I walk by a house with a giant balloon stork welcoming new baby Parker. At least this celebration of new life is harmless compared to some of the incendiary devices used for gender reveal parties. But, it did make me wonder about storks. I don’t think I have ever seen one. I’ve seen blue herons and egrets, but no storks. Do they exist only in our imaginations? Apparently not, according to Wikipedia. They are real. To find out more, read on.
The white stork is a large bird in the stork family, Ciconiidae. Its plumage is mainly white, with black on the bird's wings. Adults have long red legs and long pointed red beaks, and measure on average 39–45 inches from beak tip to end of tail, with a 61–85 inch wingspan. The two subscpecies, which differ slightly in size, breed in Europe (north to Finland), northwestern Africa, southwestern Asia (east to southern Kazakhstan) and southern Africa. The white stork is a long-distance migrant, wintering in Africa from tropical Sub-Saharan Africa to as far south as South Africa, or on the Indian subcontinent. When migrating between Europe and Africa, it avoids crossing the Mediterranean Sea and detours via the Levant in the east or the Strait of Gibraltar in the west, because the air thermals on which it depends for soaring do not form over water.
A carnivore, the white stork eats a wide range of animal prey, including insects, fish, amphibians, reptiles, small mammals and small birds. It takes most of its food from the ground, among low vegetation, and from shallow water. It is a monogamous breeder, but does not pair for life. Both members of the pair build a large stick nest, which may be used for several years. Each year the female can lay one clutch of usually four eggs, which hatch asynchronously 33–34 days after being laid. Both parents take turns incubating the eggs and both feed the young. The young leave the nest 58–64 days after hatching and continue to be fed by the parents for a further 7–20 days.
The white stork benefited from human activities during the Middle Ages as woodland was cleared, but changes in farming methods and industrialization saw it decline and disappear from parts of Europe in the 19th and early 20th centuries. Conservation and reintroduction programs across Europe have resulted in the white stork resuming breeding in the Netherlands, Belgium, Switzerland, Sweden and the United Kingdom. It has few natural predators, but may harbor several types of parasite; the plumage is home to chewing lice and feather mites, while the large nests maintain a diverse range of mesostigmatic mites.
Etymology
Both the genus and specific epithet, cĭcōnia, are the Latin word for "stork," originally recorded in the works of Horace and Ovid. The Latin word survives in most Romance languages. The word “stork” is derived from the Old English word “storc,” and appeared in the 10th-century works the “Erfurt Glossary.” The word is related to the Old High German “storah” or "stork."
Taxonomy
The stork family contains six genera in three broad groups: the open-billed and wood storks (Mycteria and Anastomus), the giant storks (Ephippiorhynchus, Jabiru and Leptoptilos), and the "typical" storks, Ciconia which include the white stork and six other extant species, which are characterized by straight pointed beaks and mainly black and white plumage.
Description
As with other storks, the wings are long and broad enabling the bird to soar. In flapping flight, its wingbeats are slow and regular. It flies with its neck stretched forward and with its long legs extended well beyond the end of its short tail. It walks at a slow and steady pace with its neck upstretched. In contrast, it often hunches its head between its shoulders when resting. Molting has not been extensively studied, but appears to take place throughout the year, with the primary flight feathers replaced over the breeding season.
Upon hatching, the young white stork is partly covered with short, sparse, whitish down feathers. This early down is replaced about a week later with a denser coat of woolly white down. By three weeks, the young bird acquires black scapulars and flight feathers. On hatching the chick has pinkish legs, which turn to greyish-black as it ages. Its beak is black with a brownish tip. By the time it fledges, the juvenile bird's plumage is similar to that of the adult, though its black feathers are often tinged with brown, and its beak and legs are a duller brownish-red or orange. The beak is typically orange or red with a darker tip. The bills gain the adults' red color the following summer, although the black tips persist in some individuals. Young storks adopt adult plumage by their second summer.
