The protection of the species implies the preservation of the ecosystem, and the education of people, to respect and protect these large birds, often mentioned in mythology, legends and traditions.
Text by Nicole Bouglouan
José Luis Beamonte: Pájaros de España
Didier Buysse: Vision d’Oiseaux
Jean Michel Fenerole: Photos d’Oiseaux
Steve Garvie: RAINBIRDER Photo galleries
Tom Grey: Tom Grey's Bird Pictures
Patrick Ingremeau: TAMANDUA
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David Nowell: Virtually Home - PHOTO GALLERY
Yves Thonnerieux: NATUR’AILES
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Philippe Wolfer: OISEAUX D’ARGENTINE
Nicole Bouglouan: PHOTOGRAPHIC RAMBLE
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
THE HANDBOOK OF BIRD IDENTIFICATION FOR EUROPE AND THE WESTERN PALEARCTIC by Mark Beaman, Steve Madge - C.Helm - ISBN: 0713639601
BIRDS OF AFRICA SOUTH OF THE SAHARA by Ian Sinclair and Peter Ryan - Princeton University Press Princeton and Oxford - ISBN: 0691118159
ROBERTS BIRDS OF SOUTH AFRICA by G. R. Mc Lachlan and R. Liversidge – The Trustees of the John Voelcker Bird Book Fuund – ISBN: 0620031182
Wood Storks, Openbills and Storks
The Family Ciconiidae belongs to the Order Ciconiiformes, and includes 19 species within six different genera.
Medium-sized to large wading birds, they have long bill, neck and legs, indicating their preference for wet habitats, even if some of them frequent mainly grassy or forested areas.
All species have almost similar appearance with relatively heavy and large body. The largest member of the family, the Marabou (Leptoptilos crumeniferus) is about 152 cm tall and can weight 8-9 Kg. For comparison, the Abdim’s Stork (Ciconia abdimii) only measures 75-80 cm and weights 1-3 Kg.
Both sexes have similar plumage, but the male is usually slightly larger than the female.
They usually are black and white with some variations such as the Painted Stork and the Yellow-billed Stork with the wings showing pinkish feathers.
We also can see some glossy green or purple feathers on neck, wings or back of the birds of the genus Ciconia.
In all species, the juveniles are duller and greyer or browner than adults.
The bill is the most interesting criterion of this family. It is always large, and can be really huge in some species such as the Marabou which beak grows continuously until to reach about 34-35 cm long.
There are variable shapes according to the feeding behaviour.
The seven birds of genus Ciconia have medium to large bill, fairly pointed and straight. This tool is well adapted for the different kinds of preys taken in varied types of habitats.
Some of them show bare skin on the face, or broad bright eye-ring.
The two members of genus Ephippiorhynchus and that of Jabiru have longer bills, pointed and slightly upturned, adapted for jabbing at fish in shallow water.
The Jabiru has the largest of the three species. Head and neck are covered with bare black skin, with bright red collar at neck base.
The Saddlebill has bright coloured bill with red and black mandibles and yellow shield at upper bill base.
The Black-necked Stork male has dark brown iris, whereas female has yellow eyes, which is unique among storks where male and female are always similar.
The three “giant” storks of genus Leptoptilos have huge bill, used as weapon to kill larger preys. The Marabou is known for killing and eating adult and young flamingos. Face and neck are not feathered and covered with reddish bare skin.
The four birds of genus Mycteria have long, tapered and slightly decurved bill with sensitive parts at the tip, adapted for feeding in muddy water. The bare coloured skin of the face becomes brighter during the breeding season.
The two members of genus Anastomus share the most unusual bill. An opening between the mandibles gives it deformed appearance. But this type of beak is a good tool for the restricted diet of these birds, the apple snails of genus Pila. The open bill shows a hollow in the lower mandible, a wide gap of several centimetres, allowing the bird to grip the shell of the snail. The tips are joined.
All species have long legs allowing them to forage in shallow water where they live and feed. They prefer and frequent several types of wetlands, but some species such as the Marabou which often scavenges around for carcasses in dry savannahs, and the Abdim’s Stork which is frequently seen in dry grasslands does not necessarily need water all year round.
