UC-NRLF
B 3 an 7DD
THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
PRESENTED BY
PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID
THE MIGRATION OF BIRDS
A CONSIDERATION OF HERR GATKE'S VIEWS
BY
F. B. 1WHITLOCK
Author of " Birds of Derbyshire," <&c., <&c.
(ALL EIGHTS RESERVED)
3Lonfcon
E. H. POETEE
7, PRINCES STREET, CAVENDISH SQUARE, W.
1897
YV
PREFACE.
MIGBATION has, to me, always proved the most fascinating
feature of bird life. I therefore looked forward to the appear-
ance of Herr Gatke's long-expected work with the greatest
interest. On its first perusal, the novelty of the author's state-
ments greatly impressed me, and after careful study I found them
very difficult of acceptance. I then formed the plan of writing
a paper to one of the current ornithological journals, calling
attention to what I considered were the principal objections.
I soon found, however, that the subject was too great for this
to be practicable. After some hesitation I decided to publish this
little work on my own responsibility.
To prevent misconception, I must here state that the first
draft of my manuscript was completed before I saw Mr. W.
Eagle Clarke's "Digest of the Reports on Migration;" and
though I was glad of the opportunity the latter gave me of
strengthening my arguments, it must be understood that where
our conclusions are identical, they have been arrived at quite
independently of one another.
In writing my commentary I hope I have succeeded in guard-
ing against any expression at all likely to convey the idea that I
hold any feelings towards Herr Gatke but those of the warmest
admiration and respect.
My sole aim has been to place the other side of the question
before my readers, to the best of my ability.
F. B. W.
49, Gregory Boulevard, Nottingham.
January, 1897.
M361929
INTRODUCTION.
IT has long been known that the little island of Heligoland,
in the North Sea, is a spot especially favoured as a place of call,
by passing birds during their long migrations to and from their
breeding grounds. From time to time items of news, in the
shape of short notes, relating to the island, or the account of
a visit made by some enterprising ornithologist, have appeared
in the current ornithological journals, from which some idea of
the marvels of the place might be gathered. But at no time
has any attempt been made by a resident on the island itself,
to give a detailed account of the volume and character of the
migratory phenomena to be witnessed there. It has, however,
been no secret that one, with whose name that of Heligoland has
long been associated Herr Heinrich Gatke, has been for many
years accumulating material for such a work.
The appearance of "Die Volgelwarte Helgoland," printed in
the German language, some four years ago, was hailed with
universal welcome, and in response to a unanimous demand an
English translation was published early in 1895.
In a volume replete with interest, special prominence will be
found attaching to the author's opinions expressed in the leading
chapters relating to the direction, attitude, velocity, order, guid-
ing power, and meteorological conditions affecting the migratory
flight. The remainder of the work being chiefly occupied by
notes on the various species visiting the island, under their
separate headings.
No one has perhaps more closely studied, or had better
opportunities for the observation of the different phases of
VI.
migration, than the veteran author ; and the results of his
fifty years or more of labour, as now presented to the notice
of the ornithological world, are eloquent testimony to the untiring
zeal and energy of an accomplished field naturalist.
The opinions he expresses, on the special department of
ornithological science, for the study of which Heligoland is so
pre-eminently adapted, will naturally have the greatest weight
with all, and some in their admiration for the veteran observer
have formed the opinion, that all, or nearly all of our previous
conceptions, as to the direction, attitude and velocity of the
migratory flight, will have to be greatly modified or altogether
abandoned in favour of those he sets before us.
In the study of so complex a subject as the why and whither
of the migration of birds in general, much diversity of opinion
is naturally to be expected, and whilst the views of Herr Gatke
are entitled to the respect his' long experience demands, it will
not be surprising perhaps, if others find, in the observations
which he presents to our notice in support of the conclusions
at which he has arrived, evidence which may just as readily be
urged in favour of results quite as different.
In estimating the value of his various theories, it must not be
forgotten that they are based on observations conducted in
a very limited and somewhat exceptionally situated area ; outside
this area his personal experience seems to have been very small.
THE MIGRATION OF BIRDS
A CONSIDERATION OF HERB GATKE'S VIEWS.
ERRATA.
Page 2, line 10, for "attitude" read "altitude."
,, 19, ,, 16, for " Anglica " read " Anglia."
28, 7, for "west" read "east."
32, 21, for "Ochotok" read " Ochotsk."
,, 118, ,, 24, delete "may."
,, 131, ,, 18, for "parties" read "partner."
the general opinion Held bylhe majority ot naturalists.
This chapter also contains his remarks on the character or
breadth of the migration front, in which the flight is performed.
As the two subjects are intimately connected, his observations on
both may be conveniently examined at the same time.
It has been previously more or less generally assumed, that the
direction of the migratory flight in spring and autumn is approxi-
mately between the points of north and south. Whilst Herr Gatke
fully recognises a movement of this description it seems to him, as
may be gathered from his constant references, to be quite over-
shadowed in importance by an east to west flight or the reverse
1
VI.
migration, than the veteran author ; and the results of his
fifty years or more of labour, as now presented to the notice
of the ornithological world, are eloquent testimony to the untiring
zeal and energy of an accomplished field naturalist.
The opinions he expresses, on the special department of
ornithological science, for the study of which Heligoland is so
pre-eminently adapted, will naturally have the greatest weight
with all, and some in their admiration for the veteran observer
have formed the opinion, that all, or nearly all of our previous
THE MIGRATION OF BIRDS
A CONSIDERATION OF HERB GATKE'S VIEWS.
DIRECTION OF THE MIGRATION FLIGHT.
H AFTER I., though interesting, is to all intents and
purposes a diary, and as a whole calls for no
special comment. Such items as it contains,
which are of exceptional value, can, therefore,
readily be referred to as occasion may demand.
In a detailed examination of the whole work it will be convenient
to follow the author in his arrangement of the various chapters
relating to the different phases of the migratory movement. His
theories on the direction of the migration flight expressed in
Chapter II., which next claims the attention of the reader; will be
found of especial interest as they, to a great extent, controvert
the general opinion held by the majority of naturalists.
This chapter also contains his remarks on the character or
breadth of the migration front, in which the flight is performed.
As the two subjects are intimately connected, his observations on
both may be conveniently examined at the same time.
It has been previously more or less generally assumed, that the
direction of the migratory flight in spring and autumn is approxi-
mately between the points of north and south. Whilst Herr Gatke
fully recognises a movement of this description it seems to him, as
may be gathered from his constant references, to be quite over-
shadowed in importance by an east to west flight or the reverse
1
2
according to the season of the year. Indeed, he frankly con-
fesses that not a single bird is observed to adopt the former direc-
tion in arriving at, or departing from the island. It appears,
therefore, that he is only driven to the admission that many
species must of necessity migrate between the points of north
and south by a consideration of their geographical distribution.
It will, perhaps, be convenient to first consider the evidence
he presents in favour of this east to west flight. Before doing
so, however, it will be necessary to examine his theory relating to
the manner in which the travelling hosts of birds perform their
annual migrations. On p. 24 he writes: "The predominant
mode in which the migratory movement is performed is in a
broad front or migration column, which in the case of species
migrating to the west, corresponds to the latitudinal range of
their breeding area, and in those migrating southwards, to the
longitudinal extent of their nesting stations." It might be
inferred from this, that the author wishes to convey the impres-
sion that there are many migratory streams of birds travelling
east to west or north to south, but still leaving numerous wide
gaps in the advancing rank. That this, however, is not his inten-
tion, is pretty evident from his remarks on the migrations of the
Yellow-browed Warbler. On p. 30 he writes : " This bird ap-
pearing in Heligoland in favourable weather regularly every
autumn, two, three or more individuals being frequently observed
in one day, it surely ought also to occur in Germany with equal
regularity and in fairly large numbers." And again, on p. 33,
writing on the east and west migration in general, he remarks:
" In this long wave of migration, however, each of the many
hundreds of species which compose it, does not follow a migration
route, more or less narrowly limited of its own, but all on setting
out from their breeding area take up a westerly course which,
within the latitude of their nesting relations, they pursue to its
final goal " More to the point still are his remarks
under the heading of " Exceptional Migration Phenomena." In
discussing the question as to the justice of treating the Siberian
species which have occurred in Heligoland as erratic wanderers,
or otherwise, he writes (p. 118), "When we consider, as we are
undeniably entitled to do, that the large number of individuals of
species from far eastern regions, which are met with in Heligo-
land, must stand to the quantity of these erratics passing through
the whole of Central Europe every autumn, in the same relation
as the size of this island does to that of the continent." There-
fore, if in Heligoland alone from eighty to one hundred examples
of the Yellow-browed Warbler, have been shot or seen during the
last fifty years, it follows that the same species, but in proportion-
ately greater numbers, must also have appeared in Germany or
other parts of Europe during the same period.
The above extracts make it sufficiently clear that the author
wishes his definition of a broad migration column to be taken
in its most literal sense.
In comparing the area of Heligoland with that of Central
Europe, one naturally only compares the area of the former,
with a like area occupying the same longitude in the latter, as
the flight is supposed to travel east to west. Otherwise the
same individuals would be liable to be enumerated over and
over again at various different points. But if we are to apply
the before-mentioned theory to the rarer species, we are surely
entitled to do the same in the case of the commoner ones.
To fully realise the significance of such a theory, we have
only to take Herr Gatke's estimates of the numbers, comprising
the flocks of Hooded Crows, Starlings, Skylarks and others,
which pass the island, and multiply them by the vastly greater
extent of Central Europe in comparison with Heligoland, to
find that the results are something incredible and altogether
impossible. It must not be forgotten, too, that migration for
the most part, in the opinion of the author, takes place at
altitudes beyond the powers of ordinary vision, and that such
of it that comes within our cognisance is due to disturbances
of the normal flight. It is only fair to mention, however, that
the above-named species are amongst the few which usually
perform their journeys at a very moderate elevation. There
still remain the great majority, however, whose normal flight
is performed at heights beyond our vision.
As an illustration of what in Herr Gatke's idea is the breadth
of the migration front, his own words may be quoted. He writes
as follows : "In the case of the most different species, and in
districts so widely separated as Central Germany, Heligoland,
the eastern coast of Great Britain including the Orkney and
Shetland Islands Norway, up to a latitude of 70 N. in Finmark,
the same results as to the direction of the migratory flight have
been obtained. The latitudinal range of this migration front
covers a stretch of no less than 960 geographical miles . . ."
When it can be shown, as it undoubtedly can, that the breeding
range of certain species which according to his theories migrate
east and west entirely covers this distance, then, after also
taking into consideration the estimated numbers of these
species migrating past Heligoland alone, the full significance
of his theory of a broad migratory column corresponding to the
latitudinal area of the breeding range will be fully appreciated.
To return now to his views on the direction of the migra-
tory flight. " Direct observations in Heligoland," he remarks,
" either from watching the flight of passing migrants by day, or
by noting their call-notes during the night hours, have established
the following main results with regard to the direction of the
migration flight, viz., that in autumn the migration proceeds
from east to west and in the spring in the opposite direction.
Further, that in the cases of all the species and individuals noted
on the island, these courses are rigidly maintained during the
passage, and such rare deviations as do occur never extend
beyond one or two points of the compass. Not all birds, how-
ever, reach their winter destinations by an autumn passage
proceeding in this simple westward direction. Many on the
other hand are sooner or later obliged to turn southwards in
order to reach the lower latitudes in which their winter quarters
are situated ; in the case of some species the original direction of
flight is maintained throughout the whole immense stretch of
road from the eastern countries bordering the Amoor river to
the west of Spain." Herr Gatke here seems to have overlooked
the fact that there is a difference in the latitude of the Amoor
Valley and the west of Spain of ten degrees, or say seven
hundred miles, but of course in so long a journey this does
not proportionately amount to much. A flight, however,
between these two points can hardly be said to be performed
in a rigidly maintained east to west direction.
The words, " sooner or later," referring to a southward turn,
in the above paragraph, are very indefinite. This is unfortunate,
as it is plain, what a vast difference this turn must make in the
numbers of birds which would pass Heligoland, if it takes place
before the various flights reach the latter locality. To the
writer, Herr Gatke seems to infer in other places that the
majority do not travel southwards until they have crossed over
the North Sea to the coasts of Great Britain ; though there may
be a few exceptions to this rule.
Now there can be no reason for doubting that a vast number
of birds during their flight past Heligoland in the autumn, are
actually seen travelling in the direction pointed out by Herr
Gatke, and that their flight between these points can also be
traced over a limited distance both east and west of the island.
But a flight which has only been proved to trend in an east and
west direction over such a comparatively small proportion o
the whole journey, can hardly be held to be sufficient evidence
that its original direction, from its commencement to its arrival
at the latter locality, has been so rigidly or even approximately
maintained as Herr Gatke endeavours to prove. As to the
extreme view expressed above, that certain species perform a
flight which is maintained in this direction from countries
bordering on the Amoor to the west of Spain, there is to the
writer, only the migrations of one species, viz., Richard's Pipit,
that can be pointed to in support of such a theory, and the far
eastern origin of the individuals which reach Heligoland, will be
found, later on, to be open to doubt.
We are not expressly told what are the species which adopt
this east to west line of flight, though they are said to amount
to many hundreds. It is, however, possible to gather that
amongst the most important are the following: Buzzards,
Starlings, Hooded Crows, Books, Jackdaws, Larks, Swifts,
Plovers, Curlews and Geese. These species are mentioned on
p. 25, and God wits, Oystercatchers, Greenshanks, Sandpipers
and Thrushes are enumerated in addition on p. 30. This list,
however, leaves the remainder of the " many hundreds " men-
tioned on p. 33 to our imagination. It may be here pointed out
that the majority of the smaller species, such as the Bluethroat
and other warblers, Wagtails, Flycatchers, Chats, &c., arrive and
depart from the island in a manner which precludes the possi-
bility of realising in what direction they are travelling at all.
On p. 37, however, we are also told that the direct north and
south flight is peculiar to a large number of species (though it
must not be forgotten that none are said to be seen to adopt this
line of flight), more especially such as have their breeding
quarters in high northern latitudes. In the face of this remark
are we to eliminate from the above list the following, or not ?
Shore Lark, Grey Plover, Dotterel, several species of Geese,
Bar-tailed Godwit, Greenshank, Dusky Eedshank, Green Sand-
piper, Wood Sandpiper, Little Stint, Knot, Sanderling, and a
few others. We know also that many of these species are seen
during the migratory periods on both coasts of Scandinavia and
also in the Baltic, and we should expect numerous flocks from the
latter localities to touch on Heligoland. It must not be forgotten
too that the breeding ranges of most of the species recorded as
visiting the island, extend far to the north of the latitude of the
latter. As instances, the Kedwing, Fieldfare, and Hooded Crow
may be mentioned. In considering from what regions the enor-
mous flights passing Heligoland are derived, these facts are of the
utmost importance. It is a pity, therefore, that the author is
not more definite in his remarks as to the particular species
following this east and west route, especially as some already
mentioned are found during the winter season on the Mediter-
ranean coasts. It would be interesting in the light of this theory
to learn how these birds are supposed to reach the latter
locality.
