa, the Nile Delta and Madagascar. It is thought to be mainly polygamous and has monomorphic plumage.

<span class="mw-page-title-main">Banded lapwing</span> Species of bird

The banded lapwing is a small to medium-sized shorebird, found in small parties or large flocks on bare ground in open grasslands, agricultural land and open savannah. It is native to Australia and in the past considered as a game bird for hunting. Population estimate is 25 000 - 1 000 000. Other names include banded, black-breasted, brown flock and plain plover.

<span class="mw-page-title-main">Collared plover</span> Species of bird

The collared plover is a small shorebird in the plover family, Charadriidae. It lives along coasts and riverbanks of the tropical to temperate Americas, from central Mexico south to Chile and Argentina.

<span class="mw-page-title-main">White-fronted plover</span> Species of shorebird of the family Charadriidae from Sub-Saharan Africa and Madagascar

The white-fronted plover or white-fronted sandplover is a small shorebird of the family Charadriidae that inhabits sandy beaches, dunes, mudflats and the shores of rivers and lakes in sub-saharan Africa and Madagascar. It nests in small shallow scrapes in the ground and lays clutches of one to three eggs. The species is monogamous and long-lived, with a life expectancy of approximately 12 years. The vast majority of pairs that mate together stay together during the following years of breeding and retain the same territory. The white-fronted plover has a similar appearance to the Kentish plover, with a white fore crown and dark bands connecting the eyes to the bill.

<span class="mw-page-title-main">Kentish plover</span> Species of bird

The Kentish plover is a small wader of the family Charadriidae that breeds on the shores of saline lakes, lagoons, and coasts, populating sand dunes, marshes, semi-arid desert, and tundra. Both male and female birds have pale plumages with a white underside, grey/brown back, dark legs and a dark bill; however, additionally the male birds also exhibit very dark incomplete breast bands, and dark markings either side of their head, therefore the Kentish plover is regarded as sexually dimorphic.

<span class="mw-page-title-main">Long-billed plover</span> Species of bird

The long-billed plover is a species of wading bird in the family Charadriidae. It can be found in Bangladesh, Bhutan, Brunei, Cambodia, China, Hong Kong, India, Indonesia, Japan, Laos, Malaysia, Mongolia, Myanmar, Nepal, North Korea, Russia, South Korea, Sri Lanka, Taiwan, Thailand, and Vietnam. The long-billed plover is a migratory bird, so it breeds and spends the winter in different parts of its range. This bird can often be spotted along the shores of rivers, streams, in wetlands, and rice fields. It forages on the shoreline primarily for aquatic insects, insect larvae, and other invertebrates. It is difficult to distinguish between male and female individuals because of their similar plumage. The breeding season starts at the end of February or early March and ends in July. A male and a female forms a monogamous pair and maintains their territory throughout the breeding season. A global population survey in 2016 assessed the long-billed plover as a species of least concern on the International Union for Conservation of Nature (IUCN) Red List.

<span class="mw-page-title-main">Madagascar plover</span> Species of bird

The Madagascar plover, also known as the black-banded plover, is a small monogamous shorebird in the family Charadriidae, native to western Madagascar. It inhabits shores of lagoons, coastal grasslands, and breeds in salt marshes. These plovers mainly nest in open grassland and dry mudflats surrounding alkaline lakes. The species is classified as vulnerable by the IUCN because of its low breeding success, slow reproductive rate, and weak adaptation to increasing habitat loss, leading to declining population numbers.

<span class="mw-page-title-main">Broodiness</span> Behavioral tendency to sit on a clutch of eggs to incubate them

Broodiness is the action or behavioral tendency to sit on a clutch of eggs to incubate them, often requiring the non-expression of many other behaviors including feeding and drinking. Being broody has been defined as "Being in a state of readiness to brood eggs that is characterized by cessation of laying and by marked changes in behavior and physiology". Broodiness is usually associated with female birds, although males of some bird species become broody and some non-avian animals also show broodiness.

References