Oystercatcher

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The oystercatchers are a group of crossers forming the Haematopodidae family, which has a single genus, Haematopus . They are found on beaches around the world apart from the polar regions and some tropical regions of Africa and Southeast Asia. Exceptions to this are the Eurasian oystercatcher and the South Island oystercatcher, both breeding in the interior, deep inland in some cases. In the past there has been a lot of confusion about species boundaries, with discrete populations of all black oystercatchers granted special status but the included oystercatchers are considered as a single species.

The name oystercatcher was created by Mark Catesby in 1731 as a common name for the North American species

H. palliatus, described as eating oysters. Yarrell in 1843 set this as a preferred term, replacing the old name sea cake or sea cake . The genus name Haematopus comes from the Greek haima ???? blood, pous ???? legs.

Video Oystercatcher

Description

Different species of oystercatcher show little variation in shape or appearance. They range from 39-50 cm (15-20 inches) long and 72-91 cm (28-36 inches) in wingspan. The Eurasian oystercatcher is the lightest average, at 526 g (1,160 lb), while the soot oystercatcher is the heaviest, at 819 g (1,806 lb). The feathers of all species are either all black, or black (or dark brown) on the top and white underneath. The oystercatcher variator is a bit unusual either being black or pied. They are big, clear, noisy birds like a big, long orange or red orange used to crush or pry open mollusks. The shape of the bill varies between species, according to the diet. Birds with blade-like blades dismantle open mollusc shells, and those with pointed tips tend to examine the annelid worms. They show sexual dimorphism, with women being longer billed and heavier than men.

Maps Oystercatcher

Giving Feeding

The oystercatcher diet varies with location. Species that occur on land feed on earthworms and insect larvae. Coastal oystercatcher diets are more variable, although depending on the type of beach; in bivalves estuaries, gastropods and polychaete worms are the most important part of the diet, while rocky beach oystercatchers prey on limpets, mussels, gastropods, and chitons. Other prey items include echinoderms, fish, and crabs.

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Breeding

Almost all oystercatcher species are monogamous, although there are reports of polygamy in the Eurasian oystercatcher. They are territorial during the breeding season (with some species defending the area throughout the year). There are strong couples and site loyalty to the species studied, with one note of the couple defending the same site for 20 years. A single nesting attempt is performed per mating season, which is due during the summer. Oyster nests are a simple affair, scratches on the ground that may be coated, and placed in place with good visibility. Egg oystercatcher is visible and faint. Between one and four eggs are laid, with three typical in the northern hemisphere and two in the south. Incubation is shared but disproportionately, women tend to take more incubation and men engage in more territorial defenses. Incubation varies by species, which lasts between 24-39 days. Oystercatcher is also known to practice "egg dumping." Like cuckoo, they sometimes lay their eggs in other species' nests like seagulls, leaving them to be reared by the birds.

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Preservation

The Canary Islands oystercatcher became extinct during the 20th century. The Chatham oystercatcher is endemic in the New Zealand Chatham Islands but is listed as endangered by the IUCN, while both African and Eurasian oystercatchers are considered near threatened. There have been conflicts with commercial shellfishers, but research has found that the impact of oystercatchers is much smaller than that of coastal crabs.

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Species

One of the fossil species is known: Haematopus sulcatus (Brodkorb, 1955) from the beginning of Pliocene of Florida.

src: nzbirdsonline.org.nz

References

src: c8.alamy.com

External links

• ARKive - images and movies from oystercatcher (Haematopus ostralegus)
• Oystercatcher Video in Bird Bird Collection
• Webcam Oyster breeding in Bergen
• DIRECT webcams on the beach in Namsos, Norway 2013

Source of the article : Wikipedia