Aristotle's Explanations of Bird Migration

Abstract

The migrations of birds have attracted the attention and excited the imagination of man since antiquity. The earliest contributions to the study of this phenomenon date back 3,000 years ago, to the times of Hesiod, Homer, Herodotus, Anacreon and Aristophanes. However, the first systematic study of birds began in the 4th-century BCE with Aristotle.

A search for ornithological material in Aristotle’s zoological or biological writings (Περὶ τὰ ζῷα ἱστορίαι, Περὶ ζῴων μορίων, and Περὶ ζῴων γενέσεως) reveals his attempt to explore the whole field of bird life. The Macedonian philosopher and naturalist displayed specific interest in the morphology, anatomy, physiology, classification and behaviour of birds (ὄρνιθες/ὄρνεα/πτηνά), and provided explanations of their diet, habitat, migration and reproduction (mating, conception, hatching and generation of young).

In my paper I examine Aristotle’s explanations of the periodic movements of birds from one geographic location to another and evaluate it under the scope of contemporary avian biology. In regards to that, I develop my analysis in two parts.

In the first part I focus my attention on Historia Animalium (Περὶ τὰ ζῷα ἱστορίαι), Book VII (VIII), Chapter 12, and analyze Aristotle’s observations on the following issues: (a) the seasonal movements of cranes (γέρανοι), pelicans (πελεκᾶνες), cuckoos (κόκκυγες), quails (ὄρτυγες), turtle doves (τρυγόνες), swallows (χελιδόνες), swans (κύκνοι) and geese (χῆνες), (b) the comparison of avian migration to human behaviour, (c) the altitudinal avian migration or short distance migration, and (d) the pre-migratory avian metabolism.
In the second part I deal with Aristotle’s two ‘unusual’ explanations for small birds disappearing in winter (Historia Animalium, Book VII (VIII), Chapter 16): (a) the theory of hibernation [certain kinds of birds go into a torpid (inactive) state in cold weather], and (b) the theory of transmutation or bird-to-bird-transformation.

The present paper has two aims. The first and foremost aim is to provide a re-reading and re-examination of Aristotle’s knowledge of avian migration through it’s connection to current biology.

The second aim is to show that the Stageirite philosopher may have been the first person to study and discuss ‘scientifically’ bird migration ‘in anything like the spirit which moves a modern naturalist’.

Full text

MAY 23-28, 2016
Proceedings of the World Congress
Aristotle
2400 Years
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WORLD CONGRESS “ARISTOTLE 2400 YEARS”
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MAY 23-28, 2016
|
ARISTOTLE UNIVERSITY OF THESSALONIKI,
ANCIENT STAGEIRA,
ANCIENT MIEZA
SECTION I:
PHILOSOPHY OF NATURE PART 2:
BIOLOGY
Aristotle’s Explanations of Bird Migration
Christina S. Papachristou, GREECE
animal life. The remaining treatises aim at eliciting
theory from the recorded facts.”
3
Aristotle in Historia animalium [Book VII(VIII).
12, 596b 20 – 597b 30, and 16, 600a 11-28] writes
about bird migration, the mechanism behind the
seasonal appearance and disappearance of some
species of birds. Peter Berthold asserts that “with-
out doubt the history of bird migration studies
started with Aristotle, who ‘raised ornithology to
the rank of a science’, as Stresemann
4
(1951) con-
firmed in his Entwicklung der Ornithologie
5
(De-
velopment of Ornithology).”
6
Taking into account the previous view, the aim
of the present paper is to study Aristotle’s explana-
tions of the periodic movement of birds from one
geographic location to another and back again and
evaluate it under the scope of contemporary avian
biology.
3. David Ross, Aristotle. With an Introduction by John L.
Ackrill (London and New York: Routledge, 1995), 118.
4. Erwin Stresemann (1889-1972) was one of the most im-
portant ornithologists of the 20th century.
5. Erwin Stresemann, Die Entwicklung der Ornithologie
von Aristoteles bis zur Gegenwart (Berlin: F.W. Peters, 1951).
6. Peter Berthold, Bird Migration: A General Survey, 2nd edi-
tion (Oxford - New York: Oxford University Press, 2001), 11.
Introduction
The migrations
1
of birds have attracted the atten-
tion and excited the imagination of man since an-
tiquity. The earliest contributions to the study of
this phenomenon date back 3,000 years ago, to the
times of Hesiod, Homer, Herodotus, Anacreon,
and Aristophanes.
However, the first systematic study of birds be-
gan in the 4th-century BCE with Aristotle. A
search for ornithological material in his zoological
or biological writings reveals his attempt to ex-
plore the whole field of bird life. The Macedonian
philosopher and naturalist displayed specific in-
terest in the morphology, anatomy, physiology,
classification and behavior of birds (ρνιθε/
ρνεα/πτηνά), and provided explanations of their
diet, habitat, migration and reproduction (mating,
conception, hatching and generation of young).
The principal sources of information on the na-
ture and kinds of birds are the following works: (a)
Historia animalium (Περὶ τὰ Ζῷα Ἱστορίαι),
2
(b)
De partibus animalium (Περὶ Ζῴων Μορίων) and
(c) De generatione animalium (Περὶ Ζῴων Γενέσε-
ως). Whereas, the most valuable work on the sub-
ject of ornithology, is contained in Historia ani-
malium, which, according to Ross, “is a prelimi-
nary work that aims at recording the main facts of
1. Migration is not just for the birds. Many creatures, like
fish, mammals, reptiles, amphibians, and even insects migrate.
2. Cf. Aristotle, Historia animalium, II.12, 503b 29 – 504b
13, and 17, 508b 26 – 509a 24; IV.9, 536a 20-32 and 536b 14-
19, and 10, 536b 24-32; V.5, 541a 27-31, and 8, 542b 2-28, and
13, 544a 25 – 544b 11
;
VI.1, 558b 9-10, 564b 14; VII(VIII).3,
592a 29 – 594a 4, and 12, 596b 20 – 597b 30, and 16, 600a 11-
28, and 18, 601a 26 – 601b 5; VIII(IX).7, 612b 18-36, and
620b 10.
Image
1
.
[Barn] Swallow
(Hirundo rustica).
Drawn from Nature & on
stone by J. & E. Gould
(Plate 54) from Volume II
of John Gould’s
The Birds of Europe, 1837.