Similar species
Within its range the white stork is distinctive when seen on the ground. The winter range of C. c. asiatica overlaps that of the Asian openbill, which has similar plumage but a different bill shape. When seen at a distance in flight, the white stork can be confused with several other species with similar underwing patterns, such as the yellow-billed stork, great white pelican and Egyptian vulture. The yellow-billed stork is identified by its black tail and a longer, slightly curved, yellow beak. The white stork also tends to be larger than the yellow-billed stork. The great white pelican has short legs which do not extend beyond its tail, and it flies with its neck retracted, keeping its head near to its stocky body, giving it a different flight profile. Pelicans also behave differently, soaring in orderly, synchronized flocks rather than in disorganized groups of individuals as the white stork does. The Egyptian vulture is much smaller, with a long wedge-shaped tail, shorter legs and a small, yellow-tinged head on a short neck. The common crane, which can also look black and white in strong light, shows longer legs and a longer neck in flight.
Habitat
The white stork's preferred feeding grounds are grassy meadows, farmland and shallow wetlands. It avoids areas overgrown with tall grass and shrubs. In the Chernobyl area of northern Ukraine, white stork populations declined after the 1986 nuclear accident there as farmland was succeeded by tall grass shrubs. In parts of Poland, poor natural foraging grounds have forced birds to seek food at rubbish dumps since 1999. White storks have also been reported foraging in rubbish dumps in the Middle East, North Africa and South Africa.
The white stork breeds in greater numbers in areas with open grasslands, particularly grassy areas which are wet or periodically flooded, and less in areas with taller vegetation cover such as forest and shrubland. They make use of grasslands, wetlands, and farmland on the wintering grounds in Africa. White storks were probably aided by human activities during the Middle Ages as woodland was cleared and new pastures and farmland were created, and they were found across much of Europe, breeding as far north as Sweden. The population in Sweden is thought to have established in the 16th century after forests were cut down for agriculture. About 5,000 pairs were estimated to breed in the 18th century which declined subsequently. The first accurate census in 1917 found 25 pairs and the last pair failed to breed around 1955. The white stork has been a rare visitor to the British Isles, with about 20 birds seen in Britain every year, and prior to 2020 there were no records of nesting since a pair nested atop St Giles High Kirk in Edinburgh, Scotland in 1416. In 2020, a pair bred in the United Kingdom for the first time in over 600 years, as part of an re-introduction initiative called the White Stork Project.
A decline in population began in the 19th century due to industrialization and changes in agricultural methods. White storks no longer nest in many countries, and the current strongholds of the western population are in Portugal, Spain, Ukraine and Poland. In the Iberian Peninsula, populations are concentrated in the southwest, and have also declined due to agricultural practices. A study published in 2005 found that the Podhale region in the uplands of southern Poland had seen an influx of white storks, which first bred there in 1931 and have nested at progressively higher altitudes since, reaching 3,000 feet in 1999. White storks arriving in Poznań province (Greater Poland Voicodeship) in western Poland in spring to breed did so some 10 days earlier in the last twenty years of the 20th century than at the end of the 19th century.
Migration
Systematic research into migration of the white stork began with German ornithologist Johannes Thienemann who commenced bird ringing studies in 1906 at the Rossitten Bird Observatory, on the Curonian Spit in what was then East Prussia. Although not many storks passed through Rossitten itself, the observatory coordinated the large-scale ringing of the species throughout Germany and elsewhere in Europe. Between 1906 and the Second World War about 100,000, mainly juvenile, white storks were ringed, with over 2,000 long-distance recoveries of birds wearing Rossitten rings reported between 1908 and 1954.
Routes
White storks fly south from their summer breeding grounds in Europe in August and September, heading for Africa. There, they spend the winter in savannah from Kenya and Uganda south to the Cape Province of South Africa. In these areas they congregate in large flocks which may exceed a thousand individuals. Some diverge westwards into western Sudan and Chad, and may reach Nigeria. In spring, the birds return north; they are recorded from Sudan and Egypt from February to April. They arrive back in Europe around late March and April, after an average journey of 49 days. By comparison, the autumn journey is completed in about 26 days. Tailwinds and scarcity of food and water en route (birds fly faster over regions lacking resources) increase average speed.
