Pliny the Elder [1st century CE] (Natural History, Book 8, 41): [Book 8, 40] The stork drugs itself with marjoram in sickness... [Book 10, 31] Where exactly storks come from or where they go to has not hitherto been ascertained. There is no doubt that they come from a distance, in the same manner as do cranes, the former being winter visitors and the latter arriving in summer. When about to depart they assemble at fixed places, and forming a company, so as to prevent any of their class being left behind (unless one captured and in slavery), they withdraw as if at a date fixed in advance by law. No one has seen a band of storks departing, although it is quite clear that they are going to depart, nor do we see them arrive, but only see that they have arrived; both arrival and departure take place in the night-time, and although they fly to and fro across the country, it is thought that they have never arrived anywhere except by night. ... Some persons declare that storks have no tongue. They are held in such high esteem for destroying snakes that in Thessaly to kill them was a capital crime, for which the legal penalty was the same as for homicide. [Book 10, 32] (Storks return to the same nest. They nourish their parents' old age in their turn. - [Rackham translation]

Aelianus [170-230 CE] (On the Characteristics of Animals, Book 1, 37): Storks have a very clever device for warding off the bats that would damage their eggs: one touch from the bats turns them to wind-eggs and makes them infertile. Accordingly, this is the remedy they use to prevent this happening. They lay the leaves of a plane-tree upon their nests, and directly the bats come near the storks, they are benumbed and become incapable of doing harm. - [Scholfield translation]

Gaius Julius Solinus [3rd century CE] (De mirabilibus mundi / Polyhistor, Chapter 40.25-27): [Chapter 40.25] There is a place in Asia in the open plains called Pythonos Come, where all the storks fly at the time of their first arrival. They tear the one who gets there last to pieces. These birds, they say, have no tongues, and the rattling sound they make is produced by their mouths rather than by their voices. [Chapter 40.26] Storks possess extraordinary pietas: the same length of time as they spend educating their young, they themselves are in turn nourished by their own chicks. They cherish their nests so immoderately, that they lose their feathers from the constant sitting. [Chapter 40.27] It is regarded an impious act in all places to harm storks, but in Thessaly most of all. Here there is an abundance of frightful serpents, which the storks pursue and eat, thus removing much evil from the Thessalian region. - [Arwen Apps translation, 2011]

Saint Ambrose [4th century CE] (Hexameron, Book 5, 16.53): It is related that storks proceed in orderly array in the direction in which they propose to advance and that in many places in the East they form ranks together as if they were soldiers marching under the command of an officer. You could well believe that you were witnessing an army going forward with banners displayed such is the pageant of military precision which they show. They are under the leadership and direction of crows who accompany them, providing a stout escort and auxiliary force against any attacking army of birds. They undertake at their own risk campaigns that are planned by others. A proof of this is deduced from the fact that these crows are not found to stay any length of .time in these regions. - [Savage translation, 1961]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 7:16-17): Storks (ciconiae) are named after the noise they make [canere, "sing"], which is not from their voice but from the rattling of their beaks. Storks are the heralds of spring, the enemies of snakes and the companions of society. They fly in line across seas to Asia, preceded by two crows who they follow like an army. They take extraordinary care of their young, even to the extent of loosing their feathers through constant brooding; but later their young feed them for as long as they spent raising their children.

