Colours of Wildlife: Avocet

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Avocet

Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"

Avocet by Willem.


We're back to the front of the alphabet! This is the Avocet, Recurvirostra avosetta. It's scientific name means 'Avocet with a recurved bill'. I don't know what 'avocet' means … the name seems to be ancient and to come from the original Latin name for the bird. It is sometimes also called the Pied Avocet, for its bold black-and-white markings.


This species of avocet occurs in Africa, Europe and most of Asia. Related species occur in North and South America. Avocets are closely related to stilts. Like them, they are medium-sized, long-legged waders. They differ from stilts in that their bills are not straight, but turned up at the tips.

Bill like an Awl


As mentioned in the above article, stilts as well as avocets are called 'Elsies' in Afrikaans, meaning 'little awls', for their thin, sharp bills. In the avocet's case, it's a bent awl. What is the use of an apparently maimed bill like this? Well, the avocet, like the flamingos, feeds on very small water critters. While the flamingo feeds with its head almost straight down, the avocet feeds with its head down only at a shallow angle. The forward-curvature of its bill's tip thus actually brings the front of the bill to a position level with the water surface. Also unlike flamingos, who have fine comb-like filters in their bills, the avocet doesn't filter out the food items, but grabs them individually in its bill. It must therefore have a very delicate sense of touch! Food for the avocets include brine shrimps, tiny fish fry, worms and other very small aquatic invertebrates. They wade in the water, using their long legs to go in quite deep, while sweeping their heads from side to side with the front of the bill just under the water surface, very rapidly grabbing any food item they sense. Avocets also have toes that are halfway webbed, so that they can occasionally even venture into deeper water, floating like ducks and paddling themselves forward.

Curious Movements


Although avocets occur over a very large range spanning several continents, they aren't resident everywhere. In the northern parts of Europe and Asia, they are migratory, heading south as soon as the northern winter arrives. Here in Africa, the seasons don't affect them as much, it mainly being a matter of where, and when, water is present. They prefer fairly shallow water, as well as water that is salty, since this is the environment for their favourite food, brine shrimps. They are particularly associated with seasonal pans, of which many occur in the dry interior of Southern Africa, like the Makgadikgadi or the Etosha Pans of Botswana and Namibia. These pans are dry most of the time, but in years of good rains become huge, though mostly shallow, expanses of water, providing feeding and nesting grounds for vast numbers of waders. While avocets prefer these big pans, where they converge to breed in large numbers in years of good rains, they also breed at smaller inland pans and waterbodies. In dry years, however, they tend to stay along the coast, where they breed in coastal lagoons and estuaries.


Avocet movements are quite complex, therefore; in northern Africa, many avocets are migratory, commuting between Europe, Asia and Africa, while in sub-Saharan Africa, they are mostly resident in particular areas, broadly conceived, but move around a lot in response to rainfall patterns. I still wonder how birds on the coast know that there have been good rains deep inland, so that they can head off to their favourite pans!

Avocet Babies


The breeding season for avocets therefore depend on the rains. In most of Southern Africa, rains fall during Spring and Summer, but in dry regions, this pattern is erratic, and in some years, hardly any rain falls at all. Here therefore, it's not often possible to predict where and when avocets will breed. In the Southwestern Cape, however, rainfall predictably occurs in the winter and here the avocets have fixed breeding grounds and times.

At the onset of the breeding season, avocets perform unusual group displays. In a region where many couples are present, they all gather in a circle, and perform ritualized bowing to each other. Then they move out couple-by-couple, each finding a good place to nest. The male and female also perform a kind of nest-scraping ritual to each other, before starting the actual nests. They may start and abandon several nest sites before deciding on one they'll keep.


Whether breeding in summer or winter, avocets tend to breed towards the end of the season, when the water is retreating. This is to ensure that their nests don't get flooded! They build their nests sometimes in wet ground, sometimes in dry, far away from the waterline. If on dry land, the nest is a hollow scraped out and lined with bits of vegetation; in a wet patch, it is built up into a tall mound so that the eggs stay dry. Avocet eggs are olive greenish with darker mottling, quite well-camouflaged; nests and eggs are not easily distinguished from piles and tangles of vegetation. The clutch size ranges from three to five.


Both the male and female incubate the eggs, taking shifts of around an hour each. They'll try to distract predators from the nests, by feigning injury, similar to how some plovers and lapwings do it. The chicks hatch after about 24 days. When hatching starts, the parents anxiously remove the pieces of eggshell, dropping some far away, even swallowing some of the smaller pieces themselves. Baby avocets hatch with open eyes and are covered in fluff, greyish with some black markings on their backs. They already have bills that are slightly upturned. Sometimes the parents will carry these young chicks around, tucked in under their wings with just their feet sticking out! But the chicks can walk, run and swim well on their own. They accompany their parents, who show them how to feed and survive. At the age of about a month, they're able to fly.


Avocets are not in danger of extinction at present, occurring over a very wide range as they do. Yet, they are not particularly common everywhere, and here in Southern Africa, they number perhaps about ten to twenty thousand. They are fairly dependent on large, pristine wetland regions for their survival. But they've actually benefited from the many man-made lakes, ponds, sewage treatment plants and salt works.

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