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 Photo by David Flack. |
With its striking black and white plumage and upturned bill, the Avocet is one of our most distinctive waders. It's also the symbol of the RSPB and one of our great conservation success stories. Avocets used to breed along the coast from Sussex to Yorkshire, but regular taking of adults and eggs for food, egg collecting, taxidermy and other pressures eventually led to their disappearance as a British breeding bird in 1842. There was then a gap of almost 100 years before they bred again, in Ireland in 1938. But, in 1947, four pairs were found breeding at Havergate Island and Minsmere, both in Suffolk. Their preferred habitat of shallow pools with low muddy islands next to the coast is very rare in this country, and it was only because of the Second World War that conditions enabled Avocets to return.
At Havergate, a wayward bomb from a nearby firing range blew a hole in the seawall around the island. The tidal river flooded in. This created ideal conditions for the Avocets. At Minsmere, the grazing marshes were deliberately flooded to stop any invading troops, and when the water was gradually drained away, shallow pools formed, again providing ideal nesting conditions.
Luckily, lagoons for Avocets can be created, and this has happened at several nature reserves including Two Tree Island. At Minsmere. where a series of pools and islands were created, Avocets returned to breed in 1963, the first year after work started.
Today, over 100 pairs breed at both Minsmere and Havergate and, thanks to protection and creation of breeding sites elsewhere, nationally numbers have increased to over 400 pairs. Because they need shallow water and open mud, many of the sites where they nest need managing each year to stop the plants taking over again. So, on many reserves, water levels are carefully controlled and the plants are cut and burnt and islands weeded by hand to keep things just right.
Avocets normally breed for the first time at two years old, often at a different location from where they themselves were reared, but having bred successfully they will be faithful to the site in subsequent years. Pair formation starts in the late winter, and most birds are paired up by the time they reach breeding colonies. Pair-bonds are maintained for the duration of breeding season only, and break up by the time winter flocks gather.
Avocets in the UK breed in loose colonies of up to around 150 pairs. Colony size and density is determined by availability of suitable nest sites, distance to water and risk of predation. The nest, built by both sexes, is a shallow scrape on bare mud or in sparse vegetation, even in shallow water, and is composed of short pieces of stems, roots, and leaves of marsh vegetation.
A clutch of 3-4 pale buff eggs with black markings is laid at 1-2 day intervals between mid-April and late June. Incubation begins with 2nd or 3rd egg. Both sexes incubate for 23-25 days. The young can run about and feed themselves within a few hours from hatching. They are cared for by both parents and brooded when small. The young fledge at around 35-42 days, but often remain dependent until well after fledging. Avocets are single brooded, but will lay again if the first clutch is lost before hatching. Chick survival can be poor, and is determined largely by weather and food supply.
Once breeding territory is established Avocets are highly aggressive against all birds, and fiercely protective of their young. The main factor regulating population size is competition for breeding space. Larger colonies tend to have a lower chick productivity per pair than smaller colonies.
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Our Very Own Avocets
For a number of years now Southend has been blessed with the Wonderful Avocet, the symbol of the RSPB. The main local areas for this lovely bird are Two Tree Island (west) and the Wakering area. Avocets have bred with varying degrees of success over the last few years at both of these locations.
By far the most successful breeding location has been Two Tree Island on the lagoon at the western end and we would very much appreciate any reports of chicks and adults from the Island if anyone is visiting. Hopefully with this information we will better understand the problems and conservation issues surrounding this most elegant of waders.
Remember these are our birds, let's be proud of them and protect them!
Avocet Information
Avocets are typically gregarious much of the year. Outside the breeding season the birds are usually in flocks of 6-30 individuals, but feeding flocks in certain conditions can be several hundred strong. Flocks break up for the duration of the breeding season. Summer flocks consist at first of immature non-breeders, later joined by failed breeders and then adults with fledged young.
The mating behaviour of Avocets is very elegant. Initially both birds can be seen preening vigorously, then the female lowers her head, stretches it low over the water and stands almost motionless. The male continues to preen excitedly, frequently dipping his bill in the water and moving first to one side of her and then the other, switching sides many times by walking behind her (if he passes in front copulation is unlikely to take place). Eventually he jumps sideways onto her back and with wings spread and bill open sinks down onto his tarsi whilst she swings her head from side to side. After copulation the male drops sideways into the water and the pair run forward with bills crossed, the male with one wing over the females back. Finally they run away from each other in a hunched posture.