Hugh of Fouilloy~> [ca. 1100-1172 CE] (De avibus, chapter 47): Storks (ciconiae), like crickets (cicaniae) are so called from their chattering sound, which [is considered] to be a sound of the beak rather than of the voice, because they make it by clacking the beak. These messengers of Spring, companions of society, enemies of snakes, fly across the sea, [and] proceed as a flock into Asia. Crows precede them as leaders, and [the storks] follow like an army. [Storks] have an exceptional sense of duty toward their offspring. For so much more [than other birds] do they warm their nests, that they constantly pluck out their feathers in brooding. Moreover, as much time as they spend in rearing a brood, so much are they in turn nourished by their offspring. For a call, storks make an oral sound by clattering the beak. Moreover, they represent those who give utterance to their wicked deeds with wailing and gnashing of teeth. They are the messengers of spring, because they show to others the moderation of the converted mind. They are the companions of society because they willingly live among the brethren. It is said of the stork that it is the enemy of snakes. The snakes are wayward thoughts or wayward brothers whom the stork pierces with its beak, while the righteous man checks improper thoughts or reproves the wayward brother with stinging invective. "They fly across the sea, [and] proceed as a flock into Asia." Asia means high. Therefore, he who reaches for the heights, having scorned the tumults of the world, crosses the sea and proceeds into Asia. [Storks] have "an exceptional sense of duty toward their off spring," with the result that they pluck out their feathers over them in constant brooding. Storks pluck out feathers over their chicks in constant brooding, because when priests nourish their charges, they remove from themselves the feathers of excess and weakness. Furthermore, as much time as they gave to rearing the offspring, that much are they nourished in return by their chicks. However long the young have need of them, so long must the storks nourish them, because for however long the pupils have need, so long must the priests nourish them by the word of instruction. Likewise, their charges should cherish the priests by their efforts, so that [the priests] might provide them with the necessities which they are lacking. Thus, the turtledove and the swallow and the stork reprove those who do not believe that Christ appeared incarnate, and who do not fear the coming judgement of the Lord. - [Clark translation, 1992]

Gerald of Wales [c. 1146 – c. 1223] (Topographia Hibernica, chapter 14): It is remarkable in storks that they desert places where the waters are warm, and frequent those where they are cold. For throughout the winter they harbor about the beds of streams, but in the first opening of spring change the temperature, betaking themselves to a free current of air. So the saints, who now sleep in the dust of the earth, during the wintry season of this world, which now is, when it is renovated and changed into a better state, enjoying for ever a serene atmosphere, will rise from their hiding-places at the first sound of the archangel's voice - [Forester translation, 1863, chapter 14]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.28): For they are named, as Solinus says, from the sound with which they rattle, which is of the beak rather than of the voice. Now the storks are rattling for a reason: to prepare for its arrival, and this in congratulation; because of birds flying overhead, and this in fear; because of anger, and this in defense; for the sake of victory, like a cock, and this in exaltation. A stork lays eggs or rears chicks according to the want or sufficiency of food: if there is plenty of food, many, if there is little food, a few, but not less than three, unless by chance one of the eggs that are laid perishes. A stork, seeing a heavy wind or hail threatening - for animals are more shrewd in discerning the events of the wind - with outstretched wings and mouth turned to the wind places itself over the chicks and for these usually endures dangers. As they cross the seas, they are led by crows which precede their army. The value of storks in killing snakes is so high in Thessaly that it was a capital crime to kill a stork, as though it was murder, as Pliny tells us. Storks have the greatest affection for their young, so much so that, while tending to the nests, they constantly stoop down and lose their feathers; but even the chicks have no less exceptional piety towards their mothers. For as much time as mothers spend in bringing up their young, so much time are they themselves nourished by the young. Hence it is called a pious bird. They reuse their nests every year. But wherever they do not want to return to their usual nests, the common people think the nest to be deserted. It seems that the stork has a very rheumatic head, because its beak almost continuously drips water, and this more so in winter. This kind of bird is in many ways a hunter of snakes, and although it eats them and other poisonous things, yet, as Andelmus says, it does not die. As Pliny says, the stork is a remedy against a poisoned stomach. They deliver one of their offspring to the lord of the place, under which they breed, to throw down a feather as a tribute; but perhaps there is a greater reason for the tedium of nursing. To what place they go, or where they come from, is still unknown. When they prepare to leave, as Solinus says, they assemble in a certain place, so that none of their kind is left but captives. In Asia there is a field where they gather together and mutter, and the one that comes last, tear it to pieces, and thus depart. - [Badke translation/paraphrase]