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–  –
north to cold places after the vernal equinox (α-
ριν σηερία) in search of alternate food sourc-
es.
It must be added here that in the springtime after
the winter solstice, according to Aristotle, the Orni-
thiae or Bird-winds (ρνιθίαι) blow from the north.
These annual winds were called Ornithiae because
migratory birds arrived with them in Greece.
οίω δ κα ετ χειεριν τροπ πνέουσιν
ο ρνιθίαι κα γρ οτοι τησίαι εσν σθενε
λάττου δ κα ψιαίτεροι τν τησίων πνέουσιν
(Aristotle, Meteorologica, II.5, 362a 22-24)
The philosopher notices that cranes (γέρανοι)
travel from the steppes of Scythia (near the Black
Sea, i.e., Russia) to the marshlands south of Egypt,
where the [Blue] Nile River originates, i.e., Central
Africa (near Lake Tana in Ethiopia):
εταβάλλουσι γρ κ τν Σκυθικν πεδίων ε τ
λη τ νω τ Αγύπτου θεν  Νελο ε στι δ
 τόπο οτο περ ν ο πυγαοι κατοικοσιν ο
γάρ στι τοτο θο λλ’ στι κατ τν λήθει-
αν γένο ικρν ν σπερ λέγεται, κα ατο κα
ο πποι, τρωγλοδύται δ’ εσ τν βίον. (Aristotle,
Historia animalium, VII(VIII).12, 597a 5-9)
Among the birds (ρνεα) the cranes migrate a long
way and fly to a great height:
τν ν ον ρνέων α γέρανοι, καθάπερ ερη-
ται πρότερον, κτοπίζουσιν ε τ σχατα κ τν
σχάτων. πέτονται δ πρ τ πνεα. (Ibid.,
VII(VIII).12, 597a 30 – 597b 1)
1. Migration of Birds:
Cranes, Pelicans, Cuckoos, Quails,
Doves, Swallows, Swans and Geese
The Stageirite philosopher may have been the first
person to study “scientifically” bird migration.
7
He
was “the first to discuss migration in anything like
the spirit which moves a modern naturalist.”
8
All animals, says Aristotle, have an innate per-
ception (ασθησι σύφυτο) of the changes of
temperature. Some of them find protection in
their accustomed locations (συνήθεσι τόποι),
while other migrate. Creatures that are able to
change their locations spend their winter in warm
lands, where food is more abundant, and their
summer in cold ones. The philosopher compares
bird migration to human behavior asserting, “that
wealthier people often change their place of resi-
dence seasonally to pursue comfort in more equi-
table climes, and so do cranes, pelicans, swans,
geese, doves and quails.”
9
πάντα γρ τ κατ τ θερν κα ψυχρν ετα-
βολ ασθησιν χει σύφυτον, κα καθάπερ τν
νθρώπων ο ν ν το ψυχρο χειάζουσι δ’
ν το λεεινο, οτω κα τν ζων τ δυνάε-
να εταβάλλειν το τόπου. κα τ ν ν ατο
το συνήθεσι τόποι ερίσκεται τ βοηθεία, τ
δ’ κτοπίζει, ετ ν τν φθινοπωρινν σηερίαν
κ το Πόντου κα τν ψυχρν τόπων φεύγοντα
τν πιόντα χεινα, ετ δ τν αρινν κ τν
θερν ε το τόπου το ψυχρο φοβούε-
να τ καύατα, τ ν κ τν γγ τόπων ποιού-
ενα τ εταβολά, τ δ κα κ τν σχάτων 
επεν. (Aristotle, Historia animalium, VII(VIII).12,
596b 24 – 597a 4)
Aristotle claims that there are many ρνιθε,
which migrate south to warm places after the au-
tumnal equinox (φθινοπωριν σηερία) and
7. Gaius Plinius Secundus (23-79 CE), also known as Pliny
the Elder, the Roman historian and naturalist displayed scien-
tific interest in the biology, behavior and movements of birds.
In his most famed work, the 37-volume Historia Animalium
(Natural History), repeats and discusses much of what Aristo-
tle wrote regarding bird migration.
8. J. H. Gurney, F. Z. S., Early Annals of Ornithology: With
Illustrations from Photographs and Old Prints (326 High Hol-
born, London: H. F. & G. Witherby, 1921), 11.
9. Janice M. Hughes, The Migration of Birds: Seasons on the
Wing (Buffalo, New York - Richmond Hill, Ontario: A Firefly
Book Ltd., 2009), 11.
Image 2. Source: Curt D. Meine and George W. Archibald (eds), The
Cranes: Status Survey and Conservation Action Plan (Gland, Switzerland:
International Union for Conservation of Nature and Natural Re-
sources, 1996), 161.