However, these large birds often nest in trees and need at least some thickets or scattered trees in their preferred habitats, but the European White Stork can also nest on roofs of buildings, as the Abdim’s Stork which makes the nest in the roofs of native huts, but also on rocky islands and in dry uplands.
Other species such as the Yellow-billed Stork in West Africa and the Painted Stork in parts of India may nest sometimes in towns.
The Black Stork nests in fairly dense forest, or on cliff ledges in Spain, close to the Griffon Vultures and the Egyptian Vultures.
The Maguari Stork from South America is the only stork that nests on flat ground and often in reedbed in marshy area.
All the members of the Family Ciconiidae are carnivorous and their typical food includes small fish, frogs, insects and small rodents, but according to the species, the size and the preys can change.
In the genus Mycteria, the Wood Stork can take salamanders, small snakes and even young caimans. These species feed usually in shallow muddy water by moving the submerged bill from side to side and walking slowly. The sensitive parts of the bill tip allow the bird to catch the prey as soon as it comes into contact with it.
The openbills feeds almost exclusively on freshwater molluscs, and especially the apple snails Pila, and some frogs and crabs. They often feed in small groups and dig around into the muddy water of marshes and ricefields.
The other members of Ciconiidae have more generalized feeding methods. They are opportunists, taking all available food at any time such as small fish, amphibians, snakes, small mammals and insects.
However, the Abdim’s Stork can be classified as specialist feeder, eating a high proportion of insects, often at grass fires or around swarms of locusts, like the European White Stork in its wintering grounds in Africa.
They forage by walking slowly in shallow water or dry grassland, and looking out for food. When the prey is located by sight, the neck is stretched before to jab and grasp the prey with the bill.
The Black-necked Stork, the Saddlebill and the Jabiru have similar feeding habits, but the Jabiru is also known to take young alligators, snakes and turtles.
These species forage in shallow water, but also in grassland or open woodland. They usually feed alone or in pairs, but the Jabiru can be seen with other Ciconiiformes or several birds feeding by walking side to side in communal fishing.
The Greater Adjutant and the Marabou have different feeding behaviour, and take mainly carrion, feeding on dead animals and obtaining waste food and refuse from humans. But they also feed like the other storks, taking fish, amphibians and crustaceans. The Marabou is a predator for the flamingos, taking as well eggs and chicks as adults which may be killed.
The Lesser Adjutant seems to take mainly mudskippers (Periophthalmus). They forage along the edge of the sea, at about 50 metres from each other, jabbing the bill repeatedly into the mud.
The feeding behaviour of the Ciconiidae is relatively similar for all the species, with some variations according to the bill’s shape and the range.
Several species are colonial breeders, with loose or dense colonies which can range from 5-15 pairs in Maguari Storks, to several thousands in Abdim’s Stork and members of Leptoptilos, Mycteria and Anastomus genera. Other species breed in mixed colonies with pelicans and Ardeidae species. But these same species can also be solitary nesters.
Some species such as the members of genera Jabiru and Ephippiorhynchus, and the Black Stork, the Wooly-necked Stork and the Storm’s Stork are exclusively solitary nesters.
The breeding period is seasonal in all species, and closely related to water which involves food availability.
Most species nest in trees, often at good height. The birds tend to reuse the same nest-site for successive years. Marabous can use the same colony for over 50 years.
Usually, the male arrives first and starts to defend the small territory. In Maguari Storks, the defence is very strong, and the fights may become violent. Once the territories are occupied by the males, the females arrive and try to approach, but often receive the same aggression before to appease the selected male.
Various ritual displays occur, such as greeting ceremonies, with the most used and called “Up-down”. When one bird returns to the nest, the other raises and lowers the head, and produces some sounds, usually bill-clattering. This display is also used as threat against intruders. It may be slightly different according to the species.
Other displays such as the “Advertising sway” with male rocking from one foot to other with head held down between the legs, is performed by the openbills.
Several other displays occur in each species, and are used as well on the feeding grounds as at nest-site where all are associated with confirmation of pair-bonds.
The solitary breeders have less elaborate courtship rituals, due to the lack of competition. The mates often form permanent pair, whereas the colonial breeders can form a new pair every year.
Once the pair is formed, the nest is built or repaired. The birds add new material brought by the male and put in place by the female. The nest is made with sticks, and the cup is sometimes lined with softer material.