Juvenile white storks set off on their first southward migration in an inherited direction but, if displaced from that bearing by weather conditions, they are unable to compensate, and may end up in a new wintering location. Adults can compensate for strong winds and adjust their direction to finish at their normal winter sites, because they are familiar with the location. For the same reason, all spring migrants, even those from displaced wintering locations, can find their way back to the traditional breeding sites. An experiment with young birds raised in captivity in Kaliningrad and released in the absence of wild storks to show them the way revealed that they appeared to have an instinct to fly south, although the scatter in direction was large.
Energetics
White storks rely on the uplift of air thermals to soar and glide the long distances of their annual migrations between Europe and Sub-Saharan Africa. For many, the shortest route would take them over the Mediterranean Sea; however, since air thermals do not form over water, they generally detour over land to avoid the trans-Mediterranean flights that would require prolonged energetic wing flapping. It has been estimated that flapping flight metabolizes 23 times more body fat than soaring flight per distance travelled. Thus, flocks spiral upwards on rising warm air until they emerge at the top, up to 3,900–4,900 feet above the ground (though one record from Western Sudan observed an altitude of 10,800 feet.
Long flights over water may occasionally be undertaken. A young white stork ringed at the nest in Denmark subsequently appeared in England, where it spent some days before moving on. It was later seen flying over St Mary’s, Isles of Scilly, and arrived in a poor condition in Madeira three days later. That island is 320 miles from Africa, and twice as far from the European mainland. Migration through the Middle East may be hampered by the khamsin, winds bringing gusty overcast days unsuitable for flying. In these situations, flocks of white storks sit out the adverse weather on the ground, standing and facing into the wind.
Behavior
The white stork is a gregarious bird; flocks of thousands of individuals have been recorded on migration routes and at wintering areas in Africa. Non-breeding birds gather in groups of 40 or 50 during the breeding season. The smaller dark-plumaged Abdim’s stork is often encountered with white stork flocks in southern Africa. Breeding pairs of white storks may gather in small groups to hunt, and colony nesting has been recorded in some areas. However, groups among white stork colonies vary widely in size and the social structure is loosely defined; young breeding storks are often restricted to peripheral nests, while older storks attain higher breeding success while occupying the better quality nests toward the centers of breeding colonies. Social structure and group cohesion are maintained by altruistic behaviors such as allopreening. White storks exhibit this behavior exclusively at the nest site. Standing birds preen the heads of sitting birds, sometimes these are parents grooming juveniles, and sometimes juveniles preen each other. Unlike most storks, it never adopts a spread-winged posture, though it is known to droop its wings (holding them away from its body with the primary feathers pointing downwards) when its plumage is wet.
A white stork's droppings, containing faeces and uric acid, are sometimes directed onto its own legs, making them appear white. The resulting evaporation provides cooling and is termed urohidrosis. Birds that have been ringed can sometimes be affected by the accumulation of droppings around the ring leading to constriction and leg trauma. The white stork has also been noted for tool use by squeezing moss in the beak to drip water into the mouths of its chicks.
Communication
The adult white stork's main sound is noisy bill-clattering, which has been likened to distant machine gun fire. The bird makes these sounds by rapidly opening and closing its beak so that a knocking sound is made each time its beak closes. The clattering is amplified by its throat pouch, which acts as a resonator. Used in a variety of social interactions, bill-clattering generally grows louder the longer it lasts, and takes on distinctive rhythms depending on the situation — for example, slower during copulation and briefer when given as an alarm call. The only vocal sound adult birds generate is a weak barely audible hiss; however, young birds can generate a harsh hiss, various cheeping sounds, and a cat-like mew they use to beg for food. Like the adults, young also clatter their beaks. The up-down display is used for a number of interactions with other members of the species. Here a stork quickly throws its head backwards so that its crown rests on its back before slowly bringing its head and neck forwards again, and this is repeated several times. The display is used as a greeting between birds, post coitus and also as a threat display. Breeding pairs are territorial over the summer, and use this display, as well as crouching forward with the tails cocked and wings extended.
