Haematopodidae – Oystercatchers

African Black Oystercatcher Haematopus moquini ©Trevor Hardaker Website

The Haematopodidae or oystercatchers are a group of waders forming the family Haematopodidae, which has a single genus, Haematopus. They are found on coasts worldwide apart from the polar regions and some tropical regions of Africa and South East Asia. The exception to this is the Eurasian Oystercatcher and the South Island Oystercatcher, both of which breed inland, far inland in some cases. In the past there has been a great deal of confusion as to the species limits, with discrete populations of all black oystercatchers being afforded specific status but Pied Oystercatchers being considered one single species.

The different species of oystercatcher show little variation in shape or appearance. They range from 39cm to 50cm in length and 72cm to 91cm in wingspan. The Eurasian Oystercatcher is the lightest on average, at 526g, while the Sooty Oystercatcher is the heaviest, at 819g. The plumage of all species is either all-black, or black (or dark brown) on top and white underneath. The variable oystercatcher is slightly exceptional in being either all-black or pied. They are large, obvious, and noisy plover-like birds, with massive long orange or red bills used for smashing or prying open molluscs. The bill shape varies between species, according to the diet. Those birds with blade-like bill tips pry open or smash mollusc shells, and those with pointed bill tips tend to probe for annelid worms. They show sexual dimorphism, with females being longer-billed and heavier than males.

The diet of oystercatchers varies with location. Species occurring inland feed upon earthworms and insect larvae. The diet of coastal oystercatchers is more varied, although dependent upon coast type; on estuaries bivalves, gastropods and polychaete worms are the most important part of the diet, whereas rocky shore oystercatchers prey upon limpets, mussels, gastropods, and chitons. Other prey items include echinoderms, fish, and crabs.

Nearly all species of oystercatcher are monogamous, although there are reports of polygamy in the Eurasian Oystercatcher. They are territorial during the breeding season (with a few species defending territories year round). There is strong mate and site fidelity in the species that have been studied, with one record of a pair defending the same site for 20 years. A single nesting attempt is made per breeding season, which is timed over the summer months. The nests of oystercatchers are simple affairs, scrapes in the ground which may be lined, and placed in a spot with good visibility. The eggs of oystercatchers are spotted and cryptic. Between one and four eggs are laid, with three being typical in the Northern Hemisphere and two in the south. Incubation is shared but not proportionally, females tend to take more incubation and males engage in more territory defence. Incubation varies by species, lasting between 24–39 days. Oystercatchers are also known to practice ‘egg dumping’. Like the cuckoo, they sometimes lay their eggs in the nests of other species such as gulls, abandoning them to be raised by those birds.

According to the IOC there are just 11 extant species of Oystercatcher, which are:

Magellanic Oystercatcher Haematopus leucopodus
Blackish Oystercatcher Haematopus ater
Black Oystercatcher Haematopus bachmani
American Oystercatcher Haematopus palliatus
African Oystercatcher Haematopus moquini
Eurasian Oystercatcher Haematopus ostralegus
South Island Oystercatcher Haematopus finschi
Pied Oystercatcher Haematopus longirostris
Variable Oystercatcher Haematopus unicolor
Chatham Oystercatcher Haematopus chathamensis
Sooty Oystercatcher Haematopus fuliginosus

Number of Species
  • Number of bird species: 11

Useful Reading
  • Geographical Variation in Waders

    by Meinte Engelmoer and Cees S Roselaar331 pages, figs, tabs, maps.Kluwer Academic Publishers ISBN: 0792350200 Buy this book from NHBS.com
  • Shorebirds

    (WorldLife Library) by Des Thimpson, Ingvar Byrkjedal 2001 ISBN: 1841070750 Buy this book from NHBS.com
  • Shorebirds

    An Identification Guide to the Waders of the World by Pter Hayman, John Marchant and Tony Prater - Helm 1986 ISBN: 0713635096 Buy this book from NHBS.com
  • Shorebirds of North America - The Photographic guide

    by Dennis Paulson Christopher Helm 2005. Price ?24.99p ISBN: 071367377X Buy this book from NHBS.com
  • Waders of Europe, Asia & North America

    by Stephen Message & Don Taylor published by Christopher Helm 2006 price ?24.99p See Fatbirder Review ISBN: 071365290X Buy this book from NHBS.com
Organisations
  • International Wader Study Group

    Website
    The International Wader Study Group (IWSG) is an association of amateurs and professionals from all parts of the world interested in Charadrii (waders or shorebirds). Membership of the WSG is currently over 650 worldwide. Members can be found in over 50 countries around the world, including all European countries and the Americas, Asia, Africa and Australasia. The interests of the group have diversified from its original focus from ringing and migration-related studies to embrace all aspects of wader biology.
  • Western Atlantic Shorebird Association

    Website
    The first research project to be part of WASA is the International Banding Project which is being led by Professor Allan Baker, Canada and Patricia M. Gonz
  • Western Hemisphere Shorebird Reserve Network

    Website
    WHSRN is a voluntary, non-regulatory coalition of over 200 private and public organizations in seven countries working together to study and conserve shorebirds throughout their habitats. Participation in WHSRN provides the site with international recognition as a major host for shorebirds
Forums & Mailing Lists
Other Links
  • Wader Quest

    Website
    It is vital to to take action to prevent the Spoon-billed Sandpiper from becoming extinct. Wader Quest is an attempt to raise money and awareness to the plight of, not just these tiny wanderers but of wader species worldwide…

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