It may here be as well to quote Herr Gatke's definition of
what he terms migration proper, or normal migration. On p. 46
he remarks " Here I ought to remind the reader, that when
I speak of migration proper, I mean those large extensive
movements which, on the one hand in autumn, conduct our
migrants from their breeding homes to or very near to their
winter quarters in one uninterrupted, and for the most part
nocturnal flight ; and on the other hand, in spring, convey them
in the opposite direction from their winter quarters to their
breeding haunts the uninterrupted continuity of the flight being
still more marked in this latter phase of the migratory pheno-
menon." From the above passage, read in conjunction with
others on the altitude and velocity of the migratory flight, it
will be clearly evident that the author's theories on the direction
of the flight are based on observations made, when this migration
proper has been interrupted and has therefore become in the
light of his remarks, at any rate disturbed; but we may fairly
assume that the direction is not affected in any case. Before
going any further it may be as well to take a brief glance at
the total number of species enumerated by Herr Gatke, as
having occurred on the island. A convenient summary, by the
late Henry Seebohm, appeared in the Ibis, vol. iv., 1892, pp.
1-32, and will be found sufficient for the purpose.
The total number known, or supposed to have visited
Heligoland, is 396 (one or two more have been added since the
publication of Herr Gatke's work). Of these some forty or more
are admitted into the list, on evidence not quite conclusive. But
if we remember that so many of the inhabitants of Heligoland
are familiar with all the usual visitors, we shall not err, perhaps,
in attaching more credence than usual in the case of these reputed
occurrences, especially such as have the endorsement of Herr
Giitke. At the same time one may be perhaps excused a feeling
of envy towards Aeuckens, who possesses a memory which
enables him, on the skin of a Warbler being submitted to his
notice, to declare the species of the latter identical with the
mutilated remains of another which passed through his hands
some twenty-seven years previously. Seventy-five other species
have been shot only once, though in a few instances other
examples have been reported as seen near enough for identi-
fication. There still remain some 280 species which pass with
greater or lesser regularity both in spring and autumn. A truly
marvellous number if Herr Gatke's theories are borne in mind,
and the small area under notice is not lost sight of. The
total European avi-fauna, including Neartic and other stragglers,
amounts to, in round numbers, 600 species, so that Heligoland
can claim fully two-thirds.
In considering Herr Gatke's theory of a rigidly preserved
east to west flight, it will be useful to learn what species have
8
reached the island which are not yet known to breed on the
western side of the Urals, and to also learn in what numbers
they have appeared.
As the result of upwards of fifty years' observation, we find
the following have been recorded :
Geocichla varia. Thirteen examples caught, most of them
in September and October. Seven or eight others seen.
Geocichla dauma. An example in Lund Museum which may
have been obtained on Heligoland.
Turdus Fallens. A bird seen June 3rd, 1881, supposed to
have been of this species.
Turdus fuscatus. A young example caught in 1880.
Turdus ruficollis. A young bird caught in November, 1843.
Turdus atrigularis. An adult male once seen.
Phylloscopus fuscatus. A bird supposed to have been of this
species seen in October, 1876.
Phylloscopus superciliosus. Seen about eighty times during
fifty years. More than thirty examples shot.
Phylloscopus proregulus. ODC killed October, 1845. A
second seen October, 1895.
Phylloscopus coronatus, One killed October, 1843.
Phylloscopus viridanus. Three shot.
Phylloscopus nitidus. One shot 1867.
Hypolais caligata. One shot September, 1851.
Locustella certhiola. One shot.
Cinclus Pallasi. Supposed to have been seen twice.
Saxicola morio. Two shot (this is, more correctly speaking, a,
south-eastern species).
Anthus Eichardi.K few in spring, pretty numerous in autumn.
Alauda sibirica. Two shot.
Alauda tartarica. One shot.
Emberiza pityornis. One caught.
Emberiza luteola. Two birds seen are supposed to have
belonged to this species. (This is also more of a south-eastern
species).
Parus kamschatkensis. An example seen by Herr Gatke, but
not obtained.
Charadius fulvus. Three shot.
9
Charadius caspius, Two shot, two supposed to have heen
seen.
A total numoer of twenty-four species. On the face of it this
appears to be a remarkable record for so small an area. But out
of the whole list only two can be looked upon as regular visitors,
viz.:
Phylloscopus super ciliosus. Average visits for fifty years, two
per annum.
Anthns Richardi. Fairly regular in spring, occurring in some
numbers in the autumn.
Of the others Geo. varia occurs on an average once in two
years. So far from the rest of Central Europe having produced
the foregoing species in numbers proportionate to its vastly
greater area, the exact converse is the case, and that these rare
birds in such theoretical abundance have escaped notice, is highly
improbable. This especially refers to the cases of Eichard's
Pipit and the Yellow-browed Warbler. Several other species are
included in the European avi-fauna on the strength of single
examples having been obtained on Heligoland alone. Of the
remainder of the list, one or two, have been included on the
evidence of supposed captures before Herr Gatke's time. About
a third of the whole number have only occurred once. What the
many other species from eastern Asia are which visit Heligoland
in such large numbers every autumn (p. 33), one would be
interested to learn.
If we take away the evidence of the far eastern origin of the
vast nights of birds annually passing Heligoland in the autumn,
afforded by the regular occurrence of Anthus Richardi and PhylL
superciliosus , but little remains to prove that any species in such
distant countries, on setting out from their breeding area, take up
a westerly course, which they maintain until they arrive at the
coasts of western Europe and Spain. If the foregoing species men-
tioned, as only breeding east of the Urals, are not to be regarded
as accidental stragglers, then, one cannot help being struck by
the different manner in which Herr Gatke treats the occasional
appearance of certain others, whose breeding grounds are much
nearer Heligoland, but whose migratory flight, he admits, is per-
formed from 7iorth to south. These individuals, on the contrary,
10
are pointed to as evidence of the undeviating character of the
latter movement, their appearance on the island being described
as of the rarest, though like the Siberian examples several have
been obtained more than thrice.
So far, however, from treating the Siberian species as erratics,
though their normal line of flight is also admitted to be north to
south, they are supposed to be affected by some law or impulse to
abandon the route pursued by the vast majority of their fellow-
travellers, and to turn to the west by a voluntary act, which is
not to be interpreted in the light of an accident, but in another
place is explained as due to the prevalence of certain peculiar
meteorological conditions at the time of their departure.
It must not be forgotten, too, that the flight of these Asiatic
species, in common with the European, comes equally under the
definition of the "broad migratory column" as before described.
Many should, therefore, be found passing through or wintering in
western and southern Europe in considerable numbers.
In Herr Giitke's opinion, the lack of evidence that such is the
case is due to the fact that certain of them are so inconspicuous
in size and appearance that the chances are all in favour of their
escaping detection. This, he especially insists upon, is the case
with the Yellow-browed Warbler, which, he thinks undoubtedly
occurs in some numbers in Great Britain every year. In con-
sidering the chances of this contingency he overlooks one fact
however. This species has most often been obtained in Heligo-
land in the month of October. Now in Great Britain, at this
period of the year, all the other Phylloscopi will have already
retired to their winter quarters. The appearance of a solitary
example, therefore, would be sure to attract the attention of any
observer interested in bird-life, and probably lead to the detec-
tion of the stranger. The call-note, too, has been described by
Seebohm as quite distinct from that of its European congeners.
The case of Anthus Richardi is still more striking, though
this species has been far more frequently detected in western
Europe than the former. But, whereas, if by Gatke's rule the
Yellow-browed Warbler should occur in hundreds, Richard's
Pipit should be wintering somewhere in tens of thousands, or as
he puts it himself, in incomputable numbers, and that such a
11
fine species, with its loud clear call-note, should be overlooked
under such circumstances is simply incredible.
It will be seen at once that our acquiescence in the statement,
that we are undeniably entitled to assume that these Asiatic
species pass through central Europe in numbers proportionate to
the larger area of the latter in comparison with the area of
Heligoland, will depend in the first place on our acceptance of
the theory that their western flight is performed in a broad
column corresponding to the latitudinal extension of their
breeding grounds ; as their normal migrations are admittedly
north to south, and in the absence of confirmatory evidence, the
application of such a theory to these particular species seems to
be quite unwarranted.
In perusing the contents of Herr Gatke's work, one is being
continually struck with the high estimates he places on the
numbers comprising the migratory flocks of birds passing the
island.
Curiously enough it will be found, in the first place, that the
species which migrate from east to west in autumn are said
to amount to many hundreds (p. 33), and also that as many,
if not more, preserve a line of flight from north to south. As
the whole ami-fauna, of Heligoland only amounts to some 400
species, one is rather puzzled how to account for these large
figures.
It will be readily admitted that to arrive at an accurate
result in calculating the numbers of rapidly moving objects is
very difficult. It is equally difficult to arrive at a proper esti-
mate of the value we are to place on the author's computations.
In particular instances the reader can hardly fail to be struck
by evidence of the grossest, though no doubt unintentional,
exaggeration. This must perhaps be attributed to the artistic
element in Herr Gatke's nature. As an instance of this ex-
aggeration, the case of the Hooded Crow may be pointed out.
On page 64 he writes of this species migrating "in millions,
nay, billions " an impossible estimate in any case, but still
more incredible if we bear in mind his theory of a " broad
migration column," and if we are also to assume that this state-
ment refers to the neighbourhood of Heligoland alone. It is
12
doubtful if any species of bird exists in numbers approaching a
billion. It is perhaps hardly necessary to point out that for one
billion of Hooded Crows to cross a given longitude in the sixty
days which Herr Giitke assigns as the duration of the migratory
iiight of this species, it would be necessary for no less than six-
teen thousand six hundred millions to pass each day. It will
also be observed that Herr Gatke is not even content with the
singular number. Whatever the breadth of the migration column
may be, such myriads are inconceivable.
In the article on "The Guillemot" also, we have another
instance in which he allows his enthusiasm to run away with
him. Eef erring to this species on p. 578 he writes of " countless
myriads of birds swarming about in all directions in the air ;
equally innumerable long-extending companies are seen swimming
near and far upon the sea" an artistic description truly, but
on further reference to the text we find that these " countless
myriads " and " innumerable companies" resolve themselves into
some fraction of a breeding colony of only 2,000 birds.
These remarks are not intended in any hypercritical spirit,
but merely to serve as a warning to the reader not to attach
too great an importance to statements that such and such species
pass Heligoland in numbers which can only be derived from a
breeding-range extending throughout the whole of Eastern
Europe and Asia.
In presenting evidence of his theory of an east - to - west
migration, Herr Gatke has wisely called attention to the flight
of several species which are either conspicuous from their
abundance, or from special interest attaching to their history.
It will, therefore, be convenient to follow him in his remarks
on each of these species in turn.
Before doing so, however, it may be as well to ascertain what
portions of the continents of Europe and Asia we are fairly entitled
to consider as belonging to the east. Of course, if we are to include
all the vast territory lying to the east of the longitude of Heligo-
land, from the Mediterranean in the south to the Arctic Ocean in
the north, and in like manner throughout Asia, then the theory
of an east-to-west flight may be very easily accepted. But if,
on the other hand, and bearing in mind the author's definition
13
of a rigidly maintained westerly flight, we take as our standpoint
the latitude of Heligoland as constituting the only true east,
then all points north of this latitude must be considered as only
approximating to the east in lessening degree, until at last true
north of the island is reached in Scandinavia. The same
remarks, of course, apply to the south. It follows, therefore,
that birds breeding in the north of Europe, and which may
happen to pass Heligoland on autumnal migration, must travel
in a direction more or less partaking of a direct southerly
character, even should they at the actual time of passage be
observed to be travelling due west. According to Herr Gatke,
however, the southward turn is only adopted towards the end
of a long westerly flight.
If we adopt, however, the definition of the east in its narrowest
sense as we might not unreasonably do in the light of the
author's remarks on the rigidly-conducted line of flight it follows
necessarily that any species migrating from the east, and adhering
to this course until it reached the longitude of Heligoland, will
only be observed at the latter locality if the latitude of its nest-
ing station corresponds with that of the island. "All on setting
out from their nesting stations take up a direct westerly course,
which they pursue to its final goal," he writes (p. 33). This is
an important point in considering the undeviating character of
the flight, as described by Herr Gatke, and in face of the enor-
mous numbers of birds annually recorded as passing his observa-
tion. For are we not told to use his own words that at Heli-
goland migration takes place in " extraordinary and unexampled
grandeur" (p. 4). If we accept the theory of a broad migratory
column, advancing due west from regions in the far east, we
should naturally expect to find, in like manner, birds passing
other points to north and south of the island in equal abundance.
These remarks especially refer to a well known species, viz.,
the Hooded Crow. The migration front of this species has on
one occasion, according to the author, been known to cover a
longitude of thirty-six miles in the immediate neighbourhood of
the island, and possibly further still. But this distance is insig-
nificant in comparison with the latitudinal extent of the breeding
range. Eoughly speaking, the latter includes Scandinavia and the
14
greater part of Europe east of the longitude of Heligoland, extend-
ing as far north as the limits of forest growth, and about as far
south as lat. 48 ; colonies also exist to the west and in north-
eastern Africa; but it is not necessary to take the latter into
account at the present juncture. Writing on the Hooded Crow,
Seebohm remarks : " Though the area of its distribution is
intersected by the narrow belt of Carrion Crows, which connects
the East Siberian colony with the Turkestan colony, and the
latter with the west European colony, it cannot be said to be
discontinuous. On the continent the Hooded Crow is found
throughout Europe east of long. 10, and in Asia extends north
of Turkestan as far as the valley of the Yenesay. . . . The
Scandinavian birds migrate to Holland, Belgium, and Northern
France, and even to England, in winter; and many of the
Siberian birds, together with hybrids of every degree, winter in
Turkestan." Amongst the millions of this species which pass
Heligoland every year, many of which, in Herr Giitke's view, are
derived from regions in the far east, he has not detected any of
these hybrids alluded to by Seebohm. Now what a remarkable
fact it would be if the individuals breeding beyond the region
where the former are produced, when migrating to the west, were
not frequently accompanied by many examples of the latter.
In the absence of these hybrids, it appears very unlikely that
any of the great flights passing from Heligoland are really
derived from a breeding area in far Eastern Asia. It will be
observed that Herr Gatke assigns the Lena as the limit of this
breeding area. On the other hand, most authorities mention the
valley of the Yenesay.
Even if these hybrids were unnoticed by reason of their not
passing directly over the island, they would hardly escape detec-
tion on their landing on the eastern coast of England, which
Herr Gatke informs us is the next destination of the vast flights
which pass his observatory.
What numbers of so voracious a species as the Hooded Crow
any given area could support is very difficult to say. But if we
consider the great quantities of Books which find a thriving
living in a limited district like the Midland counties of England
where every village has its rookery we may perhaps not deem
15
it necessary to have recourse to a country extending beyond the
Urals to sustain even the millions of Herr Gatke, as he himself
suggests.
How are we to account for the accumulation of these vast
flocks, if we accept the theory that all on setting out from their
nesting stations travel in a rigidly maintained westerly direction
and in a broad column corresponding to the latitudinal area of
the latter? Except at the periods of migration the Hooded
Crow is not a particularly gregarious species, and though con-
siderable numbers may be present in a small district, yet at their
winter quarters small parties, rather than flocks, are met with
as a rule. With regard to the breadth of these flights, the most
that has been proved is, that on a certain occasion, viz., October
24th, L884, the present species, in company with Rooks and
Jackdaws, was observed to be passing over and near Heligoland
in vast numbers, and in a flight having an ascertained frontage
thirty-six or forty miles in extent, though we are not told this
was an unbroken front. Now no country, due east of Heligoland,
of this breadth, even if it extended as far as the Yenesay, would
have been large enough to have produced the millions comprising
this flight. Herr Gatke also further attempts to prove that
this migration front covered a vastly greater breadth. At the
same time, he writes, that an extraordinary migration was taking
place " over the North Sea, on the eastern coast of England and
Scotland up to the Orkney and Shetland Islands." On referring
to the "Report on the Migration of Birds for 1884," it will be
found that whilst there certainly was a large movement in
progress on the east coast of England, within or around a latitude
corresponding to that of Heligoland ; further north, however,
the numbers arriving were insignificant and not more than the
normal. In support of this statement those portions of the same
report relating to the east coast of Scotland may be quoted. On
p. 28 we read " In autumn, a more decided movement of
Hooded Crows (this in comparison with spring, when less than
usual were observed). Records from Sumburgh Head, North
Ronaldshay, Pentland Skerries, Girdleness and Isle of May (none
noted at Bell Rock) Decided rush between October
llth and 26th at Pentland Skerries (14th), and at Isle of May."