Breeding
The white stork breeds in open farmland areas with access to marshy wetlands, building a large stick nest in trees, on buildings or on purpose-built man-made platforms. Each nest is 3.3–6.6 feet in depth, 2.6–4.9 feet in diameter and 130–550 lbs. in weight. Nests are built in loose colonies. Not persecuted as it is viewed as a good omen, it often nests close to human habitation; in southern Europe, nests can be seen on churches and other buildings. The nest is typically used year after year especially by older males. The males arrive earlier in the season and choose the nests. Larger nests are associated with greater numbers of young successfully fledged, and appear to be sought after. Nest change is often related to a change in the pairing and failure to raise young the previous year, and younger birds are more likely to change nesting sites. Although a pair may be found to occupy a nest, partners may change several times during the early stages and breeding activities begin only after a stable pairing is achieved.
Several bird species often nest within the large nests of the white stork. Regular occupants are house sparrows, tree sparrows and common starlings; less common residents include Eurasian kestrels, little owls, European rollers, white wagtails, black redstarts, Eurasian jackdaws and Spanish sparrows. Paired birds greet by engaging in up-down and head-shaking crouch displays and clattering the beak while throwing back the head.
A white stork pair raises a single brood a year. The female typically lays four eggs, though clutches of one to seven have been recorded. The eggs are white, but often look dirty or yellowish due to a glutinous covering. They typically measure 2.9 inches × 2.0 inches, and weigh 3.4–4.6 oz., of which about 0.39 oz. is shell. Incubation begins as soon as the first egg is laid, so the brood hatches asynchronously, beginning 33 to 34 days later. The first hatchling typically has a competitive edge over the others. While stronger chicks are not aggressive towards weaker siblings, as is the case in some species, weak or small chicks are sometimes killed by their parents. This behavior occurs in times of food shortage to reduce brood size and hence increase the chance of survival of the remaining nestlings. White stork nestlings do not attack each other, and their parents' method of feeding them (disgorging large amounts of food at once) means that stronger siblings cannot outcompete weaker ones for food directly, hence parental infanticide is an efficient way of reducing brood size. This behavior has not commonly been observed.
Cultural associations
Due to its large size, predation on vermin, and nesting behavior close to human settlements and on rooftops, the white stork has an imposing presence that has influenced human culture and folklore. The Hebrew word for the white stork is chasidah (חסידה), meaning "merciful" or "kind". Greek and Roman mythology portray storks as models of parental devotion. The third century Roman writer Aelian — citing the authority of Alexander of Myndus — noted in his De natura animalium (book 3, chapter 23) that aged storks flew away to oceanic islands where they were transformed into humans as a reward for their piety towards their parents. The bird is featured in at least three of Aesop’s Fables: The Fox and the Stork, The Farmer and the Stork and The Frogs Who Desired a King. Storks were also thought to care for their aged parents, feeding them and even transporting them, and children's books depicted them as a model of filial values. A Greek law called Pelargonia, from the Ancient Greek word pelargos for stork, required citizens to take care of their aged parents. The Greeks also held that killing a stork could be punished with death. Storks were allegedly protected in Ancient Thessaly as they hunted snakes, and widely held to be Virgil’s "white bird." Roman writers noted the white stork's arrival in spring, which alerted farmers to plant their vines.
Followers of Islam revered storks because they made an annual pilgrimage to Mecca on their migration. Some of the earliest understanding on bird migration were initiated by an interest in white storks; Pfeilstörche ("arrow storks") were found in Europe with African arrows embedded in their bodies. A well-known example of such a stork found in the summer of 1822 in the German town of Klütz in Mecklenburg was made into a mounted taxidermy specimen, complete with the ornate African arrow, that is now in the University of Rostock.
Storks have little fear of humans if not disturbed, and often nest on buildings in Europe. In Germany, the presence of a nest on a house was believed to protect against fires. They were also protected because of the belief that their souls were human. German and Dutch households would encourage storks to nest on houses, sometimes by constructing purpose-built high platforms, to bring good luck. Poles, Lithuanians, Ukrainians and Belarusians believe that storks bring harmony to a family on whose property they nest.
