Avocet (Recurvirostra avosetta)

Description

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Avocet fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Avocet description

An elegant and striking bird ⁽³⁾, the avocet (Recurvirostra avosetta) gains its common name from the black colouration on its head, which resembles the cap once worn by advocates, a term used for lawyers in certain countries ⁽⁴⁾. The rest of the plumage is primarily white, with a black band on the wing, black wing tips and a black striped pattern on the back ⁽³⁾. One of the most distinctive features of the avocet is its long, slender, upturned bill. The bill is black and is longer in the male than the female ⁽²⁾.

The juvenile avocet is similar in appearance to the adult, but with brown colouration in the areas where the adult is black. The plumage on the juvenile’s upperparts is also mottled brown ^{(2) (3)}. The long legs are conspicuously blue-grey in both sexes and dangle well beyond the tail when the avocet is in flight ^{(2) (3)}.

The vocalisations of the avocet include a fluted ‘kloo-it’ or ‘kleep’ ⁽³⁾, which is heard more often during the breeding season ⁽²⁾.

Also known as

Pied avocet.

French

Avocette à tête noire.

Size

Length: 42 - 45 cm ⁽²⁾

Wingspan: 20.6 - 24 cm ⁽²⁾

Avocet biology

A gregarious species ^{(2) (7)}, the avocet breeds from April to August in large colonies of between 10 and 70 pairs ⁽⁵⁾. Sexual maturity is reached at two years old, when the avocet will find a breeding ground, often different to where it was reared. This breeding ground is where the avocet will return each year to breed ⁽⁷⁾.

The nest of the avocet consists of a scrape made in sand, mud or short vegetation on the ground ⁽⁵⁾, into which three or four eggs are laid ⁽⁸⁾. The nests within the colony are usually only one metre away from each other ⁽²⁾, with some recorded only 20 to 30 centimetres apart ⁽⁵⁾. The male and female avocet stay together for the breeding season ⁽⁷⁾, sharing responsibility for incubating the eggs for between 23 and 25 days ⁽⁸⁾. The chicks fledge the nest after 35 to 42 days ⁽⁸⁾. The pair bond between the male and female is only sustained for one breeding season, after which they separate and join a flock to begin migration ⁽⁷⁾.

The migration of northern populations begins between August and October, with the avocets heading south in a flock, stopping in certain areas in great numbers ⁽⁵⁾. Several thousand individuals may roost together and groups of between 5 and 30 forage collectively ⁽⁵⁾.

The diet of the avocet is primarily composed of aquatic invertebrates, such as insects, crustaceans, worms and molluscs, as well as small fish and plants ⁽⁵⁾. It usually takes food from exposed mud or from water ⁽²⁾, using a characteristic foraging technique that involves a sweeping motion of the beak, and it also upends in deep water to reach prey ^{(2) (3)}.

A highly territorial bird, the avocet will chase away any unwelcome visitors while breeding, lunging towards them with a lowered head and neck, and may even drive away much larger birds such as the common shelduck (Tadorna tadorna) ⁽²⁾. 

Avocet range

The avocet has an extremely large range across Europe, Africa and Asia. In Africa, it occurs from the most northerly tip of the Rift Valley south to the South African Cape, while its Eurasian distribution extends from the United Kingdom east to northern China ^{(5) (6)}.

This species is largely migratory, with northern populations generally moving south for the winter. However, avocets in much of Africa and parts of western Europe remain resident year-round ^{(2) (4) (6)}. 

Avocet habitat

Throughout the breeding season, avocets colonise flat exposed areas such as mudflats and sandbanks in shallow, saline or brackish wetlands ^{(2) (5)}, in areas with minimal vegetation ⁽²⁾. These become exposed by receding waters throughout the summer, creating extra feeding grounds for this species ⁽⁵⁾.

Outside of the breeding season, the avocet inhabits coastlines and surrounding muddy areas ⁽²⁾, such as estuaries, lagoons, sandbanks and mudflats, as well as inland saline lakes ⁽⁵⁾. 