16
It will be observed that these dates do not altogether coincide
with those recorded at Heligoland.
Now let us also see what constitutes a rush on the east coast
of Scotland. Again quoting from the same source we find
" The numbers recorded are, on llth and 12th one shot by
J. A. H. B. ; no more till 23rd ; eighteen flying north (and
Books), forty on 24th, and forty on 25th, with one Carrion Crow.
Continued on 26th. Again in November, a number for some
days at Sumburgh Head on 10th ; also at Pentland Skerries
a few, and the indication of a rush at Isle of May, on 12th and
15th, flocks of nine and twelve having been seen on these dates."
Compared with the myriads recorded from Heligoland these
numbers are utterly insignificant. [Though too long to be
quoted here, the remarks of Messrs. Harvie Brown, and Cordeaux,
on the stretches of coast on the east of Great Britain most
favoured as points of arrival by immigrant birds will be found
especially interesting in connection with the theory that migra-
tion is performed in a broad front (see reports for 1885).]
It may here be remarked with reference to this rush of
Hooded Crows in October, 1884, that the chief lines of flight
were S.E. to N.W., E. to W., and S. to N.W., as observed at
various light vessels and lighthouses adjacent to the east coast
of England; thus showing if we grant the identity of the flocks
passing Heligoland with those arriving on our Lincolnshire coast
that the rigid east-to-west direction, which this flight is originally
supposed to have possessed, had undergone a certain amount of
deviation before reaching the latter locality.
The above evidence will perhaps justify our assumption that
over whatever breadth the migration front extended at the time
of its inception, it had become considerably contracted by the
time it reached our shores, and bore no adequate relation to the
latitudinal area of the breeding range. And with regard to the
general direction of the flight we cannot conceive that a district
thirty-six miles, or fifty miles in breadth, even if it extend to
the valley of the Lena, could produce the species in such great
abundance. Does it not follow, therefore, that at some period
of the journey, there must be concentration on to some common
fly-line of all the migratory individuals of this species, from
17
districts intermediate, between the north-east and east of the
latitude of Heligoland. If so, shall we be justified in calling
a flight, which under these circumstances would trend more
or less from N.B. to S.W. ; a rigidly preserved westerly flight ?
In suggesting a " concentration on to some common fly-line,"
it must not be inferred that this implies any special intention on
the part of the flocks to meet together with this purpose in view,
bub to point more to a fortuitous circumstance, brought about
possibly by the configuration of the country as the Hooded
Crow is a low flyer.
It is easy to see how this concentration may occur. If we
glance at the map of Europe we shall find that the land reaches
its highest northern latitude in Russia, at the extreme north-
eastern boundary of the continent, and that as we travel west-
wards from thence, the coast line, as far as the shores of the
White Sea, gradually falls away towards the south-west. If we
grant for the moment that the Hooded Crows breeding in the
regions above the arctic circle migrate due west from their
nesting stations and rigidly preserve this direction of flight, they
will sooner or later reach the shores of the Arctic Ocean. Now
we have no reasons for thinking that at any point in the far
north, they leave the land to migrate across the sea to the Kola
peninsula. If, however, this actually takes place, then a con-
tinuance of their journey would take them to the west coast of
Norway, where they must either turn south or cross the North
Sea, and their further flight, in this case, would tend either to
miss Heligoland altogether, or, at the most, to cross the island
in a north to south direction. It seems, however, far more
reasonable to suppose, that such migratory flocks which breed in
the far north still assuming that they take up a direct westerly
course would, on reaching the sea, follow the coast line to the
delta of the Dwina, where other flights, from lower latitudes,
would coalesce with them, and thus continue their further
journeys in company. A similar concentration may very well
take place at many points along the eastern shores of the Baltic ;
whether individuals in the first instance migrate due west or south-
west ; and we can thus see how the immense hosts observed at
Heligoland may be marshalled together. The flocks comprising a
2
18
migration conducted in a broad front, and travelling west, would,
on turning south at an identical longitude, naturally be converted
into a comparatively narrow flight, and bearing no relation what-
ever to the latitudinal area of the breeding ground. It seems
more probable that these migratory Crows would follow the
eastern shores of the Baltic in preference to making an attempt to
cross to the opposite coast in continuation of their westerly flight :
for, as has been pointed out before, if they still persisted in a
flight in the latter direction as far as shores of the Atlantic, they
would hardly be likely to touch at Heligoland at all. Birds are
very conservative in their habits, and there can be little doubt
that inheritance comes largely into play when the locality of their
winter home has to be determined. If we grant that the nature
of migration at its first inception is to-day best represented by
the intermittent movements of those species which may be said
to hang about the fringe of the severest cold, we can understand
that the habit of crossing wide seas, as is the practice of birds
at the present time, must have been a later development; not
from any lack of powers of flight, but more from a reluctance to
attempt a journey leading to some unseen and unknown goal :
indeed, the pioneers in a movement of this nature must, as far
as we can see, have first undertaken such a flight through an
accident or by force of circumstances, rather than design. We
cannot imagine birds to have been gifted with a sense which
enabled them to detect the presence of land in the far distance,
and beyond their range of vision at this early stage of the develop-
ment of the migratory habit. Thus the flights of Hooded Crows
are more likely at this early period to have followed the coast
line of such seas as they encountered, and have continued to do
so to the present day. According to Herr Gatke's view, how-
ever, it is not the sight of the sea which turns birds to the
south, though he does not tell us his reasons for coming to this
conclusion. In bringing forward evidence in favour of the far
eastern origin of these great flights of Hooded Crows, Herr Gatke
is apt to lay too great stress on the fact that their direct westerly
flight can be traced over a distance of six hundred miles, i.e.,
from the shores of Schleswig Holstein to the interior of England ;
but it can readily be proved that only a small proportion, if any,
19
of the vast hosts he alludes to, ever reach the latter country;
and even such as may do so, turn to the south soon after their
arrival on the east coast. But in any case a westerly flight of
some 600 miles is only a moderate fraction of the distance
between central England and the valley of the Yenesay.
With regard to the ultimate distinction of these hordes, it
seems to the writer, after considering all the evidence bearing on
the subject, that soon after passing Heligoland the great majority
turn towards the south or south-west, some passing inland into
Germany, and the remainder wintering in Holland, Belgium and
France, or, perhaps, still further south as examples have been
met with in Spain.
That any large proportion of these millions reach the east
coast of Great Britain which is the case, according to Herr
Gatke there is no evidence to prove. What would be the effect
in East Anglica of an incursion of a voracious species like the
present, in numbers approaching those observed at Heligoland ?
They could hardly fail to create a sensation, even if they were
distributed over the whole littoral between the Humber and
Thames. Certainly the species is observed in the late autumn
in considerable numbers in our eastern counties ; but there are
no records referring its appearance in even tens of thousands.
It is simply impossible that such huge numbers could escape
observation. Neither do Hooded Crows on reaching the coast
line pass very far inland to the extent Herr Gatke imagines.
The following remarks of his, quoted from p. 26, are based on
mere assumption. He writes : " Now the Eastern and Mid-
land counties of England cannot by any possible means afford
sufficient room for furnishing winter quarters to .the millions of
Hooded Crows, which every autumn pass this island across the
North Sea; and since, according to Eodd and Thompson, they do
not reach either the West of England or Ireland, ... it
follows that they must very soon after reaching England pass
across the channel to France." On p. 25 he further writes:
"The Hooded Crow does not get to the Western parts of Eng-
land, but turns to the South as soon as it reaches the central
portions of that country." These statements are rather contra-
dictory, too, after having previously quoted Mr. Cordeaux's
20
remarks, to the effect that the species still flies directly inland
to the west on arriving at the Hum her. For if they pass inland
in Lincolnshire, it follows that they must cross a wide district of
England before they can reach the Channel to cross into France.
There is also no evidence to show, nor any reason to suppose,
that they suddenly alter the character of their flight and pass over
the central parts of England at a great elevation, and thus escape
notice. For in the light of the author's theories on the altitude
of flight, this would mean a sudden change of meteorological con-
ditions immediately on their arrival ; and the Hooded Crow is
one of the few species which always fly low. That the present
species is seen in moderate numbers, crossing England from north-
east to south-west every autumn by certain well-known routes,
will be readily admitted ; but the evidence in favour of an
immediate turn to the South on their first making the land, all
points to its being the course adopted by the majority ; for very
large numbers (though not millions) have been observed following
the line of the sand hills due south, on the Norfolk coast, in com-
pany with Books and Daws (see Migration Committee's Eeport).
The Hooded Crow at its winter quarters seems to be a very aquatic
species, and is very fond of wading in shallow waters in search
of food. It appears natural for a species possessing these tastes
to hug the coast line as much as possible during its migratory
journeys, and in passing inland to follow the course of rivers
not as guides to its destination, but as convenient routes where
food can be readily procured when required. That all the Hooded
Crows observed in the eastern and midland counties reach us
via Heligoland is, however, very improbable ; for, according to
Seebohm, many individuals breeding in Scandinavia winter in
this country, and we should hardly expect Norwegian examples
to travel past the island on their journey here. Confirmation of
this may be found in the Migration Committee's Eeport, 1884,
p. 53, where it is recorded that: "During the latter half of
November the rush (of Hooded Crows) seems to have been con-
tinuous night and day" thus differing in character from the
migration observed at Heligoland, which ceases about 2 p.m. ;
" at the outer Dowsing light vessel on November 1st, 2nd and
3rd, a continuous rush N.E. to S.W., and also at other stations;
21
but in less numbers to November 15th. . . ." A continuous
rush N.E. to S.W. seems to point to the Scandinavian origin of
this flight. As will be seen later on Mr. Eagle Clark, in his
digest of all these light-house and light-ship records, has come
to the conclusion that direct migration from Heligoland to our
East coast only takes place on rare occasions. If the Hooded
Crows seen in Lincolnshire are identical with those passing the
former locality, they must reach us by a somewhat circuitous
route. This is important in view of the fact that Herr Gatke
bases one of his computations on the speed attained by migra-
tory birds on the identity of these flocks.
We are not told much about the return migration of the
Hooded Crow in spring; but we learn that the species passes
Heligoland, travelling towards the west, in rare instances at a
vast height, but usually at no greater elevation than 100 feet, and
in smaller numbers than those observed in the autumn; there
is also no evidence set before us to prove that the breadth of
flight is so great as at the former period. There will, perhaps,
not be much tendency on the part of the flocks to break up
until the eastern shores of the Baltic are reached ; any inclina-
tion to scatter, and thus present a broad migration front until
later in the journey, would be thus avoided at the time of passage
by the island.
After weighing all the evidence in favour of the far eastern
origin of these great flocks- of Crows, and the supposed westerly
course of their flight, one is inclined to agree with Herr Gatke
that the foregoing considerations have gone no further (or even
so far) than to prove that they have maintained a westerly flight
over a stretch of some 600 miles. But whether this is enough to
justify our assuming that all these countless hosts of wanderers
have regularly maintained this direction from the commencement
of their migration, is, in the light of the evidence adduced, very
much open to question.
In further considering the theory of a migration conducted
in a broad front, we pass from the evidence afforded by a very
common species to that presented by a comparatively rare one,
viz., the Honey Buzzard. We are also told that this species
furnishes further proof of a migration in a direction from the far
22
east to the far west. Whether the latter fact be true or not, the
acceptance of the theory that the migration is conducted in a
broad front corresponding to the latitudinal area of the breed-
ing grounds will be found to be very difficult. Indeed, it may be
at once remarked that the evidence of other observers quoted on
p. 28 by Herr Gatke all points to the opposite conclusion.
The spring migration of this species, as observed at Heligoland,
is described as being performed in very small parties, but in the
autumn almost always in assemblages of varying numbers, but
which sometimes during the first weeks of September, assume
considerable dimensions. An unusually marked migration
occurred on September 19th, 1858. This movement commenced
with small parties in the forenoon, and increased towards sunset
to one incessant stream of flocks of fifty, eighty, or even larger
numbers. These approached the island from the east and
disappeared from view in the far west, just as the majority of
species do. Now, though this migration, as regards numbers,
was abnormal and not likely to occur again for many years, yet
there is no reason to suppose that it was conducted in any but
the normal manner of flight. The author's theory of a broad
front should, therefore, still apply, as in the case of other
species.
On witnessing a phenomena of this nature, Herr Gatke might
well express his wonder as to how such extraordinary numbers
of an uncommon species had banded themselves together, but
perhaps he had in view his theory of the " broad front " when
he hazards the opinion that only the endless forests of Euro-
pean and Asiatic Eussia could have given birth to such a
throng. For we must assume, to be in harmony with the above
theory, that still greater numbers were passing other localities
both north and south of the island a fact impossible of realisa-
tion in the case of so rare a species without concurring in his
remark on the necessarily vast area requisite to produce such
multitudes ; and in the latter case one is also impelled to
ask What became of all this great host and in what country did
its constituents find winter quarters?
Though this migration was evidently of an exceptional
character as regards numbers, and perhaps akin in nature to that
23
of the Jay described elsewhere ; it seems impossible to realise
how so many of a rare species whose nesting stations must have
been scattered over a wide country can have come together
unless they had gradually concentrated themselves on to some
customary fly line. It may be surmised that many small flocks
had accumulated at some point where their further progress had
been delayed by unfavourable weather. Herr Gatke's description
of the flight seems to point to this small parties at first, then
larger ones, then a steady stream of flocks, and lastly the main
body in one continuous procession. Had an advancing column
of Honey Buzzards in a rank corresponding to the latitudinal
area of the breeding range suddenly set out from the Asiatic
forests to Western Europe, gradually augmenting its numbers
as it progressed, it could hardly fail to have attracted notice in
many parts, whereas in the present instance, Heligoland seems
to have been almost the only spot where such large numbers
were observed. On the theory of a direct east to west migration
many of this throng should have reached the coasts of Great
Britain unless a southerly turn was made soon after passing the
island. In the former country, owing to the persecution meted
out to all the larger birds of prey and other rare species, an
event of this nature could hardly have failed to have excited
remark. We know what has happened during the visitations of
Pallas' Sand Grouse.
If on the other hand these large flocks had become gradually
concentrated through the configuration of the country, the
following of river valleys or shore lines into a narrow stream
the chances of their escaping notice would have been vastly
increased, especially as their ultimate destination seems to have
been some part of North-Western Africa. It is well known that
the Honey Buzzard passes the Straits of Gibraltar in large
numbers every year (Irby). It is only evading the difficulty in
suggesting that a further westerly flight may have been con-
ducted at a great elevation and thus have escaped notice. It
has already been pointed out in the case of the Hooded Crow ;
that, such a change in altitude really means, according to the
author's theories, a sudden variation in meteorological conditions
necessitating an ascent to higher regions of the air. That in
24
Herr Gatke's view this migration of Honey Buzzards was con-
ducted in the normal way, i.e., in a broad front, the following
extract from his notes will illustrate. He writes, p. 29 :
"The fact that the Honey Buzzard does not reach Portugal
, also proves what has been already called attention
to, in regard to Hooded Crows, that it is not the sight of the sea
which induces birds migrating in a westerly direction to turn
suddenly south, but that this deviation forms, from no account-
able cause, the concluding stage of the westerly course of
migration. A similar phenomenon is presented by the same
bird in England. In that country the Honey Buzzard is met
with as a breeding species only in solitary instances, but arrives
in tolerably large numbers on the east coast during the autumn
migration. Such examples as originate from the northern limits
of their breeding zone in Europe and Asia, bring their westerly
flight to an early close in England, when, then turning south, they
pass, via Western France and Spain to their winter quarters in
Africa."