Avocets feed by wading in the shallow water at the edge of a lagoon or in tidal mud. In deeper water they swim readily and buoyantly, up-ending like a duck to reach food below the surface. At times large feeding flocks will assemble - sometimes several hundred strong - to feed co-operatively on items such as shrimps on the edge of a rising tide.
The primary food is invertebrates, especially crustaceans and worms and in fresh water also insects, which are found on the surface or within the top layers of the bottom sediments.
There are two feeding methods. In clear water Avocets feed by sight by picking prey from the surface of water or mud. In poor visibility and when locating prey from within the sediments they forage by touch, and the birds sweep the long, upcurved bill from side to side through water or loose sediment to locate hidden prey. A large range of food items has been recorded, but the diet comprises those species that are most available and abundant.
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Avocets and the Law
The Avocet is listed on Schedule 1 of the Wildlife & Countryside Act 1981, which affords special protection at all times. It is an offence to take, injure or kill an Avocet or to take, damage or destroy its nest, eggs or young. It is also an offence to intentionally or wrecklessly disturb the birds at or close to their nest during the breeding season. Violation of the law can attract fines up to 5,000 per offence and/or a prison sentence of up to 6 months.
History of the Avocet
The species declined in north-west Europe in the 19th century largely due to habitat loss, hunting and egg-collecting. It became extinct as a breeding species in Britain in 1842, and also in Sweden. Both countries were re-colonised early this century, and the breeding numbers along the North Sea increased from 1,800 pairs in 1924 to 16,400-19,700 pairs in the 1980s. This is thought to be related to better protection, extension of breeding habitat and improvement in feeding conditions. The increase in the British population is related to habitat creation and management. Unfortunately, large declines have been reported in the east and south-east European populations since 1970.
In the UK, the Avocet used to breed widely in the marshes and fens of east and south-east England from Humber to Kent, but became extinct as a breeding bird in 1842 as a result of extensive land claim and the building of sea walls. Flooding for military defences during the 1939-1945 created ideal conditions for the Avocets, and they returned to breed at Minsmere and on Havergate Island in 1947. Both these sites were acquired by the RSPB for the conservation of the Avocet, and the breeding numbers have since steadily increased on both these reserves and elsewhere. Since the mid-1970s there has been a considerable range expansion and population increase.
Threats and Conservation
The main threats facing the Avocet throughout Europe are loss and disturbance of breeding habitat, and the deterioration of feeding conditions at breeding and wintering sites. Egg and chick predation can be significant in some breeding colonies.
Small numbers winter along the North Sea coast, but over 90% of the birds wintering in Europe are concentrated in southern Europe at just 10 sites, making the species highly vulnerable to habitat loss or degradation. Many of the coastal wetlands used are under considerable pressure from land-claim, pollution, marine farming and disturbance.
Conservation of the Avocet depends primarily on protection and proper management of their main breeding and wintering sites across Europe. In the UK most of the birds breed within reserves, where the management of brackish lagoons is tailored to the requirements of the species. Protection of wintering birds on estuaries such as the Exe requires the involvement of other organisations and private individuals and forms a part of broader scale estuary conservation and management plans. Elsewhere in Europe many of the coastal wetlands where Avocets concentrate in winter are under considerable pressure from land-claim, pollution, marine farming and disturbance. Protection of these sites is of primary importance.
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Avocet Facts
Avocets usually nest close together in colonies. The nest is a shallow hollow in the mud, lined with a few pebbles or pieces of shell. Four eggs are laid and incubated by both adults for just over three weeks. Like all young waders, the chicks are active from hatching and the adults defend a feeding territory around them, chasing off other Avocets and even birds as large as mute swans and spoonbills!
Being large and conspicuous, Avocets believe that 'attack is the best form of defence' and will try to chase off potential predators, be they crows, gulls or foxes. But a colony of Avocets is like a supermarket to a fox, lots of food in a small area and all easy to catch! Therefore at some sites nesting areas are protected with electric fences.
The avocets diet consists mainly of aquatic insects and their larvae, crustaceans and worms.
The avocet makes a fluty 'kloot' and a yelping 'kleep, kleep...'
Did You Know?
The Avocet is also known as a cobblers awl due to the shape of its beak, which resembles a shoemakers tool!
  Photos by Steve Arlow, Southend Ornithological Group |
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