Avocet status

The avocet is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Avocet threats

The avocet population within Europe is threatened by pollution of wetland habitats. Human disturbance has also affected the wintering sites of this species, which have been subject to pollution, river flow reduction, reclamation of land and infrastructure development ⁽⁵⁾.

The avocet is vulnerable to diseases such as avian botulism and influenza, which pose a major threat to the future survival of this migratory bird ⁽⁵⁾.

Avocet conservation

The avocet is included in the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) ⁽⁹⁾ and Appendix II of the Convention on Migratory Species ⁽¹⁰⁾. In the UK it is also named under Schedule 1 of the Wildlife & Countryside Act 1981, which protects the avocet by law and makes it an offence to disturb the birds or their nesting areas ⁽¹¹⁾.

Conservation measures for this species have included efforts to create artificial nesting sites along certain coastlines to attract avocet breeding pairs. Cattle grazing on coastal grasslands is also beneficial to the avocet ⁽⁵⁾.

The avocet is the emblem of the Royal Society for the Protection of Birds (RSPB), as it is symbolic of a successful conservation programme within the United Kingdom ⁽⁷⁾. Throughout the 19th century, the avocet was on the brink of extinction in the UK, but managed to recolonise beach areas in East Anglia during World War II, increasing its population numbers to a sustainable level ⁽⁶⁾. 

Find out more

Find out more about the avocet and its conservation:

• BirdLife International - Pied avocet:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=3107
• RSPB - Avocet:
  http://www.rspb.org.uk/wildlife/birdguide/name/a/avocet/index.aspx
• BBC Wildlife Finder - Pied avocet:
  http://www.bbc.co.uk/nature/life/Pied_Avocet
  http://www.bbc.co.uk/nature/life/Pied_Avocet

You can see the avocet by visiting the Thames Estuary, Essex:

• Royal Geographical Society’s Discovering Britain walks: 
  http://www.discoveringbritain.org/walks/region/east-of-england/essex-estuary.html

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Glossary

Avian botulism

A paralytic, often fatal disease of birds caused by the ingestion of toxin produced by the bacterium Clostridium botulinum.

Avian influenza

Also known as “bird flu”, a contagious disease caused by any strain of influenza virus that is carried by and primarily affects birds.

Brackish

Slightly salty water, usually a mixture of salt and freshwater, such as that found in estuaries.

Crustaceans

Diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Incubation

The act of incubating eggs, that is, keeping them warm so that development is possible.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following: a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Territorial

Describes an animal, a pair of animals or a group that occupies and defends an area.

References

1.  IUCN Red List (January, 2012)
   http://www.iucnredlist.org/
2. Hayman, P., Marchant, J. and Prater, T. (1986) Shorebirds. Christopher Helm Publishers, London.
3. Peterson, R.T., Mountfort, G. and Hollom, P.A.D. (1993) A Field Guide to the Birds of Britain and Europe. Houghton Mifflin Company, New York.
4. MobileReference. (2008) The Illustrated Encyclopedia of European Birds: An Essential Guide to Birds of Europe. MobileReference, Boston.
5. BirdLife International - Pied avocet
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=3107
6. Parkin, D.T. and Knox, A.G. (2010) The Status of Birds in Britain and Ireland. A&C Black, London.
7. RSPB - Avocet (January, 2012)
   http://www.rspb.org.uk/wildlife/birdguide/name/a/avocet/index.aspx
8. British Trust for Ornithology - Avocet (January, 2012)
   http://blx1.bto.org/birdfacts/results/bob4560.htm
9. Agreement on the Conservation of African-Eurasian Migratory Waterbirds (January, 2012)
   http://www.unep-aewa.org/
10. Convention on Migratory Species (January, 2012)
    http://www.cms.int/
11. Wildlife and Countryside Act (January, 2012)
    http://www.legislation.gov.uk/ukpga/1981/69