It will certainly be news to British ornithologists to learn,
that the Honey Buzzard arrives in tolerably large numbers on
the east coast during the autumn migration. Surely Herr Gatke
is thinking of the Bough-legged Buzzard. Furthermore, to the
writer, it does seem to be the sea that turns these northern bred
birds to the south, otherwise they would reach the Shetlands,
Orkneys and North of Scotland coasts rather than the east
coasts of England. If taken at all the turn no doubt actually
takes place in Scandinavia.
In further consideration of an east-to-west migration we may
now turn to another interesting, but more common species,
viz., the Shore Lark. As can be readily proved from pretty
conclusive evidence, this species within the last fifty years
has undoubtedly been extending its breeding range westward.
In the light of this fact its gradually increasing abundance
on passage at Heligoland is significant, for it is one of those
species occurring in great flights to which Herr Gatke attributes
a far eastern origin. With regard to its former breeding
range he has collected the following facts " According to
Pallas (" Zoogr. Eoss. Asiat.," pub. 1811), the bird was in
25
the last named year already distributed over the whole of
Siberia, but in 1835 had not been met with as a breeding bird in
Scandinavia." Now if Herr Gatke's contention is correct that
a great proportion of the Shore Larks passing Heligoland are of
Asiatic origin, as he describes 011 p. 32, it is a remarkable fact,
bearing in mind that the species had already spread over the
whole of Siberia, that this bird was at that particular period
unknown as a visitor to the island. It is still more remarkable
that not until ten years after the discovery of pairs breeding in
Eastern Finmark, viz., the year 1847, that examples were met
with in Heligoland in any numbers. " Since that time adds
Herr Gatke the Shore Lark has rapidly multiplied and it has
become one of the most common breeding birds in Lapland and
Finmark." Some idea of its abundance in Scandinavia even as
much as thirty or more years ago, may be gathered from
"Wheelwright's experiences. The latter observer states that
during his stay at Quickiock he secured about fifty examples
and could have obtained many more had he so desired.
Now what a curious coincidence must have taken place in
regard to the extension of the breeding range and the migratory
habits of this species if, as soon as it had become numerous
in a region lying to the north and north east of Heligoland,
whence its migratory flights might reasonably be expected to
carry it over the island that the Asiatic individuals should
suddenly develop a tendency to abandon their old winter
quarters lying to the south or south-east of their breeding
range and to seek new ones in the west or south-west of Europe ;
a district where we should only expect the breeding birds from
Northern Europe to find a winter home. In the light of the
evidence brought before us by Herr Gatke, if we accept his
theory of the far eastern origin of the large flights of this species
which now pass his observatory, this is really what must have
taken place.
The locality of the winter quarters of the Shore Lark is
involved in some obscurity, which Herr Gatke's speculations
will hardly tend to dissipate. After commenting on the enorm-
ous numbers comprising the above flights which in his opinion
can only be derived from a country far larger than the whole of
26
Northern Europe, he next calmly assigns them a winter home in
the comparatively tiny area of the mountain regions of France
and Spain.
Suppose for the moment we admit that Herr Gatke is correct
in assuming an eastern origin of these large nights of Shore Larks,
and we also try to trace their further westerly flight after passing
Heligoland. We shall find, as far as Great Britain is concerned,
that not until the period between the years 1860 and 1870, or
ten or twelve year after the first considerable numbers were
observed at the former locality, that flocks of any importance (say
comprising fifteen to twenty birds) were observed on the east
coast of England, though the species, in the meantime, since its
first occurrence, was yearly passing Heligoland in ever-increasing
abundance. It will at once be apparent that, as in the case of the
Hooded Crow and Honey Buzzard, though more markedly in the
present and latter species, that only an insignificant proportion
cross the North Sea, as indeed is the case at the present day.
If the facts were otherwise, they could hardly fail to come under
observation, and it is only evading the difficulty to suppose that
these individuals suddenly alter the altitude of their flight and
pass over at a great elevation (see p. 367). Larks, as a rule, on
migration, as Herr Gatke himself tells us, fly comparatively low,
and we may take it for granted that this is especially the case
in passing over large areas of land. Even if these Shore Larks
really increased the altitude of their flight in travelling across
England, we should expect them at times to meet with adverse
meteorological conditions, and on such occasions we might
reasonably look for many stragglers or even small flocks in
inland localities. But up to the present time this species has
been a bird of the rarest occurrence in the latter country away
from the coast.
The evidence of other observers quoted by Herr Gatke
(pp. 32, 366) does not lessen the difficulty of accepting the
theory of an east- to- west migratory flight on the part of the
Shore Lark. He writes: " These birds arrive in East Finmark
from the east and are consequently known there under the name
of Bussian Snow-Buntings. Collett says (see Dresser IV.) that
they travel from Norway east, and thence down through
27
Sweden, and are seen in lower Norway only in exceptionally
rare instances. In Southern Sweden they unite themselves
with those coming from Asia, hence have arisen the innumer-
able hosts seen in Heligoland within the last decades." What
evidence there is that the flocks met with in southern Sweden
come from Asia, is very difficult to see; but the case of those
migrating from Norway a latitude due North of Heligoland
affords a striking instance of how easily a species migrating
really north to south, or south-west, may be erroneously
regarded as one performing the whole journey in an east-to-
west direction, simply because, at the moment of observation,
it may be passing a particular locality in the latter line of flight.
It may even be the case that those individuals exceptionally met
with in Southern Norway, may be identical with the birds which
reach our eastern coasts, for it is difficult to see to what other
country their journey, if any, further prolonged, would carry
them.
There is not much to be learnt with regard to the theory of
a " broad front " from the migrations of the Shore Lark, as its
breeding grounds, for the most part, lie above the limits of forest
growth ; but Herr Gatke apparently has the idea in view when
he writes respecting flocks from Asia being met in southern
Sweden by others from the north of Norway. As he points out
a southern turn must be taken by flocks breeding east of the
Baltic, up in the far north, otherwise we should expect to find
the species in greater abundance in the most northern parts of
Great Britain, i.e., in the Shetlands, Orkneys and north of
Scotland, or perhaps still further north, away in the Faroes and
Iceland. It seems, however, to be carrying the theory of a
westerly flight to an absurdity in suggesting the probability of the
species occurring as an occasional visitor from Europe on the
Atlantic coasts of America. Herr Gatke seems to think that the
Shore Lark must have displayed, even from its origin, a strong
inclination for a westerly autumn migration, for otherwise, it
could never have got across into Asia and finally to Lapland and
Finmark. What he means by the remark " even from its origin "
is not easily discernable, unless he intends to convey the idea that
as the evolution of the species progressed, a supposed innate
28
desire to migrate westward was also developed, until it found
vent in a voluntary move into eastern Asia.
It is curious to read on p. 122 that, whereas, all species in
Western Europe have a strong disinclination to migrate to the
east, this objection ceases to exist on the American shores of
the Atlantic. The Nearctic birds are said to evince as strong a
tendency to turn to the west, as Asiatic species are said to be
given to migrating in the reverse direction. The northern Blue-
throat occasionally appears in Alaska. Are we therefore to
assume a tendency on the part of this species to migrate in the
opposite direction to the Shore Lark ? In the case of the latter
it will be noted that Herr Gatke writes of a westerly autumn
migration. It seems hardly likely, however, that a species whose
normal flight must have been north to south in its original home,
should have suddenly developed a tendency to migrate westwards
on first establishing itself on the Asiatic continent ; a proceeding
more likely to have led to the extinction of the colonists than to
their future increase. Is it not more probable that these first
visitors to Asia accidentally * found their way thither in the
spring, and after having bred there, wintered in China or some
country in the south-east ; returning again to their new breeding
homes the following year, being guided in their movements by
surrounding species ? In passing it may be noted that the Shore
Lark breeds fairly numerously in Novaya Zemlya. A westward
autumnal migration would hardly have colonised this locality,
especially in view of Herr Gatke' s theories as bo the direct
manner in which birds that adopt this course return to their
breeding grounds in the spring (see p. 42). With regard to the
latter theory, the present species so far from adopting a straight
course from its winter quarters to its breeding grounds, passes
Heligoland at this period in considerable numbers. Wherever
these last are derived from, it is evident that their line of
flight is circuitous ; as in no locality so far south as the latitude
of the island is the species known to nest. It is a curious fact
that the Lapland Bunting, a species having a similar distribu-
tion in the breeding season to the Shore Lark should be of so
uncommon an occurrence in Heligoland, especially as of late
years considerable flocks have migrated to our east coast. But
29
I the latter fact only emphasises the opinion that much of our
| east coast migration is quite unconnected with that occurring
in the former locality. As the Lapland Bunting also breeds
; throughout Northern America, its spread westward has probably
been accomplished in a similar manner to that of the Shore Lark.
But those individuals breeding in North- Western Europe seem to
have a tendency to migrate in the autumn to the south-east
rather than to the south as, no doubt, was the habit of the Shore
Lark until comparatively recent times.
From species having a breeding range extending throughout
Northern Europe and Asia, we must now turn to two others,
which have up to the present, not been detected nesting in the
former continent, viz., the Yellow-browed Warbler and Eichard's
Pipit, to both of which Herr Gcatke makes very frequent allusion.
Though neither have been known to breed, on unimpeachable
evidence within the boundaries of Europe, it cannot be said with
truth that the full extent of their breeding areas is at all
completely known.
In the case of the Yellow-browed Warbler, the late Henry
Seebohm was the first to take authenticated eggs in the valley
of the Yenesay, in lat. 66. He found the birds breeding up to
about lat. 68, as we learn from his work " Siberia in Asia."
Since his memorable journey little or nothing has been added, to
our knowledge, of any further westward extent of its breeding
range ; but that the valley of the Yenesay forms the limit is very
unlikely. It must not be forgotten that several Asiatic species,
such as the Petchora Pipit, Siberian Stonechat, Yellow-headed
Wagtail, Siberian Chiff-Chaff breed in North-Eastern Europe;
the same observer having met with them in the valley of the
Petchora. It seems, therefore, not unreasonable to suppose that
the Yellow-browed Warbler breeds very near to, if not within,
the European portions of the Russian empire. In any case, Herr
Giitke is hardly justified in alluding to it as " a little East Asiatic
species," or as a species from the extreme east of Asia (p. 77)-
The Yenesay in lat. 66 is within 700 miles of the Urals.
Such a description seems to quite over-state the facts of its
distribution. A similar exaggeration is apparent in the author's
remarks on its occurrence in Heligoland. On p. 288 he writes :
30
" The migration of this Warbler commences in Heligoland
during the last ten days of September, and continues until the
end of October. On several occasions the bird has been met
with as late as the beginning of November." And, again, on
p. 43, he further states that this bird may be met with almost
daily in favourable weather during the autumn migration. From
these assertions it might be inferred that the bird appeared during
this period, more or less every day. But when the records of
the examples shot and seen, or reputed to have been seen, are
examined, it will be found that the average occurrences have not
exceeded two examples per year. It is true that in certain
years as many as half-a-dozen have been reported ; but, on the
other hand, at certain times none have appeared at all. It may
also be the case that, when the species has been most numer-
ously noted, that the same individuals have been reported more
than once, as in one or two instances the records refer to con-
secutive dates. In any case, the average occurrence of two
individuals per year, of an Asiatic species whose distribution is
very imperfectly known, furnishes but little proof of a general
east to west autumnal migration. As an instance of how our
knowledge of the geographical distribution of these smaller spe-
cies may be at fault the case of the Sedge Warbler may be
pointed out. Until Mr. Seebohm visited the Yenesay valley this
noisy and conspicuous species was supposed not to breed east of
the Urals, except in Western Turkestan. Commenting on this
fact, Mr. Seebohm pertinently asks, " Where do the Yeuesay
Sedge Warblers find a winter home?" No rigidly adhered to
north-to-south or east-to-west line of flight would convey them
to Africa, the only locality known at present. Again, even so
experienced an observer as this gentleman overlooked Pallas'
House Martin on his Yenesay journey. It was not until he
returned home that he discovered he had been amongst thou-
sands of this species.
The contemporary records of the appearance of the Yellow-
browed Warbler relating to other parts of Europe, throw some
light on the theory of migration being conducted in a broad front.
According to Herr Gatke's views, the species should pass through
central Europe in numbers proportionate to the vastly greater
31
extent of the latter country, in comparison with the area of
Heligoland. That such is not the case has already been shown,
and also that the numbers obtained on the island exceed the
total captures for the whole of the former country. As the lati-
tudinal area of the breeding range extends beyond the Arctic
circle in the north, we should expect, if individuals from those
portions of the latter exhibited a tendency to turn to the west
immediately on setting out from their nesting stations, in the
manner described by Herr Gatke, that the majority of the occur-
rences in Europe would have been recorded at points far to the
north of Heligoland. As a matter of fact the evidence all points
to a probable considerable flight to the south before the western
turn takes place, assuming that the Heligoland examples come
from such a distant region. It must not be forgotten, too, that
the normal migration is from north to south; or south-east
with those individuals known to nest the nearest to the Euro-
pean boundary. If, therefore, the examples occurring in Heligo-
land are derived from the Yenesay, or some region further east,
and not, as is more probable, from a locality very much nearer
to or within North-Eastern Eussia ; then the so-called westerly
migration seems to be conducted in a comparatively narrow
front, and not in a column at all related to the latitudinal
extent of the known breeding area.
Another theory as to the manner in which these Asiatic
stragglers reach Heligoland may be here advanced. It is a well-
known fact that many species of birds, whose breeding-ranges
are confined to the South or Central Europe, are occasionally
captured many hundred miles to the north of their customary
haunts. The Roller, Bee-eater, Golden Oriole, and certain
warblers, may be pointed to as instances ; some of them having
been met with in the Shetlands, and the Oriole as far north as
the Faroes. It cannot be doubted that similar straggling goes
on over the whole of the Palaearctic region. There seems to be
no difficulty in imagining individuals or small parties of Yellow-
browed Warblers, Siberian thrushes, and others, after passing
the summer in some haunts to the north-west of their customary
breeding range, joining those large flights of other species whose
normal migrations carry them over Heligoland.
32
After considering the above evidence, it may be asked in
conclusion, " Does the migration of the Yellow-browed Warbler
whose appearance on Heligoland is said in another place to be
due to the prevalence of meteorological conditions of a peculiar
nature, and therefore more or less accidental, afford proof of any
value that the normal course of migration is due east to west, and
that many other species having their homes in far Eastern Asia
travel to their winter quarters by an identical route ?
In the case of Eichard's Pipit to which Herr Gatke also
refers so very frequently, we have another species whose breeding-
range is very imperfectly known, and we find the same ten-
dency on the part of the author to refer to the extreme eastern
limits of its known extent, as the district from which the remark-
able nights passing through Heligoland are derived. To the
writer there seems to be absolutely no need to assign the
countries east of Lake Baikal and those bordering on the Sea
of Ochotsk as the summer home of these particular individuals.
