Stork

• 1. Introduction

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  Storks are large, long-legged wading birds of the family Ciconiidae, and among the twenty living species, the marabou stork carries a wingspan of 3.2 meters and can weigh up to 8 kilograms, tying the Andean condor for the widest wingspan of any living land bird. They build nests that can grow to over 2 meters across and 3 meters deep, reused year after year, and they communicate less through calls than by clattering their bills together at the nest. For centuries, popular belief has cast the stork as the picture of fidelity and devoted parenting, a bird gentle enough to deliver newborn babies in Western folklore. But how well does that reputation match what's actually known about how storks live, hunt, and raise their young? Why does a family of birds this large and this recognizable still carry so many scientific unknowns? And how did a 19th-century photograph album of storks in flight end up shaping the invention of the airplane?

• 2. A Body Built To Soar

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  A marabou stork stands 152 centimeters tall and can weigh 8.9 kilograms, while at the other end of the size range the Abdim's stork reaches only 75 centimeters and weighs just 1.3 kilograms. Storks resemble herons in their long legs and necks but carry a heavier, more thickset build, and males can run up to 15% larger than females in some species, such as the saddle-billed stork, with almost no other visible difference between the sexes. Bill shape tracks diet closely across the genera: the large bills of Ciconia storks are the least specialized, the upturned bills of the Ephippiorhynchus and the jabiru are built for hunting fish in shallow water, the massive daggers carried by the two adjutants and the marabou serve for feeding on carrion and fending off other scavengers, and the sensitive, downcurved bills of the Mycteria storks let them detect prey by touch in cloudy water. Strangest of all are the bills of the two openbill species, which gape open in the middle even when closed, an adaptation built specifically for extracting aquatic snails.

  It has long been reported that storks lack a syrinx and cannot vocalize, but that turns out to be false; they do have syrinxes, capable of producing sound, even though they rarely use them. Their syrinxes are described as "variably degenerate," with the syringeal membranes in some species sitting between tracheal rings or cartilage, an unusual arrangement otherwise found only in ovenbirds.

  Flight favors efficiency over speed. Storks rely on soaring and gliding, riding thermal air currents to conserve energy rather than flapping continuously, and Ottomar Anschütz's celebrated 1884 photograph album of storks in flight directly inspired the design of Otto Lilienthal's experimental gliders in the late 19th century, a line of research that fed forward into powered flight itself.

• 3. Where Storks Live

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  A stork's range stretches across nearly every continent except the poles, most of North America, and large stretches of Australia, with the greatest diversity concentrated in tropical Asia, home to eight breeding species, and sub-Saharan Africa, home to six. Only three species reach the New World at all: the wood stork, the maguari stork, and the jabiru, the tallest flying bird found anywhere in the Americas. Europe and western temperate Asia see just two species, the white stork and the black stork, while the Oriental stork reaches temperate East Asia and the black-necked stork is confined to Australasia.

  Habitat preference varies almost as widely as range. The Mycteria "wood storks" and the Anastomus openbills depend heavily on water and aquatic prey, while species such as the marabou and Abdim's stork forage instead across open grassland savannah. Preferred terrain includes flooded grasslands, light woodland, marshes, paddyfields, wet meadows, and the backwaters of rivers and ponds; several species favor shallow pools especially as lakes and rivers dry out, since the shrinking water concentrates prey and leaves it with less room to escape. In South Africa, woolly-necked storks have adapted so completely to artificial feeding that they now nest largely in garden trees beside swimming pools, and elsewhere species including the greater adjutant and the white stork have taken to feeding directly at landfill sites. A smaller set of species keeps to less typical ground: European black storks favor dense temperate forest, and Storm's stork seeks out rainforest in Southeast Asia. Most storks avoid the sea outright, with exceptions among the lesser adjutant, the milky stork, and the wood stork, all of which forage in mangroves, lagoons, and estuarine mudflats.

• 4. Long Journeys, Fast Strikes

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  The white stork, black stork, and Oriental stork all undertake long annual migrations each winter, and from Europe those routes bend around long stretches of open water, crossing the Straits of Gibraltar or swinging east across the Bosphorus and down through Israel and the Sinai. Studies of young birds kept from traveling alongside experienced adults have shown that these routes are at least partly learned rather than instinctive, unlike the innate migration patterns seen in passerine songbirds. The Abdim's stork migrates entirely within the tropics instead, breeding from Senegal to the Red Sea during the wet season before moving south to southern Africa, and wood storks have been recorded commuting as far as 130 kilometers from their breeding colony just to reach feeding grounds.