–  –
CHRISTINA S. PAPACHRISTOU ARISTOTLE’S EXPLANATIONS OF BIRD MIGRATION
(in Thrace, it flows south from Bulgaria) to the Ister.
Ister is the old Thracian and Greek name of the Dan-
ube River all the way from the mouth to the source:
κα ο πελεκνε δ’ κτοπίζουσι, κα πέτονται π
το Στρυόνο ποταο π τν Ἴστρον κκε τε-
κνοποιονται θρόοι δ’ πέρχονται, ναένοντε
ο πρότεροι το στερον δι τ ταν περπτνται
τ ρο δήλου γίνεσθαι το στέρου το προ-
τέροι. (Aristotle, Historia animalium, VII(VIII).12,
597a 9-14)
It is true that Strymon and Danube are two of the
most important wetlands in Europe. As the season
changes every year, the migrating birds, including
pelicans (Pelecanus phillipensis crispus and Pelecanus
onocrotalus), come and go, too (see Images 4 and 5).
Aristotle asserts that the cuckoo (κόκκυξ) ap-
pear for a short time in summer, and disappears in
winter. He considers, correctly enough, that the
cuckoo goes away/migrates about the time the
Dog Star (Seirios or Sirius)
14
rises, that is, in July.
It re-appears from springtime to the rising of the
Dog Star. The heliacal rising of Sirius marked the
flooding of the Nile in Ancient Egypt and the hot
days of summer for the ancient Greeks.
 δ κόκκυξ φαίνεται π’ λίγον χρόνον το θέ-
ρου, τν δ χεινα φανίζεται. (Aristotle, Histo-
ria animalium, VI.7, 563b 18-19)
Μεταβάλλει δ κα  κόκκυξ τ χρα κα τ
φων ο σαφηνίζει, ταν έλλ φανίζεσθαι φα-
νίζεται δ’ π κύνα, φανερ δ γίνεται π το
αρο ρξάενο έχρι κυν πιτολ. (Ibid.,
VIII(IX). 49Β 633a 11-14)
14. Seirios or Sirius (Σείριο) is the brightest star in the
night sky. It is also known as the “Dog Star” (Canicula Stel-
la).
How Aristotle concluded that cranes migrated?
(a) His own observations: as a naturalist he might
have watched cranes flying overhead. (b) The oral
tradition: he relied upon many oral reports of trav-
elers and bird fanciers who saw cranes on the
steppes of Scythia during the summer, and from
other travelers who saw cranes in the marshlands
of the Nile River during winter. (c) Written sources:
he obtained data from former writers (such as
Homer).
According now to contemporary ornithologists
Aristotle’s descriptions of cranes’ migration refer
without doubt to the regular seasonal movements
of the Common Crane (Grus grus),
10
also known as
the Eurasian Crane,
11
which is commonly found in
Europe (see Images 2 and 3). The Common Crane
“usually migrates on a narrow front, utilizing two
major migration routes (south-west, and south to
south-east passages across Europe) and uses regular
staging areas (Snow and Perrins 1998).”
12
Moreover, Aristotle says that pelicans (πελε-
κνε)
13
also, migrate and fly from the River Strymon
10. See Curt D. Meine and George W. Archibald, eds., The
Cranes: Status Survey and Conservation Action Plan (Gland,
Switzerland: International Union for Conservation of Nature
and Natural Resources, 1996), 164-165: Eurasian Crane in
“Greece M, X (b) [M = Present during migration (breeding
and wintering in other countries / X (b) = Extirpated: (b) as a
breeding species].”
11. See Janice M. Hughes, op. cit., 11.
12. Encyclopedia of Life, Grus grus <http://eol.org/pag-
es/1049273/details>.
13. See William Geoffrey Arnott, Birds in the Ancient World
from A to Z (London and New York: Routledge, 2007), 172:
“In Greece today, two species of Pelican [Πελεκάν] survive in
the few remaining wetlands of northern Greece: the Dalma-
tian or Grey (now Pelecanus phillipensis crispus) and the
White Pelican (Pelecanus onocrotalus), but up to the nine-
teenth century the Dalmatian bred as far south as Attica.”
Image 3. Common Crane (Grus grus).
Drawn by John Gould, Joseph Wolf,
H.C.Richter & Wm. Hart; Lithographed
by H.C. Hart & Wm. Richter, 1837.
Image 4. Dalmatian Pelican (Pelecanus crispus, Feld.).
Edward Lear’s illustration (Plate 406) from Vol. V of
John Gould’s The Birds of Europe, 1837.
Image 5. White Pelican (Pelecanus onocrotalus,
Linn.). Edward Lear’s illustration (Plate 405)
from Vol. V of John Gould’s op. cit.