The white stork is a popular motif on postage stamps, and it is featured on more than 120 stamps issued by more than 60 stamp-issuing entities. It is the national bird of Lithuania, Belarus and Poland, and it was a Polish mascot at the Expo 2000 Fair in Hanover. Storks nesting in Polish villages such as Zywkowo have made them tourist attractions, drawing 2,000–5,000 visitors a year in 2014. In the 19th century, storks were also thought to only live in countries having a republican form of government. Polish poet Cyprian Kamil Norwid mentioned storks in his poem Moja piosnka (II) ("My Song (II)"):
For the land where it's a great travesty To harm a stork's nest in a pear tree, For storks serve us all ... I am homesick, Lord! ...
— translated by Walter Whipple
In 1942 Heinrich Himmler sought to use storks to carry Nazi propaganda leaflets so as to win support from the Boers in South Africa. The idea for this "Storchbein-Propaganda" plan was a secret that was transmitted by Walter Schellenberg to be examined by the German ornithologist Ernst Schüz at the Rossiten bird observatory, who pointed out that the probability of finding marked storks in Africa was less than one percent, requiring 1,000 birds to transmit 10 leaflets successfully. The plan was then dropped.
Storks and delivery of babies
According to European folklore, the stork is responsible for bringing babies to new parents. The legend is very ancient, but was popularized by a 19th-century Hans Christian Andersen story called "The Storks." German folklore held that storks found babies in caves or marshes and brought them to households in a basket on their backs or held in their beaks. These caves contained adebarsteine or "stork stones." The babies would then be given to the mother or dropped down the chimney. Households would notify when they wanted children by placing sweets for the stork on the window sill. From there the folklore has spread around the world to the Philippines and countries in South America. Birthmarks on the back of the head of newborn baby are sometimes referred to as stork-bite.
In Slavic mythology and religion, storks were thought to carry unborn souls from Vyraj to Earth in spring and summer. Vyraj is a mythical place in Slavic mythology where "birds fly for the winter and souls go after death" that is sometimes identified with paradise. This belief still persists in the modern folk culture of many Slavic countries, in the simplified child story that "storks bring children into the world." Storks were seen by Early Slavs as bringing luck, and killing one would bring misfortune. A long-term study that showed a spurious correlation between the numbers of stork nests and human births is widely used in the teaching of basic statistics as an example to highlight that correlation does not necessarily indicate causation. The child-bringing myth has appeared in different forms in history. Children of African American slaves were sometimes told that white babies were brought by storks, while black babies were born from buzzard eggs.
Psychoanalyst Marvin Margolis suggests the enduring nature of the stork fable of the newborn is linked to its addressing a psychological need, in that it allays the discomfort of discussing sex and procreation with children. Birds have long been associated with the maternal symbols from pagan goddesses such as Juno to the Holy Ghost, and the stork may have been chosen for its white plumage (depicting purity), size (in that it is big enough to carry an infant) and flight at high altitude (likened to flying between Earth and Heaven). The fable and its relation to the internal world of the child have been discussed by Sigmund Freud and Carl Jung. In fact, Jung recalled being told the story himself upon the birth of his own sister. The traditional link with the newborn continues with their use in advertising for such products as diapers and baby announcements.
There were negative aspects to stork folklore as well; a Polish folk tale relates how God made the stork's plumage white, while the devil gave it black wings, imbuing it with both good and evil impulses. They were also associated with handicapped or stillborn babies in Germany, explained as the stork having dropped the baby en route to the household, or as revenge or punishment for past wrongdoing. A mother who was confined to bed around the time of childbirth was said to have been "bitten" by the stork. In Denmark, storks were said to toss a nestling off the nest and then an egg in successive years. In medieval England, storks were also associated with adultery, possibly inspired by their courtship rituals. Their preening and posture saw them linked with the attribute of self-conceit.
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