Herr Gatke seems to have quite overlooked the fact that the
late Hy. Seebohm found this Pipit very common at Yenesaisk,
some 800 miles nearer Heligoland than Dauria and 1,600 miles
nearer than the Sea of Ochotok. True, he did not take a nest,
but then at the time of his visit the breeding season was over,
and if it is objected that the individuals he met with were
already on migration, then their presence at Yenesaisk throws
considerable light on the leisurely manner in which the species
performs its flights. To the writer there can be little doubt
that Eichard's Pipit breeds much nearer to Europe than even
Yenesaisk and possibly within its boundaries, for it seems highly
improbable that any species could have acquired the habit of
crossing half of the continent of Asia and the whole of Europe in
search of a winter home. Like the Yellow-browed Warbler, the
normal course of migration in the case of Eichard's Pipit is from
north to south or thereabouts. Why certain meteorological
conditions should effect such small numbers of the former
species in comparison with the latter is incomprehensible. To
the writer the prevalence of south-easterly winds at the time of
migration does not afford at all an adequate explanation of the
fact that only a limited number of individuals should be induced
33
thereby to forsake their normal course, when the great body of
their fellows remain unaffected.
With regard to migrations of Kichard's Pipit being conducted
in a broad front corresponding in width to the latitudinal area of
the breeding-range, no more telling facts against such a theory
than those related by Herr Gatke could well be adduced.
Remarking on the numbers of the species occurring in Heligo-
land, he writes (p. 118) : " Again, if twenty, fifty, or even a
hundred examples of Eichard's Pipit occur here in one day,
these numbers can only represent a minute fraction of the
quite incomputable quantity of these birds which are travel-
ling at the same period from Dauria to Western Europe."
Whatever the probabilities are of the Yellow-browed Warbler
or other species being overlooked in their European winter
quarters, it is quite impossible that a much larger species
with a loud clear call-note and in " incomputable quantities "
could escape observation in like manner. For, apart from its
much greater size, the present species frequents the open
country and not bushes and thickets like the former, as Herr
Gatke points out. It is more, perhaps, on account of these habits
and general conspicuousness, that Richard's Pipit has been so
frequently observed in Western Europe than by reason of its
occurrence in any supposed vastly greater abundance than the
Yellow-browed Warbler. No doubt it does actually occur in
larger numbers than the latter, though not to anything like the
extent Herr Gatke' s theories require. One also wonders what
becomes of these supposed vast flocks, or in what particular
country they find winter quarters. Perhaps, like several other
species, they are assumed to pass over those districts where they
are unknown, at a great elevation, though even under these cir-
cumstances, they might reasonably be expected to be observed
on the theory of a rigidly performed east-to-west flight.
It will be interesting to compare Herr Gatke's notes on the
migration of Richard's Pipit, published in another place, with
the foregoing. Since the appearance of the first edition of his
work writing in the Zoologist, 1893, p. 164, in reply to a
communication from the late Henry Seebohm he remarks :
" Widely different stands the case with Anthus Richardi, a
3
34
native of the far east of Asia, from Lake Baikal to the Sea of
Ochotsk ; its regular line of autumnal migration runs south, and
it consequently is a common winter resident in South China and
the eastern parts of India Bengal, for instance being in
Calcutta a plentiful market bird during the winter months.
Such individuals, therefore, as under exceptional and undoubtedly
meteorological influences adopt at irregular periods, though in rare
instances in comparatively considerable numbers, a western instead
of their normal southern autumnal migration flight, can reasonably
be pronounced only accidental visitors to Europe. The more so
since even the cases of appearance in greater numbers of this Pipit
have occurred mostly at intervals of from six to ten years, viz., in
1839, 1848, 1849, 1859, 1868, 1869, 1870, 1876. On account of
prevailing westerly ivinds A. Bichardi has during the last fifteen
years been obtained here but once or twice about every third year."
The above passage is directly at variance with the statement
on p. 29-30 to the effect that " Nor must such individuals be
in any sense regarded as isolated rarities or ' stragglers,' for
not only are they met with regularly every autumn, but they
frequently attain to the comparatively large numbers of from ten
to fifty, and in two or three instances of even a hundred in-
dividuals in a single day." After the above admission that A.
Bichardi should only be treated as an accidental visitor to Europe,
we shall undoubtedly be justified in placing a very small value
on the evidence its occurrence affords, of a general migration from
the far east of Asia to the west of Europe ; and as this is by far
the most numerous of the Asiatic visitors to Heligoland we may
fairly treat the casual visits of those species, only occurring once
or twice during a period of fifty years, as still more accidental.
What the many other species are from far eastern Asia which,
to use Herr Gatke's own words " visit Heligoland in such
large numbers every autumn " (p. 33), one is at a loss to know.
A few words must be written on the autumnal migrations of
the Goldcrest, for from a cursory examination of Herr Gatke's
remarks on this species, they might appear to confirm the theory
that the flight sets out from the breeding grounds in Norway in
the manner he describes. There can be no doubt that the large
numbers or rushes of this species which have at times arrived on
35
our eastern coasts are derived from the former country, as at
these particular periods there has been either no corresponding
rush over Heligoland, or the species has occurred there in smaller
numbers than usual. Indeed it will be gathered from a remark
of Herr Gatke's on p. 15, that mass migrations of this species
rarely pass the island.
To enable these large flights to collect together, a certain
amount of concentration on to particular stretches of the
Scandinavian coast-line must of necessity take place. It cannot
be imagined that all the individuals in a particular district, which
might have an area of many square miles, set out from their
nesting stations at an identical moment. Probably the first
move is down some broad and well-timbered river valley to the
sea. On arriving at the latter, the various flights are banded
together whilst waiting the advent of the anti-cyclonic conditions
so necessary during the migrations of so feeble a species.
On these conditions becoming prevalent the majority will
probably take early advantage of the opportunity to at once
undertake their flight over the North Sea. In crossing the latter,
however, there can hardly fail to be a considerable amount of
spreading amongst the flocks. From this fact, and also from the
probability that there are many starting points, the flights on
reaching our islands will affect a considerable length of coast line.
Moreover, all do not proceed directly inland ; many will continue
the journey by following the latter to the south, and as these
rushes occasionally extend over a period of several days, flocks
which have really arrived in the north, and have since travelled
many miles further, may come to be regarded, in other localities
1 through which they may pass, as new arrivals from over the sea.
I Thus so far from having conducted the migration in a broad front
| corresponding to the latitudinal area of the breeding grounds,
the flight has been really performed in several narrow columns,
which have become partially dispersed in crossing a wide sea.
Herr Gatke in later chapters of his work alludes to large
flights of Plovers, Curlews, Godwits, Sandpipers, Oyster-catchers
and other species occurring late in the year, at times quite beyond
the ordinary migration period of these species. These supplemen-
tary migrations are usually accompanied by the advent of severe
36
weather. In the manner of their performance, however, they
do not differ from the flights at the normal periods of the year.
These individuals, moreover, have long since left their nesting
stations, and there can be nothing suggestive of a broad front
corresponding in breadth* to the latter, in the manner in which
these late birds pass the island. Why, therefore, should Herr
Gatke conclude that the latter mode of flight is characteristic
of the migrations of the same species which take place in the
ordinary course, but which do not visibly differ in the manner in
which they are conducted from those under notice.
As further evidence of, and in confirmation of his theory of an
east-to-west autumnal flight, Herr Gatke frequently refers to
the observations of a well-known ornithologist, viz., Mr. John
Cordeaux, a gentleman living near the Lincolnshire coast in a
locality almost due west of Heligoland, and whose opinions he,
in common with all naturalists, holds in high respect. As an
example, on p. 26 he writes : " Mr. John Cordeaux ....
informs me that the bands of migrating Hooded Crows do not
alight immediately upon reaching the coast, but continue their
journey inland in a westerly direction," and other notes to the
same effect. That the latter gentleman, however, does not
intend his remarks to apply to all immigrants arriving on our
east coast may be readily shown from his writings in other
places. Eeferring to two great rushes of birds in 1892, com-
prising Eedstarts, Whitethroats, Eobins, Pied and Spotted
Fly-catchers, Wheatears, Hedge Sparrows, Goldcrests, Grey
Shrikes, Larks, Eing Ousels, Blackbirds, Eedwings, Thrushes,
Willow Wrens, and a few others, he remarks : " In both
these cases of great rushes, which I have cited under similar
meteorological conditions, great flights of immigrants were evi-
dently passing the North Sea, probably from north-east to south-
west, when the easterly gales caught them on the flank and drove
them helter skelter on to the east coast " (Zool., 1892, p. 420).
And again in the same journal (p. 227, 1893) he expresses the
opinion that the migratory Eock Pipits which visit the east coast
in the autumn are almost exclusively the Scandinavian form from
the north-east.
Still more to the point are further remarks bearing on the ques-
37
tion of an east-to-west flight, which appeared in The Naturalist,
1894 (p. 420). He writes: "As a rule the small summer
visitants to northern and central Europe, such of them as reach
the coast of Great Britain in the autumn passage, do not pass
inland or cross the country, but follow the coast line south. This
is the case with the Eing Ousel, Wheatear, Eedstart, Willow
Wren, Pied Flycatcher, Yellow Wagtail, and a great many other
small species far too numerous to mention, and so much is this the
rule that an observer residing a few miles inland will be ignorant
of the immense movement going forward within so short a
distance." The latter remark also throws some light on the
question of migration in a broad front.
The above extracts will be sufficient evidence to prove that
Mr. Cordeaux fully recognises a strong migratory movement
travelling between the points of north and north-east to south
and south-west, and that the opinions expressed in his writings
referred to by Herr Gatke are only to be applied in a limited
sense.
Further references to the opinions expressed by the same
gentlemen, that many of the migrants arriving in north Lincoln-
shire from over the sea reach the latter locality from a due
easterly direction, though somewhat contradictory to those
previously quoted, may possibly be explained in the following
manner. Birds crossing the North Sea from north-east to south-
west, on first catching sight of the land when out at sea, will very
probably so alter the course of their flight in order to reach it as
early as possible, as to give an observer the impression that they
I fibre coming in directly from the east.
Mr. W. Eagle Clarke, however, on whose shoulders has fallen
the labour of digesting the immense amount of material fur-
nished by the observations of light-house keepers and others
at the instance of the Committee appointed by the British Asso-
. ciation to study the question of migration has expressed himself
very decisively on the supposed identity of the migration over
Heligoland with that affecting our east coasts by a direct east-to-
west flight. On p. 7 of his digest he remarks : " Much prominence
i has been given in some of the Annual Keports issued by the
Committee, and in Herr Gatke's book, 'Die Volgelwarte Helgo-
38
land,' to an inter-migration between Heligoland and the east
coast of England by a direct east-to-west autumn, and, it is to
be presumed, west-to-east spring, movement. Herr Gatke most
obligingly communicated details of tbe bird movements observed
on Heligoland for four years (1883-1886), during which the in-
quiry was being prosecuted over the British area. These two
sets of data have been carefully examined and compared, and it
has been found that the dates of the chief movements of the
species common to Heligoland and eastern Britain seldom, if
ever, correspond, and do not bear out this theory ; that particular
species which are irregular as migrants in Britain, such as the
Ortolan Bunting, and others, occur regularly, often indeed in
' rushes ' at the more favoured isle off the mouth of the Elbe ; that
other species which are very rare on our British shores occur in
Heligoland as regular migrants and in considerable numbers, as
Motacilla flava, Anthus Eichardi, &c., while species common to
both islands occurs in 'flights like clouds,' in 'hundreds of
thousands, * thousands upon thousands,' in ' marvellous numbers,'
' astonishing flights,' and so on, at Heligoland, at periods when
there is not a single observation for the same species on the
English shores. A study of the phenomena of migration com-
pels the investigator to come to the conclusion that Heligoland
and Britain draw their migratory hosts from different sources."
Mr. J. H. Gurney has been at some considerable pains in
drawing up a comparative list of the occurrences of certain species
which have arrived at various times on Heligoland and on our
east coasts in exceptional numbers, and whilst the result might
appear to some extent to confirm the view that a close connection
exists between the migratory streams affecting both localities, still
he does not fail to point out that in the greater number of in-
stances there is no connection whatever. Mr. W. Eagle Clarke
further expresses the opinion that as " the ordinary movements
of any common migratory bird occur in each month of its
seasonal flight-periods, and the mere coincidence of the species
being observed simultaneously in ordinary numbers on both sides
of the North Sea, has no significance whatever. It is not im-
possible or improbable that birds may occasionally cross the
German Ocean by an east-to-west flight in the latitude o\
I 39
Heligoland, but our data lead us to believe that such cases are
the rare exception, not the rule." According to the same gentle-
man, the records kept at the Outer Dowsing Lightship, the most
isolated of the stations in the North Sea, situated thirty-eight miles
E.S.E. off the mouth of the Humber, or almost in the exact lati-
tude of Heligoland, strikingly confirm this opinion.
It is difficult to see on what grounds Herr Gatke has based
his theory that the general course of migration trends from east to
west. Apart from his own observations conducted on Heligoland
he brings forward very little confirmatory evidence. He, how-
ever, in one place refers to a statement of the late John Wolley's
as furnishing the most northern illustration of an autumn migra-
tion proceeding in this direction. It appears that the latter
observer, after only a year's residence at Muonioniska, in lat. 68
N., came to this conclusion on account of the large numbers of
the Yellow Bunting he met with at the close of summer. These,
in his opinion, could only have come from a district lying to the
east. Mr. Seebohm, however, considered this species rather rare
in the Petchora district ; whilst Collett states that even in the
extreme north of Norway a few individuals remain throughout the
winter ("Bird Life in Arctic Norway"). If follows, therefore,
that the present species is an abundant summer migrant in the
latter locality. Herr Gatke, however, even in this instance, is
constrained to admit that the further course of migration on the
part of this Bunting must be to the south, otherwise it should
visit the Shetlands in large numbers, whilst the reverse is actually
the case. Compared with the distance travelled in the latter
direction any westward flight, which, moreover, would be hardly
likely to comence further east than the shores of the Kola Penin-
sula, is very trivial.
Herr Gatke also calls attention to the presence of countless
droves of land birds, both of the larger and smaller species, as
well as of Ducks, Geese, Swans, and other water birds, which
may be seen in the aatumn months on the coasts and interior
parts of the west of Scotland. All these, he states, are hasten-
ing to their winter quarters in a southerly or south-south-easterly
course. This may be true of the land birds, not only at that par-
ticular time and locality, but may equally well refer to the whole
40
journey. It is difficult to see what evidence there is to show,
however, that these droves consist in part of birds which, like
the Brambling, after arriving on the east coast, have traversed
the latter country in a westerly direction. The flight of these
flocks, according to the evidence afforded by the observations of
light-keepers and others, either stih 1 maintains its south-westerly
course, or follows the eastern coast line into England.
With regard to the Brambling. The movements of this
species from Northern Scandinavia are said to first conduct them
to the southern parts of Sweden. Possibly this is correct, but
that they then turn directly west is very doubtful. It will be
evident if they merely follow the general trend of the land their
course must necessarily be to the south-west, and if again they
leave the coast of Norway at its most westerly extension, this
same direction of flight need merely be still maintained to
eventually land the travellers on the mainland of Scotland, and
not on the Orkneys and Shetlands.