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–  –
νω δι τ καύατα. ποιεται δ’ ε τ σθενέστε-
ρα πρτα τν ετάστασιν καθ’ κατέραν τν περ-
βολήν, οον ο ν σκόβροι τν θύννων ο δ’ ρτυ-
γε τν γεράνων τ ν γρ εταβάλλει το Βοη-
δροινο τ δ το Μαιακτηρινο. (Aristotle,
Historia Animalium, VII(VIII).12, 597a 18-24)
Furthermore, of birds those who migrate and
never winter at the same place are the following
species: (a) ring doves or cushats (φάτται), which
are the common wood pigeons (Columba palum-
bus), (b) stock doves (πελειάδε) or wild pigeons
(Columba oenas), (c) swallows (χελιδόνε) or
[barn] swallows (Hirundo rustica),
19
(d) turtle
doves (τρυγόνε) or European turtle doves (Strep-
topelia turtur), (e) swans (κύκνοι), which are the
mute (Cygnus olor or mansuetus) and the whoop-
er (Cygnus cygnus) swans,
20
and (f) the small
goose ( ικρ χήν) or white-fronted goose
(Anser albifrons).
21
19. See Thomas East, Lones, “On the Identification of Some
of the Birds Mentioned by Aristotle,” The Zoologist, A Monthly
Journal of Natural History, No. 745 (July 1903): 245: “Whether
the House-Martin and the Crag-Martin, if that bird were
known separately by Aristotle, should also be included under
chelidon, is difficult to decide,” due to insufficient data.
20. See William Geoffrey Arnott, op. cit., 182: “Kyknos was
the Greek word in regular use for Swan, of which two species
then as now were found in the Balkan peninsula and Turkey:
the Mute Swan (Cygnus olor), breeding today as a totally wild
bird in eastern Thrace and parts of Turkey, but reaching as far
south as Attica up to the beginning of the twentieth century,
with a locally common influx of winter visitors; and the
Whooper (C.cygnus), now an uncommon passage migrant
and winter visitor to the Evros delta and Turkish wetlands. In
ancient times the two species were probably much commoner
and more widespread, but not yet sufficiently distinguished
from each other to warrant separate names.”
21. See Thomas East Lones, Aristotle’s Researches in Natural
Science: With Illustrative Drawings (London: West, Newman
& Co., Hatton Garden, 1912), 253.
Cuckoo is a widespread summer migrant to Europe
and Asia and winters in the warmer climates of sub-
Saharan Africa. It leaves Africa to breed in the cool-
er climates of Europe during the spring. The com-
mon cuckoo (European cuckoo or Cuculus canorus)
is a common parasite, which means it relies on oth-
ers to raise its young.
15
Once the cuckoo leaves its
offspring to the care of other birds, by the end of
July immediately migrates southward.
The Stageirite describes also cases of altitudinal
avian migration or a short distance migration, in
which birds move from lower elevations to higher
elevations and back, in response to weather condi-
tions and food supply. Weakly birds (τ σθεν
τν ρνέων), he says, migrate downslope in win-
ter for warmth, and in the summer they retreat to
higher in the mountains for coolness. Weakly birds
are the first to migrate on account of extremes of
temperature, either hot or cold. For example, the
[common] quails (ρτυγε)
16
come down to
warmer elevations near the sea level in the month
of Boedromion (Βοηδροιών),
17
while the cranes
start their southward journey in the month of
Maimakterion (Μαιακτηριών).
18
κα τ σθεν δ τν ρνέων ν ν τ χεινι κα
το πάγοι ε τ πεδία καταβαίνουσιν ε τ ρη
15. The cuckoos, says Aristotle, do not build nests but lay
in other birds’ nests. See Historia Animalium, VI.7, 563b 29
– 564a 3; VIII(IX).29, 618a 8-31.
16. Ὄρτυξ is the [Common] Quail, Coturnix coturnix or
Coturnix communis. It is a small, round game bird and be-
longs to the family of Phasianidae (including chicken, quail,
partridges, pheasants, turkeys, peafowl and grouse). It is the
only migratory Galliforme (an order of heavy-bodied ground-
feeding birds), but many are all year-round residents of
Greece.
17. Boedromion = a part of August and September.
18. Maimakterion = a part of October – November.
Image 6.
Common Cuckou
(Cuculus canorus, Linn.). J.
Gould’s illustration
(Plate 240) from Vol. III of
John Gould’s op. cit.
Image 7.
Common Quail
(Coturnis coturnis).
Drawn by John
Gerrard Keule-
mans, 1873.

–  –
CHRISTINA S. PAPACHRISTOU ARISTOTLE’S EXPLANATIONS OF BIRD MIGRATION
inconsistent? D. M. Balme believes that “these re-
ports suggest independent sources; factually, they
can all be reconciled with partial migration.”
22
Partial migration is a phenomenon in which
some individuals of a population migrate from the
breeding range while others remain resident. It is
found in a variety of animal groups, including
birds, fish, amphibians, insects and mammals.
Three main hypotheses have been proposed to ex-
plain partial migration: (a) the “Behavioral Domi-
nance hypothesis” suggests that subordinate indi-
viduals in a population migrate farther from the
breeding grounds because of competition with
dominant individuals (Ketterson and Nolan 1976,
Gauthreaux 1978, Myers 1981),
23
(b) the “Arrival
Time hypothesis” states that if individuals (adult
males) experience more intense competition for
breeding resources than the other, then these indi-
viduals should benefit by a more rapid return to
the breeding grounds (Ketterson & Nolan 1976)
24
and (c) the “Body-Size hypothesis” states that larg-
er and healthier individuals are less likely to mi-
grate or, if they migrate, to migrate shorter dis-
tances because of their ability to withstand colder
22. Aristotle, Historia animalium. Books 7-10, Loeb Classi-
cal Library, 1991, 135.
23. See E. D. Ketterson and V. Nolan, Jr, “Geographic Varia-
tion and its Climatic Correlates in the Sex Ratio of Eastern-
Wintering dark-eyed Juncos (Junco hyemalis hyemalis),” Ecol-
ogy 57 (1976): 679-693; S. A. Gauthreaux, Jr. “The Ecological
Significance of Behavioral Dominance,” in Perspectives in
Ethology, volume 3, eds. P. P. G. Bateson and P. H. Klopfer
(New York: Plenum Press, 1978), 17-54; J. P. Myers, “A Test of
Three Hypotheses for Latitudinal Segregation of the Sexes in
Wintering Birds,” Canadian Journal of Zoology 59 (1981):
1527-1534.
24. See E. D. Ketterson and V. Nolan, Jr, op. cit.: 679-693.
παίρουσι δ κα α φάτται κα α πελειάδε κα
ο χειάζουσι, κα α χελιδόνε κα α τρυγόνε.
(Aristotle, Historia animalium, VII(VIII).12, 597b
3-4)
γελαοι δ τν ρνίθων εσ γέρανο κύκνο πε-
λεκν χν  ικρό. (Ibid., VII(VIII).12, 597b 29-
30)
However, the philosopher at 593a 16-18 says that
the common wood pigeon (Columba palumbus)
appear at all seasons, whereas the turtle dove
(Streptopelia turtur) only in summer, for in winter
it goes into hiding/hibernates and is never seen.
φψ ν ον κα περιστερ ε φαίνονται, τρυγὼν
δ το θέρου το γρ χεινο φανίζεται φω-
λεύει γάρ.
(Ibid., VII(VIII).3, 593a 16-18
)
But at 600a 24-26 he says that some common
wood pigeons hide/hibernate, while others mi-
grate at the same time as the swallows.
τν δ φασσν νιαι ν φωλοσιν, νιαι δ’ ο φω-
λοσιν πέρχονται δ’ α τα χελιδόσιν. (Ibid.,
VII(VIII).16, 600a 24-26)
Finally, at 633a 5-9 Aristotle notices that the wood
pigeon utters no sound in the winter except when
there is fine weather.
πε κα  φάττα το ν χεινο ο φθέγγεται
(πλν ἤδη ποτ εδία κ χεινο σφοδρο γενο-
ένη φθέγξατο κα θαυαστώθη π τν πεί-
ρων), λλ’ ταν αρ γένηται, τότε ρχεται φωνεν.
(Ibid., VIIΙ(ΙΧ).36, 633a 5-9)
Why do the previous reports on the appearance or
migration of the wood pigeons and the turtle doves
through the winter show such differences / are so
Image 8.
Wood pigeon
(Columba palum-
bus, Linn.).
E. Lear’s illustra-
tion (Plate 243)
from Vol. IV
of John Gould’s
op. cit.
Image
1
0.
Stock Dove
(Columba oenas,
Linn.). Drawn by
J. & E. Gould
(Plate 244)
from Vol. IV
of John Gould’s
op. cit.
Image 9. Turtle Dove (Columba tur-
tur, Linn.). Drawn by J. & E. Gould
(Plate 246) from Vol. IV of John
Gould’s op. cit.