Some huge nests, such as those of the European White Stork, are used by other species, Passer (sparrows), Sturnus (starlings) and even Coracias (rollers), according to the location. The Jabirus’ nests also attract several opportunists which help to make the structure more solid by adding mud and other materials.
During the nest building, copulation is frequent and often performed on the nest. The eggs are laid within a week after the first copulation, at two days intervals.
The female lays three to five eggs, even up to seven in the European White Stork. On the other hand, the Saddlebill only lays one single egg. Often oval and creamy-white, the extreme sizes are 84 x 60 mm for 145 grams in Marabou, whereas the Abdim’s Stork has smaller eggs, 54 x 45 mm for 58 grams.
The incubation is usually shared by both parents and lasts from 25 to 38 days, according to the species. The chicks are nidicolous, but very soon, they are covered in whitish down, except those of the Maguari Stork which are blackish for better camouflage on the ground.
They are fed by both adults by regurgitation into the nest, making the smallest chick able to feed too.
They fledge at about 50 days in the smaller species, but the Marabou’s chicks need probably up to 100 days. They depend on parents for some weeks and return to the nest to roost at night. They can breed between 3 and 5 years of age.
Storks are usually silent, but they can produce some vocalizations and noises at the breeding areas.
The display “Up-down” is often accompanied with bill clattering. But other sounds can be heard, such as hisses in Mycteria, honk or croak in Anastomus, and squeals and moos in Leptoptilos.
Other storks are more silent, only producing some bill clattering, in courtship or threat displays. The openbills are not able to give sounds due to their open bill. But the Marabou is “highly” vocal, giving moos, whines, whistles, both in courtship and threat displays. Its young are able to produce several kinds of sounds at different ages.
Storks are more or less migratory. The two European species, the White and the Black Storks migrate every year to reach warmer areas in winter.
But few storks are really migratory, even if they perform several kinds of movements and local or nomadic dispersions.
The local dispersions are associated to the food resources, and some birds have to travel over long distances between the nest-site and the feeding areas.
Wood Storks have been observed feeding at about 130 km from their colony.
The solitary Saddlebill seems to be sedentary, only moving around in the surroundings for best food.
Both openbill species perform regular movements not yet well understood, as the movements of the Oriental White Stork.
The Abdim’s Stork is a true tropical migrant, following the rains which provide abundant insects.
The species often travel in large flocks. The storks take advantage of the thermal currents and often soar and glide during the movements and migrations. They do not like to cross large water bodies, and for the European birds, the Mediterranean which separates their African wintering grounds from their European breeding areas is a problem. They prefer to use the route crossing points at the Straits of Gibraltar and the Bosporus where great concentrations of migrating species regularly occur.
They also have to cross the desert and they fly straight across the Sahara without stopover. But usually, they tend to drop down in grasslands to feed every day.
The Ciconiidae species occur in all continents except the Antarctic and the most parts of North America. They are more numerous in tropical regions.
Due to their presence in several legends and traditions, storks are relatively well protected and loved. However, several threats are mentioned, even if the colonies seem to be large.
The Asian Openbill is the victim of its great reproductive success. Within the sanctuary where they breed, the trees where the colonies are established are dying, and going outside these areas expose the birds to several threats and hunting.
Some species have suffered human exploitation, with consumption of the chicks after to be fattened. The Milky Stork and the Lesser Adjutant in eastern Sumatra, and the Maguari Stork in Venezuela are threatened.
The species currently threatened belong to Asia, and occur in overpopulated regions. The populations of the Greater Adjutant have dramatically decreased due to guerrillas, poaching, hunting, destruction of nesting trees and degradation of the feeding grounds, making the area devastated.
All the species are currently in decline, more or less according to the species. During the migrations through Africa, many birds are killed by hunters.
The intensification of agriculture involves the restriction of the feeding areas, and the level of pollution are increasing, affecting the preferred preys of these birds.
In South America, destruction and reconversion of large areas threaten the Maguari Stork in the llanos of Venezuela.
The main threats are always the same, with habitat loss, destruction of large nesting trees, pollution, intensification of agriculture, poaching, hunting…
These birds are very useful as pest control, feeding on insects and rodents, and for some species, cleaning the nature by eating at carcasses.