Albertus Magnus [ca. 1200-1280 CE] (De animalibus, Book 23, 36): Some misinformed individuals have upheld the untenable claim that storks migrate to parts of the Orient during the winter, and that there is an open plain in Asia where they await the arrival of their fellows. The same authors claim the storks bite and peck at stragglers in the flock which delay the progress of the migration, in the same way that crows round up and defend truant members of their flocks but in the process peck at the vagrants until they return to the flock wounded and covered with blood. This story of the storks is patently false for three reasons. First, the zones of latitude that extend from East to West have the same climatic conditions in terms of heat and cold; therefore there would be no advantage for the storks to migrate eastward in the winter, Second, it is well known that the storks leave the entire region in which we live and remain in no part of this habitable world. Third, the stork is a cold-blooded bird that consumes cold, viscous foodstuffs and consequently must hibernate during the season when phlegm is generated, as we explained before. In all truth, the location of the stork’s hibernation has never been ascertained, since at that time they hide away in marshy wastelands and coverts, secreting themselves like other hibernating animals. Another tale relates that the male stork can sense when his mate has engaged in an adulterous union by the smell emanating from her body, unless she has first taken the precaution of washing in the waters of a spring. But this mistaken report is nothing short of a fable. - [Scanlan]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book12.8): A Storke is a water fowle, and purgeth hir selfe with his owne bill: For when she séeleth hir selfe griened with much meate, she taketh Sea water in hir bill, and putteth it in at hir harder hole, and so into hir guttes, and that water suitneth the hardnesse of ye meat, and biting the guts causeth them to put superfluities. Also this bird easeth egs of Adders and Serpentes, and beareth them for best meate to hir birdes, as Isidore saith. And this bird is called Siconia, as it were Sicannia, for he smiteth or flappeth with his bill, and maketh a noyse as it were with a Cane or a great Réeds, as he saith. Also he is messenger of springing time, and in hir comming, betokeneth noveltie of time, and is enemie to Adders and Serpents, and beateth and slayeth them with hir bill, and sometime swalloweth and devoureth them, and haunteth and loveth company of men, and therefore they make theyr neasts on houses that men dwell in, & they leane not lightly their first neaste, except they be compelled. But ere they go into other countries against Winter, they fill their neasts with earth, & draw the twigges and thornes of their neasts with fenne, that no tempest of winde should breake it nor throw it downe in Winter, and in hir comming againe in springing time, she occupieth the same place, and defendeth the neast from other that would occupy it: while the female liveth the male accompanieth not with another with service of Venus, but kéepeth truely to hir in neast and in office of generation. And if the male espieth in any wise, yt the female hath broke spousehood, she shall no more dwell with him, but he beateth and striketh hir with his bill, and slaieth hir if he may, as Arist[otle] saith. The male treadeth not the female but in the neast: and in sitting on brood, the male and the female chaunge times, and love their birds, & kéepe them with right great affection, and for busie sitting uppon them, their fethers fall, and when the male travayleth about meate, the female sitteth in the neast, and againward. And when the male commeth home, the female flyeth out for meate, and then the male sitteth on the neast, as Ambrose saieth. Storkes flye over the Sea, in flockes, and flye together into hot countries, and in their passing, Crowes flye with them, & passe before them, as it wer leading the Storkes, and withstand with all their might, fowles yt hate Storkes, as it is sayd in Exameron. And though storkes eate venemous beasts, as frogs, Adders and serpents, and other such, yet neverthelesse the venime overcommeth not, neither chaungeth their kinde, but is to them féeding and nourishing, that is venimous to men and to other beasts: for by vertue of heate, that hath mastrie within them, the mallice of venime is quenched. Also when their birdes are haught, they have féete, legges, and bills full blacke, as Swans have, but ye blacknesse passeth away lyttle and lyttle. And the more olde they were, the more redde they have legs, féete & bills. - [Batman]

Slavic Physiologus [15th - 16th century]: The stork, called pelargos, loves his children very much. He is thin from the waist down and thick from the waist up. And he does not leave his nest [empty but sits there], sometimes the male and sometimes the female. - [Stoykova, English translation by Mladenova and Stoykov]