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–  –
temperatures and food shortages (Ketterson &
Nolan 1976).
25
Aristotle was probably the first to write that
birds are fatter before they migrate south in au-
tumn than when they return from migration the
following spring.
26
στι δ πιότερα πάντα ταν κ τν ψυχρν τό-
πων εταβάλλ  ταν κ τν θερν, οον κα
ο ρτυγε το φθινοπώρου λλον  το αρο.
(Aristotle, Historia animalium, VII(VIII).12, 597a
24-27)
It took more than 2,300 years before scientists
elaborated much on Aristotle’s observation about
avian flight metabolism. Today it is given that birds
must feast before long-distance flights on high-
energy foods to build fat stores for the journey
ahead. During migration some birds lose as much
25. See ibid.
26. See Janice M. Hughes, op. cit., 11.
as one fourth to one half of their entire body
weight, so it is necessary to store up enough fat for
energy (see Figure 1).
Migratory birds store up fat in thick layers “es-
pecially under the skin, and in well-defined de-
posits within the wishbone (tracheal pit) and
around the gut.”
27
Fat is indispensable as a fuel for
migratory flight. “At least 15 distinct fat depots
have been described in passerines (King & Farner
1965). Just before departure, the subcutaneous fat
layer in some long-distance passerine migrants
can be so extensive that most of the body appears
to be clad in a thick layer of pale-yellow fat, only
the central part of the breast muscle remaining
uncovered. This subcutaneous fat is relatively soft,
even at body temperature.”
28
2. Transmutation
and Hibernation of Birds
As we have already discussed, the accuracy of
many of Aristotle’s observations and conclusions
on the periodic movement of birds from one geo-
graphic location to another, has been confirmed in
contemporary times. Despite this fact, he is cred-
ited with two “unusual” explanations for small
birds disappearing in winter: birds either hiber-
nated, or turned into other species.
Aristotle was the originator of the theory of
transmutation — a theory that survived in various
forms until Charles Darwin’s time: the belief that
birds change species with the season. He noticed
that when the summer redstarts (φοινίκουροι)
29
27. Ian Newton, The Migration Ecology of Birds (London,
U.K.: Elsevier Ltd., 2008), 97.
28. Ibid., 97.
29. The [Common] Redstart (Phoenicurus phoenicurus) is a
Image
11
. Mute Swan (Cygnus olor or mansuetus,
Gmel.). E. Lear’s illustration (Plate 354) from Vol.
V of John Gould’s op. cit.
Image
12
. Whistling Swan, or Whooper (Cyg-
nus cygnus, Linn., Cygnus ferus, Ray). E. Lear’s
illustration (Plate 355) from Vol. V of John
Gould’s op. cit.
Image
13
. White-fronted Goose (Anser albi-
frons, Steph.). Drawn by J. & E. Gould (Plate
349) from Vol. V of John Gould’s op. cit.
Figure
1
. Flight distance (km) and flying time (hours) in still weather
for migratory birds which begin their journey with different amounts
of fat reserves and which fly until the fat runs out. Source: Thomas
Alerstam, David A. Christie (Translator), Bird Migration (Verlag:
Cambridge University Press, 1993), 285.