Herr Gatke, however, has quite overlooked the presence of
many migratory species in the Faroe Isles, and still far greater
numbers in Iceland. It is absurd to suppose that birds from
either of these localities migrate in autumn to the west. It
therefore naturally follows that the hordes of water-fowl and
shore-birds observed on the west of Scotland must in great
measure be derived from these northern islands, and not from
districts in the north-east of Europe, as he supposes. When,
however (p. 31), he is driven, in support of his theory of an east-
to-west line of flight, to allude to the fact of the Gannet having
been observed passing in a westward direction for six or eight
days together at Cape Wrath, its weakness will be apparent ;
for it is well known that no breeding places of this species exist
to the east of Scotland, the movements in question being merely
due to wanderings in search of food.
It is on evidence of this nature, and in conjunction with his
own Heligoland notes, which have already been discussed, that
be bases the assertion that "the flight of these migrants has
thus been followed from Eastern Asia to the Atlantic shores of
Europe. In the case of the most different species, and in dis-
tricts so widely separated as Central Germany, Heligoland, the
41
eastern coast of Great Britain including the Orkney and Shet-
land Islands Norway up to a latitude of 70 N. in Finmark,
the same results as to the direction of the migratory flight have
been obtained."
Why certain species should follow such a course, and the
remainder should fly from north to south, he offers not a word in
explanation, and he quite ignores the results of inquiries con-
ducted by ornithologists like the late Dr. Severzoff, as regards
Central Asia ; and Dr. Menzbier as regards Eastern Europe ; or,
again, by Von Middendorff, who, after selecting seven typical
species, found that in the middle of Siberia the general direction
of the usual migrants is almost due north, in the east of Siberia
from south-east to north-west, and in European Russia from
south-west to north-east. Prof. Palmen's conclusions are similar.
Whether we accept the theories of the latter as to the manner
in which birds are guided, or not, is of little importance at the
present juncture, and does not affect the accuracy of his state-
ments on the direction of the migratory flight.
It is no doubt true, as pointed out by Dr. Menzbier, that there
are no such things as fly-lines. Probably every species goes its
own way, and what is called a migration route is only the co-
incidence of the way taken by many (Newton, "Dictionary of
Birds "). How Herr Gatke, however, can formulate a theory of a
migration carried out in a broad front, corresponding to the lati-
tudinal area of the breeding-ground, and rigidly conducted in an
east-to-west direction, in the face of the heterogeneous assem-
blage of individuals and species which pass with such regularity
and in such wonderful proportions at his little island, is im-
possible to imagine. With regard to the confirmatory evidence
of a general migration in an east-to-west direction, afforded by
the capture of a few Siberian species during a period of more
than fifty years, as well might it be argued, from the occurrence
of over 250 American birds in Great Britain in the same lapse
of time, that the general tendency of migration in the latter
continent is in the reverse direction.
In objecting to the theory that birds follow coast lines as
guides during their migration, Herr Gatke, referring to Eichard's
Pipit, and others, inquires " Are we, therefore, to assume that
42
when arrived at the Baltic they suddenly become incapable of
continuing their journey except by following the comparatively
small span of coast to Holstein?" To this one might fairly
retort Are we to assume that, because birds in passing Heligo-
land are either seen or heard to be travelling in an east-to-west
direction, that this is the course of flight maintained throughout
the whole duration of their journey ?
We turn now to the consideration of Herr Gatke's remarks
on those species which he tells us travel to and from their breed-
ing-grounds in a direct north-to-south, or the reverse, line of
flight. There will not be the difficulty in accepting his conclu-
sions as to the general direction of this flight as in the previous
case, but exception must be taken to the assertion that it is per-
formed in the rigid and undeviating manner as described; and
also to the theory that it is conducted in a broad front, in a
similar mode to the east-to-west flight.
In considering Herr Gatke's arguments, his admission that
not a single bird is seen to arrive at or depart from the island in
either a north or south direction must not be forgotten. Yet
he tells us that this north- to-south line of flight is " peculiar to
a large number of species, more especially such as have their
breeding-quarters in high northern latitudes, and, in respect to
the individuals taking part in it, fully equals the great east-to-
west migration, while, as regards the distance traversed, it in
many cases even surpasses the latter movement." We are,
therefore, driven to the conclusion that it is the consideration
of the breeding-ranges of the species which are said to comprise
this movement rather than the result of actual observations on
which he bases his theory. One is rather puzzled to know what
species are comprised in this flight, as, on pp. 25 and 30, several
having their breeding-grounds in the high north are included in
the list of those said to be derived from the far east ; others such
as " the Bluethroat, Wagtails and Warblers we are told
appear on and depart from the island in a manner precluding
the possibility of our being able to realise by our senses the
direction of either their arrival or departure."
Amongst the species specially singled out in illustration of
this north-to-south flight is a very well-known one, viz., the
I 43
Red-spotted Bluethroat. Referring to its geographical distribu-
tion Herr Gatke writes : " This species breeds in high northern
latitudes of the old world from Kamschatka as far as the
central and northern portions of Norway, while its winter
quarters range throughout the whole of Southern Asia and over
the eastern half of North Africa." It may here be pointed out
that most authorities refer to Egypt as the winter quarters of
the Northern Bluethroat, as Herr Gatke himself does in other
places. This point is of importance in view of the fact that
Herr Gatke makes such special reference to the undeviating
character of the flight. As the latter part of North-eastern Africa
is the only locality where this species is found in winter, it is
difficult to see how a rigidly performed south-to-north flight
would cross Heligoland at all. He further adds: "In Heligo-
land, as well as in Germany and Italy, it is of quite regular
autumnal occurrence ; in England, on the other hand, only
solitary examples of the bird have ever been met with, and
these only at intervals of many years . . . ." With regard to
the latter remark, Herr Gatke's information is certainly not up
to date, for he quite overlooks the occurrence of the species in
North Norfolk where over a hundred were observed at one time.
In the opinion of Professor Newton, the Bluethroat probably
occurs on our east coast with regularity, but is, no doubt, over-
looked (" Dictionary of Birds ") . Reference also to Mr. Cordeaux's
notes in the Naturalist will prove that hardly an autumn passes
without one or two being observed in the Humber District ; other
occurrences are alluded to in the reports issued by the committee
on the migration of birds. It has also been recorded from
Malaga and Valencia in Spain (Irby). One cannot help specu-
lating whether, if Herr Gatke had not overlooked these facts,
he would not have been tempted to include the Bluethroat
amongst the species migrating by the east-to-west route, for its
distribution is very similar to that of several species comprised in
the latter. His following remarks will afford good evidence,
after noting the above omissions, of the danger of attributing
a rigidly-maintained direction of flight to any species whatever.
He writes : " It hence follows most decisively that the bird,
in autumn, rigidly adheres to a southerly course of migration
44
and travels in a broad migration front which corresponds to
the longitudinal range of its nesting area, and of which Heligo-
land forms the most western limit. Even a slight westerly
deviation from their southerly course of such species (indivi-
duals ?) as breed in the west of Norway could not fail to convey
large numbers of these birds to the east coast of England,
and their all but total absence there furnishes, therefore, an
undoubted proof of the persistence with which the southerly
course of migration in this instance is adhered to." It has
already been pointed out that the Bluethroat is not of so
casual an occurrence in England as Herr Gatke supposes, and
if we bear in mind that the winter quarters of this species in
North-eastern Africa are limited almost to Egypt, it becomes
evident that the individuals breeding in the westernmost parts
of their range would, on their return journey, if they took a
direct route, fly from north-west to south-east. The pretty
regular appearance of examples in England is, therefore, still
more worthy of note. One would naturally expect the species
to occur fairly numerously in central Europe on the return
journey, owing to the proportion of young birds which would
then be travelling, and also on account of the more leisurely
manner in which the latter flight is conducted. But, judging
from the evidence placed before us, it appears to be rather local,
even in this large area.
The difficulty of accepting the theory of a migration conducted
in a broad front is perhaps more apparent in the case of the
Northern Bluethroat than in any other species to which Herr
Gatke refers. Writing on the spring flight he remarks (p. 265) :
" In the absence of cold and dry northerly winds at the end of
May and April, it appears here [i.e., Heligoland] , as a daily visitor,
and if, in addition, the weather be warm and fine, with a light
south-east wind, it frequently occurs in such large numbers that
on days of this kind Oelrich Aeuckens and myself have succeeded
in obtaining as many as from thirty to fifty male individuals."
He also tells us (p. 44) that on May 26th, 1880, the species
occurred on the island in thousands. In certain preceding
passages Herr Gatke lays special emphasis on the fact that the
Northern Bluethroat has only been obtained during its spring
45
flight, in very exceptional instances, in Italy, the north of
Germany, and in other localities south of the latitude of Heligo-
land. This he regards as strong evidence of the unbroken
character of the flight. But may not these facts be quite as
reasonably cited in evidence of the narrowness of the migrating
column ? The paucity of observers in south Europe, too, must
not be overlooked. Herr Gatke seems to be quite certain in his
own mind that the Bluethroats passing his observatory in spring
are identical with those which breed in western Norway. To
the writer, however, the evidence is all against the accuracy of
this assumption. In the first place we are confronted with the
remarkable fact if such were the case, and if the assertion is
correct that these Norwegian individuals occupy the extreme
westerly extent of the advancing column that it is only the
latter individuals that take a rest during their flight, though they
have the shortest distance to travel. This is a curious circum-
stance in view of the statement that the Bluethroat migrates
at the rate of 180 miles an hour, and also that by the time
it reaches Heligoland it is rapidly nearing its destination in
western Norway. Furthermore, this rest appears to be taken ai>
times when the meteorological conditions are most favourable to
the performance of an unbroken flight, i.e., during the prevalence
of light south-easterly winds with warm weather. If the species
migrates in a broad front, how do those individuals dispense with
a rest who must, of necessity, travel over the whole length of the
Baltic and Gulf of Bothnia, if they rigidly confine their flight
between the points of south and north ? One cannot help here
remarking on the inconsistency of Herr Gatke's arguments. In
the case of the Shore Lark and Hooded Grow, we are told the
vast hosts which pass Heligoland can only be derived from a
country extending from the Atlantic to the Pacific, but in the
present instance, a species, which has always been looked upon as
only moderately common, occurs in thousands on one day alone,
viz., May 26th, 1880, and, moreover, on a tiny island. In the
face of these facts we are asked to believe that these large
numbers are journeying north to breed in a very limited area in
the most southern and western extension of the breeding range.
Does not the above evidence point in a far stronger manner to
46
the fact that the Northern Bluethroat migrates at any rate in
spring in a very narrow column or columns, and bearing but
little relation to the extent of the winter quarters and breeding
range ? Shall we not also be much safer in assuming that the
large numbers occasionally noted on the island late in May are
individuals breeding in the far north ? We should expect those
whose nesting homes lie in the most southerly portions of the
breeding range to have already commenced operations by May
26th. Even in the Petchora valley, Messrs. Seebohm and Harvie
Brown note that the Bluethroat arrived in this northern locality
quite a week earlier. Again, the winter quarters of the Blue-
throat in north-eastern Africa are very much more confined in lati-
tudinal extent than are the breeding grounds in northern Europe,
so that there must be considerable spreading of the flocks, and,
consequently, no rigidly adhered to, south-to-north direction of
flight during the spring migration, if conducted either in many
narrow, or in one broad column. To the writer there seems to
be little doubt that the Bluethroats calling at Heligoland during
May form a succession of flocks travelling in a narrow flight over
a customary route to breeding grounds in the north of Scandinavia
and Lapland, and that their non-appearance in certain years is
due to a deflection of the stream which may readily miss so tiny
an area as the island, or even break the journey at other points.
The fact of individuals so rarely occurring in intermediate
localities, though surprising in itself, is much less difficult of
comprehension on this theory. Herr Gatke himself perhaps
gives a clue to this mystery in his charming opening words,
referring to the progress of migrants, where he speaks of our
" sharing in their joy when some high mountain valley offers a
portion some temporary rest and refreshment " (p. 3).
But the paucity of observers in southern Europe must by no
means be overlooked in accounting for the absence of spring
visits of this species.
As before noted, Herr Gatke does not devote much space to
the consideration of the autumnal flight of migrants which pass
from north to south. In addition to the Bluethroat, however, he
refers to a few other birds. Amongst the latter is the Eed-
throated Pipit, a species breeding abundantly above the Arctic
47
circle from Norway eastwards; but whose winter quarters lie
to the south-east, rather than the true south, of Heligoland.
Colonel Irby, however, met with two examples at Gibraltar, and
expresses the opinion that it passes that point regularly on
migration.
Referring to the geographical distribution of this bird,
Saunders writes (Manual of British Birds) : " It breeds in
many parts of Scandinavia, especially in East Finmark ; while
eastward we find it in increasing numbers, beyond the limits of
forest growth, across Siberia to Kamtschatka and Bering Island.
It is even said to have straggled across the Pacific to Lower
California ; but, be this as it may, the migrations of this Pipit
undoubtedly extend to southern China, Borneo, Burma, India,
Persia and Egypt. In the latter and in Nubia the bird is
exceedingly abundant in winter ; westward in North Africa it
becomes rarer ; but it is found on migration throughout the basin
of the Mediterranean from Asia Minor to Gibraltar."
This Pipit from its similarity to A. prateusis is very likely to be
overlooked. This view is strengthened by Herr Gatke's further
remarks. With regard to its occurrence on Heligoland, he
writes : " I obtained the first example of this Pipit on the
island on 28th September, 1854, and the second on 20th
September, 1857. Soon after, Glaus Aeuckens learned its call-
note, and in consequence managed to see and frequently shoot
one or other of these birds regularly every autumn. In 1884
they occurred here in unexampled frequency ; from 15th to 30th
September thirteen examples were seen, and for the most part
shot, on some days as many as three examples " (p. 345).
The above account, however, will be found to be quite at
variance with a reference to this species on p. 37. In the
latter place the author writes of the Eed-throated Pipit as
only occurring in Heligoland in the most exceptional cases,
having only been shot there more than six times within the
last fifty years. The latter fact having been brought forward as
evidence of the extreme rigidity with which the north-to-south
line of flight is adhered to, its value will be apparent when com-
pared with the previous statements. The admission, too, that as
soon as one of Herr Gatke's best assistants became acquainted
48
with the call-note, the species should be noted- afterwards as
of regular occurrence, is significant, and points to the fact of its
having been previously overlooked. The same has probably been
the case on our east coasts. So experienced an observer as Mr.
Cordeaux has expressed the opinion that it would be almost
impossible to detect the Bed-throated Pipit amongst a flock of
Meadow Pipits even with the aid of a good field glass. Further-
more, in various parts of the text the author includes A. Cervinus
amongst those species which are brought forward in evidence of
an east-to-west line of flight (p. 116). It is odd to read, there-
fore, that it "likewise adheres to a most rigid southerly course "
in its autumn migrations.
In considering the migrations of this species Collett remarks :
" Like most of the genuine migrants of the order Passeres,
the small birds do not reach their northern nesting-places across
the southern parts of Norway, but by the eastern route across
Eussia and the Baltic provinces. One consequence of this is
that the Eed-throated Pipit and Siberian Willow Warbler are
either not met with at all during migration in the southern
parts of the country, or appear there only occasionally and
accidentally " ("Bird Life in Arctic Norway").
Turning now to two other species singled out by the author,
viz., Eversmann's Warbler (Sylvia borealis) and the Northern
Nightingale (Sylvia philomcla) we find that the former of these is
stated *' to direct its migration flight in an equally unswerving
southerly line." Unfortunately but little of the winter distribu-
tion of this tiny species is known, but it seems to be identical
with that of the Eed-throated Pipit and several other species
breeding in Northern Europe, lying rather to the south-east than
the true south of the western limit of the breeding range. In
whatever manner the migration is conducted it will trend in the
former direction, and the chances of the species turning up in
Heligoland are thereby much reduced. Writing on this species,
Collett remarks : " In Finmarken it is a recent immigrant, and
its migrations therefore do not pass southwards along the Baltic
provinces, like that of our other Arctic small birds, but it migrates
across the large river basins of Siberia, in order to reach down tc
the Pacific Coast, China and India, where its chief winter home
is" (" Bird Life in Arctic Norway," p. 30).