  Hunting itself runs on speed rather than pursuit. Storks typically wade or stand in shallow water with the bill held submerged, and when it makes contact with prey, the bill snaps shut in just 25 milliseconds, among the fastest reactions recorded in any vertebrate, distinguishing living prey from an inert branch by a mechanism still not fully understood. Openbills specialize even further, feeding almost exclusively on freshwater apple snails; African openbills sometimes ride on the backs of hippos while foraging, and once a snail is caught, the bird carries it to land, where the fine tip of its bill pries the shell open and a narcotic compound in its saliva relaxes the snail enough to simplify extraction. Ciconia storks and marabous, by contrast, feed as generalists, sometimes gathering in large flocks to descend on locust swarms or scavenge at wildfires, a habit that has earned white storks and Abdim's storks the nickname "grasshopper birds."

• 5. Nesting And Numbers

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  Breeding habits split storks into three rough categories. The jabiru, the Ephippiorhynchus storks, and several Ciconia species nest entirely alone, while the Mycteria storks, the Abdim's stork, the openbills, and the Leptoptilos storks breed in colonies that can range from a couple of pairs to several thousand birds, often alongside herons, egrets, pelicans, cormorants, and ibises. White storks, Oriental storks, and Maguari storks fall somewhere in between, nesting loosely within sight of one another but with little real interaction, and sometimes nesting entirely alone instead, for reasons that remain unclear. All twenty stork species were once assumed to be strictly monogamous, but that has proven only partly true, with some species showing regular extra-pair breeding even while remaining socially paired.

  Storks appear to have been distinct, and possibly already widespread, by the Oligocene epoch, having likely arisen during the Palaeogene period some 40 to 50 million years ago, with fossils of living genera documented back to the Middle Miocene, roughly 15 million years ago. No stork species or subspecies is known to have gone extinct in historic times, yet a systematic review of nearly 1,000 published papers found most species still lacking real scientific study, enough that researchers have suggested many should be reclassified as Data Deficient on the IUCN Red List rather than confidently assessed at all. A single Ciconia bone turned up in a rock shelter on the island of Réunion, likely carried there as food by early settlers rather than evidence of a resident population, since no known account otherwise mentions storks anywhere in the Mascarene Islands. Storks have rarely served as food themselves, though they occasionally appeared on medieval banquet tables, and may have been eaten in Ancient Egypt as well.

• 6. Naming A Rigid Bird

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  The word "stork" entered English in its current sense by at least the 12th century, descending from the Old English storc and, before that, a hypothesized Proto-Germanic root and ultimately the Proto-Indo-European sr̥ǵos. The name points to the bird's stiff, upright posture, a meaning it shares with the related English word "stark," itself descended from the Old English stearc. Individual species carry their own etymological stories: the jabiru takes its name from Tupí-Guaraní words meaning "that which has" and "swollen," a reference to its thick, swollen-looking neck; the marabou stork borrows its name from the Arabic murābiṭ, meaning holy man, reflecting the reverence once attached to the species; and the adjutants take their name from the military rank, a nod to their stiff, marching gait.

  Classifying the family has shifted with the evidence. A DNA study found that the herons, the shoebill and hamerkop, and the ibises and spoonbills, families once grouped alongside storks under Ciconiiformes, actually belong instead with the pelicans, in Pelecaniformes, leaving Ciconiidae as the sole remaining member of its old order. The word for a stork group has its own variety too: a gathering can be called either a muster of storks or a phalanx of storks.

• 7. The Bird That Brings Babies

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  European folklore casts the white stork as the bearer of newborn babies, a legend ancient in origin but popularized worldwide by an 1839 Hans Christian Andersen story titled "The Storks." German tradition held that storks found babies hidden in caves or marshes, called adebarsteine, or "stork stones," and carried them home in a basket or their beak, sometimes dropping the infant down the chimney; households wishing for a child would leave sweets out on the windowsill to invite one. The idea eventually spread as far as the Philippines and countries across South America, and the birthmark doctors call nevus flammeus nuchae still carries the nickname "stork bite" on the back of a newborn's head.

  The belief had a darker mirror image too. A Polish folktale explains the stork's black-and-white plumage by saying God gave it white feathers while the Devil added black wings, leaving the bird with both good and evil in its nature, and in Germany storks were sometimes blamed for delivering handicapped or stillborn infants, said to have dropped the baby en route as a form of punishment. In Denmark, storks were said to toss a nestling from the nest one year and an egg the next. Ancient cultures built their own reverence around the bird independent of infants entirely: in Ancient Egypt, saddle-billed storks represented the ba, the ancient conception of the soul, and Greek law, called Pelargonia after the Greek word pelargos for stork, actually required citizens to care for their aging parents, on pain of death for anyone who killed a stork. The Roman writer Aelian, in his 3rd-century De natura animalium, even claimed that aged storks flew off to distant oceanic islands to be transformed into humans as a reward for their devotion to their parents. Storks also turn up in Aesop's fable "The Fox and the Stork," where a fox and a stork trade dinner invitations designed so neither guest can actually eat, a story meant to warn readers against doing harm to others.