–  –
CHRISTINA S. PAPACHRISTOU ARISTOTLE’S EXPLANATIONS OF BIRD MIGRATION
Aristotle claimed to have seen these birds “in mid-
‘transformation’ — when their plumage coloration
displayed the attributes of both species.”
33
τι δ’  ατό στιν ρνι, ἤδη ὦπται περ τν ε-
ταβολν κάτερον τ γένο τοτο, οπω δ τε-
λέω εταβεβληκότα οδ’ ν θατέρ εδει ντα.
(Ibid., VIII(IX).49B 633a 2-4)
The philosopher probably saw these birds in the
middle of prebasic molt, in other words when many
avian species in the late summer and early fall
change their bright breeding plumage for more dull
winter colours. Anyone who has tried to identify
birds when they are experiencing the “fall molt”
(the periodic replacement of feathers by shedding
old feathers while producing new ones / feathers fall
out or break off and numerous patterns evolve) can
understand then Aristotle’s misidentification.
Aristotle’s “transmuting” birds could also have
been misidentified because of similarities in their
behaviours.
34
For example, the Redstart (Phoeni-
curus phoenicurus) “has many behaviours that re-
semble those of the European robin (Erithacus
rubecula). It has the same body carriage, the same
chat-like behaviour, and is the same size as the
robin, although its body is slimmer.”
35
33. Janice M. Hughes, The Migration of Birds: Seasons on the
Wing (Buffalo, New York - Richmond Hill, Ontario: A Firefly
Book Ltd., 2009), 12.
34. See ibid., 12.
35. GrrlScientist, “Mystery Bird: Common Redstart, Phoeni-
curus phoenicurus,” Science/The Guardian (Tuesday 30 August,
2011): <https://www.theguardian.com/science/punctuated-
equilibrium/2011/aug/30/4>.
disappeared as fall turned to winter, the red-
breasted robins (ρίθακοι)
30
showed up. It was ob-
vious to him that redstarts (Phoenicurus phoenicu-
rus) became/transformed or transmuted them-
selves into robins (Erithacus rubecula) in winter.
Likewise, garden warblers (συκαλίδε)
31
changed
into black-cap warblers (ελαγκόρυφοι)
32
at the
end of autumn.
Μεταβάλλουσι δ κα ο ρίθακοι κα ο καλούε-
νοι φοινίκουροι ξ λλήλων στι δ’  ν ρίθακο
χειερινόν, ο δ φοινίκουροι θερινοί, διαφέρουσι
δ’ λλήλων οθν  επεν λλ’  τ χρό όνον.
Ὡσαύτω δ κα α συκαλίδε κα ο ελαγκόρυφοι
κα γρ οτοι εταβάλλουσιν ε λλήλου. Γίνε-
ται δ’  ν συγκαλ περ τν πώραν,  δ ε-
λαγκόρυφο εθέω ετ τ φθινόπωρον. ιαφέ-
ρουσι δ κα οτοι λλήλων πλν τ χρό κα τ
φων. (Aristotle, Historia animalium, VIII(IX).49B
632b 27 – 633a 2)
small passerine bird. It is also known as the Eurasian or Euro-
pean redstart, the white-fronted redstart or simply as the red-
start. It is identifiable by its bright orange-red tail. It migrates
north to breed in Europe and western Asia and returns to
winter in sub-Saharan Africa.
30. The European Robin (Erithacus rubecula) is a small in-
sectivorous passerine bird. It is also known as robin redbreast
because of the distinctive orange breast of both sexes. It lives
in Europe and the United Kingdom. Birds living in the north-
ern parts of the habitat migrate southwards in winter.
31. The Garden Warbler - Beccafico (Sylvia borin) is a small
bird that breeds in most of Europe and in western Asia.
32. The Eurasian black-cap (Sylvia atricapilla) is a common
warbler. The black-cap is named for the male’s distinctive
black cap. It breeds in Europe, western Asia and northwestern
Africa.
Image
14
. Redstart (Phoenicurus
phoenicurus, formerly Phoenicurus
ruticilla, Swains). Drawn by J. & E.
Gould (Plate 95) from Vol. II of
John Gould’s op. cit.
Image
15.
Robin (Erithacus rubecula,
Swains). Drawn by J. & E. Gould
(Plate 98) from Vol. II of John Gould’s
op. cit.
Image
16.
Garden Warbler
(Sylvia borin Boddaert). Draw-
ing by Wilhelm von Wright
(1810-1887).
Image
17.
Black-Cap Warbler (Sylvia
atricapilla). Drawn by J. & E. Gould
(Plate 120) from Vol. II of John Gould’s
op. cit.

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–  –
Image
18.
Common House Mar-
tin (Delichon urbicum or Hirundo
urbicum, Linn.). Drawn by J. & E.
Gould (Plate 57) from Vol. II of
John Gould’s op. cit.
Image
19.
Red-rumped Swallow
(Cecropis daurica or Hirundo rufu-
la, Temm.). Drawn by J. & E.
Gould (Plate 55) from Vol. II of
John Gould’s op. cit.
Image
20.
Eurasian Crag Martin
or Rock Martin (Ptyonoprogne
rupestris or Hirundo rupestris,
Linn.). Drawn by J. & E. Gould
(Plate 56) from Vol. II of John
Gould’s op. cit.
Image
21.
Sand Martin (Riparia ri-
paria or Hirundo riparia, Linn.).
Drawn by J. & E. Gould (Plate 58)
from Vol. II of John Gould’s op.
cit.
Image
26.
Blackbird (Turdus meru-
la, Linn. Merula vulgaris, Ray).
Drawn by J. & E. Gould (Plate 72)
from Vol. II of John Gould’s op.
cit.
Image
27.
Crested Lark (Alauda/
Galerida cristata, Linn.). Drawn by
J. & E. Gould (Plate 165) from Vol.
III of John Gould’s op. cit.
Image
28.
Common or Eurasian
Sky Lark (Alauda arvensis, Linn.).
Drawn by J. & E. Gould (Plate
166) from Vol. III of John Gould’s
op. cit.
Image
29.
Mistle Thrush (Turdus
viscivorus, Linn.). Drawn by J. & E.
Gould (Plate 77) from Vol. II of
John Gould’s op. cit.
Image
22.
Red Kite (Milvus milvus,
Milvus vulgaris, Flem.). E. Lear’s
illustration (Plate 28) from Vol. II
of John Gould’s op. cit.
Image
23.
Black Kite (Milvus mi-
grans or Milvus ater). E. Lear’s
illustration (Plate 29) from
Volume II of John Gould’s op. cit.
Image
24.
White Stork (Ciconia
alba, Bellon). E. Lear’s illustration
(Plate 283) from Volume IV of
John Gould’s op. cit.
Image
25.
Black Stork (Ciconia
nigra, Bellon). E. Lear’s illustration
(Plate 284) from Volume IV of
John Gould’s op. cit.