49
The absence of records from neighbouring countries points
rather to the fact that the flight is conducted in pretty compact
flocks and not in a broad front. If the latter were the case, more
straggling might reasonably be expected. In this instance,
apparently, the author does not apply the rule that the species
should occur in numbers proportionately greater in Central
Europe as the size of the latter area is to that of Heligoland,
though to be consistent he should do so. He does not even
suggest that Eversmann's Warbler has been overlooked in other
parts. This is a fair example of the varying treatment identical
evidence, in support of divergent theories, receives at his hands.
The very casual appearance in Heligoland of the Northern
Nightingale is not difficult to account for ; the breeding range of
this species extends but little further north than the latitude of
the island. On leaving their nesting stations in the autumn,
migratory individuals are far more likely to deviate from their
normal course in the middle or latter part of their journey than
at its commencement. It must not be forgotten, too, that as the
limits of the breeding grounds are approached birds become much
scarcer than in the central portions. In the present case an
early westward deviation of Swedish individuals would be far
more likely to be observed on the coasts of Denmark, where such
stragglers would probably unite with local examples of their own
species. It may be further remarked that the single record of the
Northern Nightingale in Heligoland was noted on the night of
May 4-5 at the lighthouse lantern. It seems quite possible that
this was an individual which had overshot its breeding grounds
in the Rhine Valley, where, according to Seebohm, the species
occasionally nests.
The remaining species alluded to by Herr Gatke as conducting
their migrations strictly between the points of north and south,
viz., Siberian Chiff-Chaff, Yellow-headed Wagtail, Yellow-breasted
Bunting, Terek Sandpiper, and Eed-footed Falcon, are all birds
having their winter quarters for the most part in the south-
eastern portions of the Palaearctic or oriental regions ; and their
breeding ranges extend but rarely any distance further westward
than long. 25 E. It would therefore require a very considerable
deviation from a direct southerly flight to carry individuals over
50
Heligoland. Still for all that, such a contingency occasionally
happens in the autumn months. In such instances the explana-
tion, to the writer, seems to be that these stragglers have
accidentally attached themselves to flocks of other species whose
ordinary flight passes the island.
In the case of the Yellow-headed Wagtail, it may be remarked
that up to the present this species has not been found breeding
west of the valley of the Petchora. That it should have occurred
on migration no less than five times in so distant a locality as
Heligoland is remarkable, and forms additional proof that many
of the migrants which according to Gatke, are derived from the
east really come from northern and north-eastern regions.
The above remarks also apply to the Siberian Chiff- Chaff and
Yellow-breasted Bunting ; though their breeding ranges extend
further west. The latter species, it may be noted, has occa-
sionally been found in Southern Europe.
As an exception to the rule of a migration rigidly performed
between the points of north and south, or rather in accounting
for the regular appearance on Heligoland and in other parts west
of the ordinary limits of such a flight, Herr Gatke makes especial
reference to the Little Bunting. On page 34 this species is said
to migrate in a direct north-to-south line of flight, but later on in
bis work the author includes it amongst those which are supposed
to migrate westward from Eastern Asia. On page 34 he remarks :
" More or less considerable numbers of individuals turn to the
west on quitting their nesting stations, and migrate to Western
Europe instead of Southern Asia." He further adds : " This
tendency is by no means peculiar to those species whose breeding
range extends to Western Asia or North-eastern Europe, as is
proved by the cases of the Siberian Chiff- Chaff, the Yellow-
breasted Bunting, and the Terek Sandpiper. On the contrary,
all our experience goes to show that it is more especially mani-
fested by species whose breeding homes are furthest removed
from Europe. . . . Moreover this tendency is generally confined
to particular species only of a genus, being entirely absent in
others of the same genus. In proof thereof we may cite the case
of the Yellow -breasted Bunting and the Little Bunting two
species breeding in the north-east of European Russia, whose
51
nests may be found almost side by side. Of these the former
has only been seen in Heligoland on three occasions within more
than fifty years, and with the exception of an example met with
at Genoa, has never been observed in Central or Western Europe.
The Little Bunting, on the other hand, appears in Heligoland
every autumn, and is frequently shot. ... In the south of
France it is said to be the commonest of the rarer Buntings,
small companies of it wintering at Marseilles. [He might also
have added that nine examples were obtained near Malaga, in
Spain, December 28, 1874 (Irby)]. Inasmuch, then, as both
species are found breeding in about equal numbers in the neigh-
bourhood of Archangel, both, too, belonging to the group whose
autumn migration is directed south, we are confronted by the
question as to what may possibly be the cause which determines
the one the Little Bunting annually in large numbers to turn
west on starting from the common nesting home, while the other
the Yellow-breasted Bunting is hardly ever induced to swerve
in this manner from its normal southerly course."
After reading the above and comparing it with further re-
marks on the Little Bunting in other parts of the book, one is
somewhat puzzled as to whether Herr Gatke intends we should
gather that the Little Buntings met with on Heligoland are sup-
posed to be derived from the neighbourhood of Archangel, or from
far eastern breeding grounds in Asia. If from the latter locality,
then, according to the author's treatment of other species, their
flight would come under the category of an east-to-west descrip-
tion, and not, as previously stated, of a north-to-south type. A
reference to the records of the Little Bunting on Heligoland
seems to point to the fact that the individuals touching there are
derived from two districts, as there is a break in the continuancy
of migration, not a regular dribble of individuals during the
autumn as with other species. As the species breeds throughout
Northern Russia, east of the White Sea, it may perhaps be the
case that the later arrivals come from the Petchora, or other river
valley in the north-east. In any case there is no evidence of a
flight rigidly performed either from east to west or north to
south, though the general direction appears to be from north-
east to south-west, or thereabouts.
52
Herr Gatke seems to think that the appearance of certain
species on Heligoland, whose breeding grounds for the most part
lie in Asia, is due either to an innate tendency to wander, or to a
deliberate turn to the west on setting out on their migrations.
In other places, however, it must not be forgotten that he
attributes this westward wandering to meteorological influences
prevailing at the period of autumnal migration. If the former
supposition is correct, it is difficult to see how this tendency has
been inherited without producing a more general effect on the
particular species which are said to be subject to its influences.
It is significant that those which are supposed to be so affected
have, as Herr Gatke admits, for the most part only been detected
on the island in single instances ; but as the Yellow-breasted
Bunting and Yellow-headed Wagtail have occurred more fre-
quently, it is remarkable that he has not brought them forward
too in illustration of this tendency rather than treating them as
species, which prove how rarely a certain other group of birds
deviate from a rigidly performed north-to-south flight. The
probability of the fact, that because certain species have occurred
on Heligoland in small numbers, therefore they should in like
manner occur in much larger numbers in Central Europe, seems
to the writer to depend entirely on our acceptance of the theory
that birds migrate in a broad front. Whether this is so or not, '
it seems very unlikely, however, that the small number which
are apparently induced to travel westward should adopt such a
form of migration.
With regard to the progress of the spring migration from south
to north, Herr Gatke's remarks are very interesting, and form
a striking example of how the habits of birds differ in various-
localities. On page 41 he writes: "Here we nowhere meet
with any attempts at dividing the long migration flight into short
convenient stages such as is often the case after the first great
advance during the autunm migration ; nor do the birds at this
time anywhere exhibit a tendency for taking long spells of rest
in the course of their journey. Unrest and an impelling haste
are everywhere the prominent characters of the movement dur-
ing its whole progress." Observations conducted on Heligoland
no doubt bear out this statement, and we can hardly imagine
53
birds lingering at such an uninviting spot especially uninviting
in the spring unless their need for food or rest were very urgent.
But in other localities the observations of naturalists point to
quite a different conclusion. In our own country, for instance,
at various points on the east coast, certain species make their
appearance with great regularity at particular times, and so far
from evincing any of this unrest and impelling haste, are content
to linger for days together before further continuing their
journeys.
The Fieldfare may be singled out as a species illustrating this
fact ; even those flocks which pass through the Midlands at so late
a period in the spring as the first week in May, so far from
exhibiting any of this restless haste, may be seen lingering in the
same fields for several days at a time, instead of at once passing
on. The case of the Dotterel a species breeding in the far north
of the Palaearctic region too, is similar, flocks of which are known
to tarry in certain districts, not for days, but for whole weeks
together. Again, at Gibraltar, Col. Irby as early as March llth
met with very large numbers of the Common Crane migrating due
north. In the course of a single hour he calculates that at least
four thousand must have passed by. As the Crane breeds only
very locally and very sparingly in Spain, there can be no doubt
that these flocks were en route to the north of Europe. But at
this period their breeding grounds would not be fit for habitation.
No doubt the journey would therefore be broken at some convenient
locality in Western Europe. To the writer the very fact of so vast
a number of birds visiting a little spot like the island which Herr
Gatke describes as a most unattractive residence for birds, points
to the probability that the greater number certainly of the smaller
birds, if not the larger also conduct their migrations in compara-
tively short stages. The fact of the greatest number calling during
periods which we are told are the most favourable to an unbroken
flight viz., the prevalence of warm weather with light south-
east winds seems to lend additional force to this conclusion.
The central position alone of Heligoland does not afford satis-
factory proof that this is the true reason why the island is so
exceptionally favoured as a place of call by so many species.
For, on Herr Gatke' s theory of migration, conducted in a broad
54
front, the neighbouring islands should be equally patronised.
Indeed, the position of Heligoland can hardly be called central,
except in relation to Western Europe, and with reference to a
migratory flight between the points of north and south. Another
point may be noticed with regard to the spring migration to
which Herr Gatke calls attention, viz. the much smaller number
of certain species which pass the island at this period of the
year. This he accounts for on the theory that birds travelling
from their winter quarters to their breeding grounds take the
most direct route possible at this period of the year. The
majority, therefore, traverse lines of flight passing much to the
east of the island, and generally speaking, in a south-westerly
to north-easterly direction. Ingenious as the theory may be, it
is quite unsupported by any positive evidence, and is in direct
conflict with the author's assertion, expressed on page 25, that,
observations conducted on the island have established the main
facts that in autumn the migration is from east to west, and in
spring from west to east. As an instance that all birds do not
return in spring by the most direct route to their breeding
grounds, the Shore-Lark may be pointed out. This species passes
Heligoland at this period in considerable numbers by an appa-
rently west-to-east route, though its breeding grounds lie far to
the north of the latitude of the island.
To the writer, the great mortality which must of necessity
take place amongst birds, affords a much more probable explana-
tion of the fact of the smaller number of migrants being observed
in the spring. If we only reflect what the numerical increase of,
say, 100,000 pairs of birds would amount to in a few years, allow-
ing four young as the annual production of each pair, and the
young themselves breeding the following year, it is at once
evident that a single species would soon over-run the whole earth,
unless some check on its constant increase were not always in
action.
The position of the island may here, perhaps, lend an
additional explanation of the fact of fewer birds being observed
in spring. In the autumn many species will be nearing their
winter quarters, and consequently travelling very slowly and
lingering in any locality likely to afford rest and refreshment ;
55
but in the spring many, on the other hand, will only be just
starting on their journeys, and consequently not so urgently in
need of food and rest. Even the author's own theory that at
the latter period birds " perform their journey from their winter
quarters to their breeding-grounds, if possible in one uninter-
rupted flight" (p. 44), would lead us to expect fewer callers on
the island at this season than in the autumn.
With regard to the return of Siberian species, whose presence
on Heligoland is said to be due to the peculiar influence of certain
meteorological conditions prevailing at the time of migration, it
can only be suggested that as they have been led so much astray
by these causes, it is very doubtful, if they are ever capable of
finding their way back again to their proper breeding-grounds.
Most probably those which survive the dangers of winter join
parties of other species journeying to the north of Europe, where
the chances are very much against their ever finding a mate.
In conclusion, the migration of several species whose breeding-
grounds are in the far north, such as the Knot, Sanderling, Curlew
and Pectoral Sandpiper, &c., may be pointed out as evidence quite
at variance with the theory that their flights are conducted in a
broad front. In a small area like that of the British Isles, where
the distance of the central portions from the sea is so insignificant,
all these species are of the rarest occurrence inland ; whilst on the
coast-lines, more particularly the eastern, several of them are
very abundant. The same is the case in other parts of the world,
and it is only in the great river valleys, such as that of the Volga,
that they are met with in any regularity. The Knot, however,
though very abundant on the Atlantic coasts of America, is
almost unknown inland, even in a great river valley like that of
the Mississippi. All these facts are quite contrary to what might
be expected were migration performed according to the theories
of Herr Gatke.
56
ALTITUDE OF THE MIGEATION FLIGHT AND
METEOEOLOGICAL CONDITIONS WHICH IN-
FLUENCE MIGEATION.
HOUGH Herr Gatke has devoted separate chapters
in dealing with his observations on the altitude
of the migration flight, and the meteorological
conditions which influence migration ; to the
writer it seems a better plan to discuss both
features together, as they appear to him to be
so closely connected; and it is also stated in
many places by Herr Gatke that the height of the flight is
governed by the prevailing weather.
His opening words in Chapter III. are very important, as they
define his views of the normal height and manner in which
migration is performed. He remarks : " Observations extending
over many years have led me to the conclusion that, as long as
migration proceeds under its normal conditions, this elevation is,
in the case of by far the larger number, so great as to be com-
pletely beyond the powers of human observation ; while we must
regard as disturbances and irregularities of the migration move-
ment proper, due to meteorological influences, such portions of it
as are brought within our notice. Here I ought to remind the
reader that when I speak of migration proper I mean those
large extensive movements which, on the one hand, in autumn,
conduct our migrants from their breeding homes to, or very near
to, their winter quarters in one uninterrupted, and for the most
part, nocturnal flight ; and on the other hand, in spring, convey
them in the opposite direction from their winter quarters to
their breeding haunts the uninterrupted continuity of the flight
being still more marked in this latter phase of the migratory
phenomenon."
On page 53 he further remarks : "In the case of our small
57
Warblers, Thrushes and the like, this limit of visible elevation
may perhaps not amount to much." Of course a Thrush, or any
smaller bird, becomes invisible at only a very moderate height, but
one may perhaps be excused a feeling of surprise to read on page
76 that " Under normal conditions the migrations of most
species proceed at a height of at least 20,000 feet," or, roughly
speaking, a trifle less than four miles. When we recollect that
the highest mountain peak of the Himalayas does not exceed
29,000 feet, we get some idea of what the elevation must be at
which, according to the theories of the author, migration is
performed by the more robust species.
Having learned so much respecting the character of normal
migration, it becomes necessary to further inquire what is the
author's idea of normal and abnormal weather, for if the state of
the atmosphere governs the manner and height at which the
migratory flight is performed, then the latter can only be de-
scribed as normal or abnormal in a secondary sense, as it is the
direct outcome of the former.