–  –
CHRISTINA S. PAPACHRISTOU ARISTOTLE’S EXPLANATIONS OF BIRD MIGRATION
urbicum), (iii) Red-rumped Swallow (Cecropis
daurica), (iv) Eurasian Crag Martin (Ptyonoprogne
rupestris), (v) Sand Martin (Riparia riparia). All of
these birds are migratory and spend their winter
in Africa south of the Sahara, in Arabia and in the
Indian sub-continent. Aristotle had never been to
those places to see them there, and he had no re-
ports of them from travelers being anywhere else
in the known world.
37
So he determined that swal-
lows must hibernate during the cold season, hid-
den in holes, crevices, or hollow trees.
The Stageirite assigned hibernation not only to
swallows but also to kites (κτνοι),
38
storks (πε-
λαργοί),
39
[common] blackbirds (κόττυφοι),
40
37. See Armand Marie Leroi, The Lagoon: How Aristotle In-
vented Science (New York: Viking Penguin, 2014), 42: “The
world that Aristotle knew was bound by the Straits of Gibral-
tar to the west, the Oxus to the east, the Libyan desert to the
south and the Eurasian plains to the north.”
38. Ἰκτνο includes the Red Kite (Milvus milvus, formerly Mil-
vus regalis or Milvus ictinus) and the Black Kite (Milvus migrans
or Milvus ater). In ancient times the κτνο was well known to
people. “Today in Greece, the Red Kite is a rare winter visitor and
passage migrant, no longer breeding in Greece, while the Black
Kite is a rare resident (10-30 pairs) and a scarce winter visitor and
a passage migrant” (William Geoffrey Arnott, op. cit., 114).
39. Two species, white (Ciconia ciconia or Ciconia alba) and
scarcely black (Ciconia nigra) stork, are still summer visitors
to the northern part of Greece, although they can be seen
throughout the country.
40. Κόττυφο or κόσσυφο is the [Common] Blackbird
(Turdus merula ). It is a widespread and common resident in
the woodlands of Greece.
Along with transmutation and migration, was a
belief in hibernation. Aristotle set forth the theory
of hibernation, a theory that survived for more
than 20 centuries. He believed that the disappear-
ance of many species of birds as fall turned into
winter was explained by their passing into a torpid
(inactive) state where they remained during the
cold season, hidden (φωλοσι) in holes in trees or
in the ground. He observed that many swallows
(χελιδόνε) have been found in holes for the win-
ter, bare of all their feathers “and believed them to
be the smaller-bodied swallows awakening from a
featherless state of torpor (hibernation).”
36
φωλοσι δ πολλο κα τν ρνίθων, κα οχ ὣ τι-
νε οονται λίγοι  ε λεεινο τόπου πέρχο-
νται πάντε λλ’ ο ν πλησίον ντε τοιούτων
τόπων ν ο ε διαένουσι, κα κτνοι κα χελιδό-
νε, ποχωροσιν νταθα, ο δ πορρωτέρω ντε
τν τοιούτων οκ κτοπίζουσιν λλ κρύπτουσιν
αυτού. ἤδη γρ ὠέναι πολλα χελιδόνε εσν
ν γγείοι ψιλωέναι πάπαν. (Aristotle, Historia
animalium, VII(VIII).16, 600a 10-16)
In Greece there are five species of swallows (fam-
ily Hirundinidae): (i) [Barn] Swallow (Hirundo
rustica), (ii) [Common] House Martin (Delichon
36. Janet Schmidt, “Theory of Transmutation vs. Migration
Mythbusting,” Peninsula Clarion (15 July 2011): <http://
peninsulaclarion.com/outdoors/2011-07-15/refuge-notebook-
migration-mythbusting>.
Image
30.
Song Thrush (Turdus
musicus, Linn. or Turdus philome-
los, Brehm) & Redwing (Turdus ili-
acus, Linn.). Drawn by J. & E.
Gould (Plate 78) from Vol. II of
John Gould’s op. cit.
Image
31.
Field-fare (Turdus pilaris,
Linn.). Drawn by J. & E. Gould
(Plate 76) from Vol. II of John
Gould’s op. cit.
Image
32.
Starling (Sturnus vul-
garis, Linn.). Drawn by J. & E.
Gould (Plate 210) from Vol. III of
John Gould’s op. cit.
Image
33.
Starling (Sturnus vul-
garis, Linn.). Drawn by J. & E.
Gould (Plate 210) from Vol. III of
John Gould’s op. cit.

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–  –
turtle doves (τρυγόνε),
41
larks (κόρυδοι),
42
ring
doves (φάτται),
43
song thrushes (κίχλαι),
44
[com-
mon] starlings (ψάροι),
45
and little owls (γλα-
και).
46
κα κτνοι κ τοιούτων κπετόενοι χωρίων, ταν
φαίνωνται τ πρτον. φωλοσι δ’ οθν διακε-
κριένω κα τν γαψωνύχων κα τν εθυω-
νύχων φωλε γρ κα πελαργ κα κόττυφο
κα τρυγὼν κα κόρυδο, κα  γε τρυγὼν ολο-
γουένω άλιστα πάντων οθε γρ  επεν
λέγεται τρυγόνα δεν οθαο χεινο. ρχε-
ται δ τ φωλεία σφόδρα πίειρα οσα, κα πτε-
ρορρύει ν ν τ φωλεί, παχεα έντοι διατε-
λε οσα τν δ φασσν νιαι ν φωλοσιν, νι-
αι δ’ ο φωλοσιν πέρχονται δ’ α τα χελι-
δόσιν. φωλε δ κα  κίχλη κα  ψάρο κα τν
γαψωνύχων κτνο λίγα έρα κα  γλαύξ
(Aristotle, Historia animalium, VII(VIII).16, 600a
17-27)
41. European turtle doves (Streptopelia turtur).
42. Aristotle describes (Historia animalium, VIII(IX).25,
617b 20-24) two species of the κόρυδο (also κορυδό,
κορύδαλο, κορυδαλό, κορυδαλλό, κορυδαλλί): i) the
Crested Lark (Alauda/Galerida Cristata, Linn.), “a permanent
resident in Greece,” and ii) the Common or Eurasian Skylark
(Alauda arvensis, Linn.), “a winter migrant” [see D’ Arcy
Wentworth Thomson, A Glossary of Greek Birds (Oxford: at
the Clarendon Press, 1895), 96]. In Greece today are found
five species (Arnott, op. cit., 172): 1) Greater Short-toed Lark
(Calandrella brachydactyla), 2) Crested Lark (Alauda/Galeri-
da cristata), 3) Wood Lark (Lullula arborea), 4) Common or
Eurasian Skylark (Alauda arvensis), 5) Calandra Lark (Mel-
anocorypha calandra).
43. Ring doves or cushats (φάτται) are the common wood
pigeons (Columba palumbus).
44. Aristotle describes three species of the κίχλη (Histo-
ria Animalium, VIII(IX).20, 617a 18-23), that is applied to
the genus Turdus: 1) the ξοβόρο, which is the Mistle
Thrush (Turdus viscivorus), 2) the τριχά, which is probably
the Song Thrush (Turdus philomelos), and 3) the λιά,
which is probably the Redwing (Turdus ili acu s). “It surpris-
es modern ornithologists that Aristotle here makes no sep-
arate mention of the Field-fare (Turdu s pilaris) also a com-
mon winter visitor to Greece. Possibly it was not distin-
guished from the Mistle Thrush, being similar in size (25.5
cm) and also heavily spotted on the breast” (see Arnott, op.
cit., 140-141).
45. Ψάρ, ψρ οr ψάρο, ψρο is the [Common] Starling
(Sturnus vulgaris). In modern Greek it is the ψαρόνι,
αυροπούλι. Starlings are gregarious and migrate short dis-
tances in winter.
46. Γλαύξ is the Little Owl (Athene noctua). In modern
Greek is the κουκουβάγια.
His theory survived for more than two thousand
years. Olaus Magnus, Bishop of Uppsala, Sweden,
in his 1555 work entitled Historia de Gentibus
Septentrionalibus (History of the Northern People)
wrote that when fishermen in northern waters
pulled their nets from the lakes or ponds they
sometimes had a mixed catch of fish and hiber-
nating swallows (see Image 34). Swallows, swifts
and martins, according to Magnus, congregate in
marshes during autumn, allow themselves to
gradually sink into the mud, settle down and hi-
bernate soon.
47
Image
34.
Hibernating swallows drawn with fish from water. Source:
Olaus Magnus, Historia de Gentibus Septentrionalibus (Rome: Giovanni
Maria de Viottis, 1555).
It was not until the end of the 18th century that
migration and not hibernation was accepted as
an explanation for the disappearance of swallows
and other kinds of birds in the fall. Whereas, it is
interesting to note, although the particular birds
Aristotle observed are not hibernators, “in 1946
an American naturalist specializing in desert
wildlife, Dr. Edmund Jaeger, discovered a com-
mon poorwill, a species of small nightjar, in a
state of extended torpor,
48
which amounted to
hibernation,
49
in a rock crevice in the Chuckwal-
47. Carolus Linnaeus (1707-1778), George-Louis Leclerc,
Comte de Buffon (1707-1788) and George Cuvier (1769-
1832) believed in the hibernation of swallows. In 1878, Elliott
Coues, one of the founders of the American Ornithologist
Union, listed as many as 182 papers dealing with the hiberna-
tion of swallows.
48. Torpor is a short-term reduction of body temperature
and metabolic rate during times of cold exposure, food
shortage, or drought. Torpor usually lasts for less than 12
hours.
49. Hibernation is an extended form of torpor.

–  –
CHRISTINA S. PAPACHRISTOU ARISTOTLE’S EXPLANATIONS OF BIRD MIGRATION
Conclusion
The aim of this paper was to outline the Aristote-
lian explanations of bird migration. From the
analysis undertaken before we could say that the
Stageirite philosopher was the first natural physi-
ologist to write about the seasonal movements of
birds as an observable fact. His research on birds
appears to be rooted in the ancient Greeks’ cul-
tural interest in those living beings and in his own
attention to them. It led him to conduct observa-
tions, the accuracy of which remains astonishing
in many cases (see altitudinal avian migration,
partial migration, avian flight metabolism).
53
Finally, it is not necessary to say, if Aristotle had
been able to use the tools and techniques of con-
temporary ornithology to study bird migration, as
for example radar, VHF radio-tracking transmit-
ters, bird ringing and field reports from people
around the world, he would never have suggested
that redstarts transmuted themselves into robins,
and swallows hibernate in winter.
53. William Mcgillivray, Lives of Eminent Zoologists: From
Aristotle to Linnaeus: With Introductory Remarks on the Study
of Natural History, and Occasional Observations on the Prog-
ress of Zoology (Edinburgh: Oliver & Boyd, Tweeddale Court
- Simpkin & Marshall, London, 1834), 73: “the observations
of Aristotle, considering the period at which he lived, and the
proneness of the human intellect to wander from the true
path, are remarkable for the great proportion of truth which
they present to us. Whatever may be their actual merits, they
are certainly superior to those of any other naturalist whose
works have come down to us from the remote ages of classical
antiquity.”
la Mountains of southern California. Further re-
search showed that the species did effectively hi-
bernate and that the name given to it by Native
Americans of the Hopi tribe meant ‘the sleeping
one’ [Hölchoko].”
50
The non-migrating common poorwill (Pha-
laenoptilus nuttallii, Audubon, 1844)
51
or “the
sleeping one” to the Hopi, is the first avian species
known to hibernate for weeks or even months un-
der natural conditions. Researchers found that “in
hibernating poorwills, Tb falls to as low as 4.8 °C
and BMR [Basal Metabolic Rate] drops from 0.80
to 0.06 ml O2/g/h (a decrease of 93%).”
52
Scientists have also found that certain birds,
such as hummingbirds, swifts, nightjars or goat-
suckers, and nighthawks go into an extremely
torpid condition for brief periods (“temporary
hibernation”) in cold weather. Whereas, they
don’t sink into the mud and sleep, as Magnus as-
serted. Thus Aristotle was wrong about the swal-
lows. But he was not wrong about hibernation.
50. Michael McCarthy, Say Goodbye to the Cuckoo: Migra-
tory Birds and the Impending Ecological Catastrophe (Great
Britain: John Murray, 2009), 26.
51. It is the smallest member of the North American night-
jar family.
52. M. E. Fowler and R. E. Miller, Zoo and Wild Animal
Medicine (Philadelphia: W. B. Saunders Co, 2003), 225.
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PROCEEDINGS OF THE WORLD CONGRESS “ARISTOTLE 2400 YEARS”
|
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