On page 76 we find the following : " Birds naturally choose
for their migrations those strata of the atmosphere which offer
the most favourable conditions to their progress. It is, however,
a fact of peculiar interest, that during both migration-periods of
the year, all species, without exception, approach in largest num-
bers to the earth's surface when very light south-easterly winds,
accompanied by clear warm weather, happen to prevail for any
length of time in the lower regions of the atmosphere. If autumn
brings a long spell of weather of this kind, we may not only
reckon on the appearance of large numbers of all our common
visitors during September and October, but may also look forward
with certainty to the frequent occurrence of species very rare in
Europe, and originating from the far East. . . . from all
these facts it appears that the meteorological conditions discussed
above are those best adapted to the migrations of birds, and that
the latter betake themselves to strata of the atmosphere in which
such conditions prevail " (page 77.) Herr Gatke's remarks have
been previously quoted to the effect that visible migration is the
abnormal phase of the movement, but as the height of the flight
is governed by the prevailing weather in the light of his theories
58
it follows, therefore, that we are forced to the conclusion
that the prevalence of warm weather with light south-easterly
winds near the surface of the earth is also abnormal. And again,
as he also does not recognise such a fact as retarded or deflected
migration (page 75), then the constant prevalence of such condi-
tions of the weather before described, at some height or other,
becomes an absolute necessity to the performance of migration.
Let us just consider whether light south-east winds with
warm weather at the periods of migration can be fairly considered
abnormal. Herr Gatke himself has many remarks to show that
at one period during his long experience such meteorological
conditions were for many years the rule rather than the exception,
and he also gives us tables showing that these conditions prevailed
for long periods over immense tracts of land in Asia. Another
important point, too, must not be overlooked. There is absolutely
no evidence to prove that these same conditions do not prevail up
to great heights in the atmosphere at the same time as they
obtain near the surface of the earth. If such is the case, as seems
very probable, one naturally wonders why do birds perform their
migratory flights near the earth's surface, when there is nothing
to prevent their accomplishing their flight in the according to
Herr Gatke normal manner, or at the immense heights before
stated ? As this is not their custom, under these conditions it
seems reasonable to infer that they really prefer to migrate at
lower elevations. It will, perhaps, be readily admitted that
migration in the earlier stages of its development was conducted
at low elevations and in short stages, such as described by Herr
Gatke on page 46. Taking into consideration this fact as well as
the foregoing evidence, and also bearing in mind the wonderful
records of visible migrations presented to our notice by the author,
would it not be more reasonable to look upon the migration,
which is said to take place at such vast heights, as the abnormal
rather than the normal ?
It is difficult to understand how Herr Gatke postulates a
migration on a large scale at heights far beyond our vision.
His notes on certain birds rising to great heights on setting out,
refer to highly specialised species given to soaring at all times of
the year. To the writer he seems to base his theory on the
59
[negative evidence afforded by the absence of certain birds in
'particular years; direct proof is of course practically unattainable.
jThere is also another point worth noting. Herr Gatke describes
migration proper as being conducted at both periods of the year
jin one unbroken and for the most part nocturnal flight, the un-
| broken character being more pronounced in the spring than in the
j autumn. Why, therefore, do birds tarry at such an uninviting
little spot as Heligoland, when all the conditions are favourable
to the performance of this unbroken flight ? It may be pointed
out here, that while a migratory flight may be fairly called
unbroken which does not call at the island, if reference to Heligo-
land alone is intended ; still, for all that, there are many other
places where rests may be taken, but of which we have no records.
A reference to American statistics is all against this theory of an
unbroken flight (vide " Migration in the Mississippi Valley,"
(Cooke and Merriam, 1888).
Having examined into Herr Gatke's theories as to the con-
ditions most favourable to the performance of the so-called
normal manner of migration, the question naturally arises, by
what sense or by what means do birds, wishing to migrate,
make themselves acquainted with the state of the atmosphere
at the vast heights at which we are told they conduct their
journeys ? Supposing the winds at their winter quarters are, as
the time for departure approaches, of an unfavourable character
are we to assume, therefore, that as the impulse to migrate
becomes irresistible, that birds make voyages of discovery up
to great heights in search of favourable strata of the air, or
are they supposed to be possessed of some sense which will
enable them to detect the presence of favourable air- currents
at great heights without this faculty being rendered inoperative
by the unfavourable conditions prevailing at the time near the
earth? His further remarks seem to favour the latter theory,
for on page 78 he writes : " We can hardly admit that birds
seek such strata at haphazard; we ought rather to assume
that they are possessed of an inherent presentiment or sensi-
tiveness to distant but approaching phases of the weather.
We are supported in this view by the fact that many birds in
confinement manifest much unrest, by fluttering and by the
60
frequent utterance of their call-notes on days which precede
nights of strong migrations." It may, perhaps, be readily
admitted that the power of foretelling some twenty-four hours
ahead, approaching changes which will affect the weather locally
is possessed by the great majority of birds, and we can easily
understand how such a faculty has been acquired through the
process of natural selection. But is there any evidence to show
that this faculty is operative from the surface of the earth in a
vertical as well as a horizontal direction ? All changes in the
weather, according to the author, becoming first evident in the
higher regions of the air. The fluttering of a captive bird of a
migratory species on days preceding strong movements, may point
to nothing more than the periodically recurring impulse which
must be inherent in all such species. If we attribute this rest-
lessness, however, to a knowledge of a change in the atmosphere
which will bring about an abnormal migration abnormal both in
strength and character then we must assume that this sense,
which enables the captive to perceive the coming change, is only
operative at times corresponding to the usual periods of flight,
otherwise we should expect a similar exhibition of restlessness at
every coming change in the atmosphere. In the face of this
contention it seems more reasonable to attribute this restlessness
to inherited desire to migrate becoming active at these particular
times. If we grant that birds have the power of discerning the
state of the weather in the countries ahead of them, we can only
wonder why so many come to grief in performing their migration
prematurely. That this often happens there is abundant evidence
to show. Mr. Seebohm's experience of this premature migration
in the Valley of the Yenesay is a well-known instance. With
regard to Herr Gatke's remark that the sensitiveness of birds to
the first faint indications of an atmospheric change must be at
least equal to that of a good barometer, this may, perhaps, be
granted, as it is no uncommon thing to meet with human beings
who are able to predict with constant accuracy the state of the
weather for the coming twenty-four hours. This is accomplished
with no other aid than their natural senses. However, Herr
Gatke adds that f< we must not forget that in the elevated
regions in which their migrations proceed, birds are brought under
61
the influence of the slightest signs of an approaching change of
weather long before anything of the impending change is perceived
on the earth's surface, where the earliest indications of it are
probably not felt until about twenty-four hours later." He further
remarks " It can hardly be doubted that all changes of weather
have their origin in the higher strata of the atmosphere" (page
78). If birds have twenty-four hours' notice of a storm before
its approach is detected on the earth, through flying at great alti-
tudes, it is difficult to imagine why, considering the high rate of
speed at which they are supposed to migrate, that they do not
put forth their powers and convey themselves to a place of safety
without breaking their flight at all, or descending near to the
surface of the earth. In the light of this enquiry it will be
interesting to examine the behaviour of migrating birds on the
approach of one of these disturbances of the atmosphere as
described on pages 78-79.
After remarking on the familiar phenomena of the various
layers of cloud travelling towards different points of the horizon,
the author formulates the theory from a study of these move-
ments, that the appearance of light fleecy clouds at great heights,
traversing the heavens in an opposite direction to that of the
wind at the surface of the earth, predicates a change of the latter
to an opposite quarter. And as birds, according to his theories,
travel at these great heights during the normal performance of
their migratory flights, they would naturally become aware, or
actually meet with the adverse wind or conditions, " long before
anything of the impending change is perceived on the earth's
surface." At a time, however, when the winds at the lowest
elevations are light south-east, birds travel at only very moderate
heights, it must be supposed because conditions above are un-
favourable to so-called normal migration. It is difficult to see,
therefore, how, whilst they are flying low, they can become
acquainted with the first indications of the coming change, if
they are only at that particular period exhibited at the great
elevations before described ; for it is not until the west or south-
west wind gains the ascendancy at the surface of the earth
or in other words, that the coming change has taken place
we are told, that the migration passes into higher altitudes, its
speed being at the same time strikingly accelerated.
62
On occasions like these the number of birds which alight
during the morning hours, is at that time considerably diminished,
and the few birds that do so, soon start afresh on their journey,
so that by the time that the wind has completely changed to the
west and rain has begun to fall, not another bird is to be seen.
To the writer this all points to the fact that birds, on becoming
aware of the approach of a storm from the quarter to which they
are travelling, as a rule fly to meet it, and also hasten their speed
in order to reach a desired goal before it breaks over them.
In formulating his various theories, Herr Gatke appears to be
constantly under the impression that all birds which are passing
his observatory have already flown long distances without a
break before they come under notice.
If the relative position of Heligoland to the adjacent masses of
land is studied, and the observations of other ornithologists are
borne in mind, the opposite conclusion can hardly fail to be arrived
at, the majority of birds having probably only executed a short
flight before their arrival at the island. This must be especially
the case during the autumnal migration. As 'Heligoland presents
such limited accommodation for rest and food, they are com-
pelled to fly further on, in the face of the approaching storm, to
seek the necessary food and shelter elsewhere. It is difficult to
imagine, however, if at the time of starting they were actually
aware of the storm they would have to encounter on their
journey, why they should set out at all.
In the face of these considerations it seems more reasonable
to suppose that migrants flying towards a storm only become
aware of its approach about the same time as an ordinary
barometer at the surface of the earth would have indicated its
vicinity. The particular instance, so graphically described on
page 79, as occurring the third week of October, 1882, seems to
bear out this contention. Birds which had been migrating at
low elevations in large numbers for a fortnight previously, the
weather having been favourable, on becoming aware of the
approaching change, hurried forward at great speed to reach a
place of shelter before it burst upon them. Whilst the storm
raged no birds were seen at the island, but in the opinion of the
author, migration was not interrupted but continued in its normal
63
manner at great heights above, the atmosphere in these elevated
regions being supposed to have returned to a state of calm.
It seems hardly likely, however, that any birds would set out
to cross a wide sea under such conditions, and the appearance
of migratory flocks during a lull on 24th, when the wind had
considerably abated, points more to the fact that these individuals
had been merely awaiting a favourable opportunity to continue
their journey at some locality near at hand. Some light is
thrown on the theory that these migrating birds had only become
aware of the weather they were to encounter from indications
present at the earth's surface, from the fact that many of them
were Hooded Crows, a species which only under most exceptional
circumstances migrates at a height of more than a few feet above
the surface of the land. They, in any case, would not have felt
the first indications at a great altitude. The assertion, however,
that the Hooded Crows had become aware of the approaching
storm at a distance of 1,200 miles from the area in which signs of
the disturbance were then becoming evident, i.e., in the Hebrides,
depends entirely on our acceptance of Herr Gatke's statements
as to the rate at which this species migrates, and also as to the
direction from which the flocks are derived. The position of
their starting-point, i.e., 600 east of Heligoland, being purely
theoretical. Had they been coming from Scandinavia, as seems
more probable than from due east, then there might have been at
their point of departure local indications of the approaching
change some time before they became apparent in Heligoland.
So far from the first indications of changes in the weather
becoming first perceptible at very great altitudes, where the
air is very thin, it seems far more reasonable to suppose that
near the surface of the earth where the influence of the large
masses of land and water, coupled with the greater effect of the
sun's rays on the denser atmosphere, is the region where all
changes of the weather have their origin and become first
apparent. At any rate the appearance of light fleecy clouds
travelling at a great height in the opposite direction to the wind
prevailing at the surface of the earth, followed by others, at a
lower level and eventually culminating in rain, is hardly sufficient
evidence that the converse is the case.
64
It must not be forgotten too, that normal migration, according
to the author, is not only performed at a height of not less than
four miles, but is also carried out at a great speed, and to use his
own words " in one unbroken and for the most part nocturna
flight." This supposed possession of a sense enabling birds to
detect the state of the atmosphere at heights exceeding foui
miles, must, to be of really much use, greatly exceed the power
of a barometer in order to enable them to ascertain the meteoro
logical conditions they will encounter eight or nine hundrec
miles or more distant from their starting point, and that they are
able to do this there is no evidence to prove.
It must often happen, however, that changes of the weather
at the earth's surface do take place after such indications merely
as coincidences, in the same manner as a mass migration supposec
to be induced by a desire to escape difficulties in front, may
in reality be pushed forward into dangers ahead by causes in
the rear.
It must be by no means forgotten that all Herr Gatke's
observations on the weather have been conducted in the very
limited area in which he resides, and though there is no reason
for doubting the accuracy of his statement that birds migrate
nearest the surface of the earth during the prevalence of light
south-east winds, the fact must be taken to apply only locally.
A reference to the charts published in the daily papers referring
to the winds of the previous twenty-four hours, will very commonly
reveal the fact that the air- currents nearest the surface of the
earth are traversing semi-circular or even still more eccentric
paths. Thus a south-east wind at Heligoland may in the Baltic
have been travelling from the north-east and the same current in
the North Sea might be locally recorded as a south-west wind.
Herr Gatke also draws attention to the fact that the greater or
lesser quantity of moisture in the atmosphere has also an
important influence on the amount of visible migration. The
quantity of moisture in the air is generally determined by the
direction from which the wind has been travelling, .and also the
comparative areas of sea or land over which it has passed ; thus,
in the British Isles, winds blowing from quarters between the
points of north, north-west and due south, are, as a rule, heavily
65
charged with moisture, whilst, on the other hand, those from the
north, north-east and east are, as a rule, very dry. Winds from
the south-east, as regards the amount of rain which accompanies
them, are very variable, but the local observations of the writer
tend to establish the fact that a south-east wind of three or four
days' duration culminates in a downfall.
In presenting evidence in favour of his theory that south-east
winds are the most favourable conditions to the performance
of migration, Herr Gatke has been at considerable pains in
obtaining statistics that these winds prevailed over a vast tract
of country lying to the east of Heligoland during certain years
when the island was especially visited by a large number of birds
which he regards as migrants from far eastern Asia. However
interesting these tables are, their value is much diminished by
the absence of negative data. How are his readers to know
whether or not in other years, when the so-called visitors from
the far east did not visit, or only visited the island in very small
numbers, south-east winds did not prevail over the same tract of
country for nearly the same period? Another point must be
noted. Herr Gatke frequently refers to Eichard's Pipit as a
visitor from the countries bordering on the Amoor River, or the
shores of the Sea of Ochotsk ; he also refers to the Yellow-browed
Warbler in somewhat similar language, these two species being
supposed to be particularly affected by these south-east winds.
Now it does not seem to have occurred to him that a south-east
wind blowing in the districts named must have a very different
nature from the same wind at Heligoland. In the first instance
it will have passed over the Pacific, and so probably have become
densely charged with vapour, like the south-west winds of our own
islands ; and, in the second place, before reaching his observatory
it will have traversed large areas of land, and in the meantime
have shed its moisture on the intervening countries in the form of
rain.
To take the tables themselves. It will be found that on
examination of the statistics presented, though the preponderance
of winds during the first-named year, viz., 1847, blew from the
quarters said to be favourable to migration, still in the ninety-
one days under notice eighty-six observations of unfavourable
5
66
currents were recorded, thus illustrating that there was no real
constancy in any one direction. It has already been pointed out
that in Herr Gatke' s opinion it is these winds which have the
extraordinary effect of turning a small proportion of certain
migrating species from their normal course in favour of a long
land- journey to the west of Europe, from whence very few of
them ever return.
As an illustration of the danger of drawing conclusions from
the presence of a particular species of bird at the periods of
migration, without its full geographical distribution being known,
the following forms a striking case : In this particular year,
viz., 1847, to which reference has already been made, Herr
Gatke records the fact of the unprecedented number of Mealy
Redpolls which visited Heligoland. These he informs us were
mixed to the extent of about one-third with individuals of what
he terms the eastern form, i.e., F. exilipes ; further remarking
that Redpolls are altogether of an extremely rare occurrence
in Heligoland. The Mealy Redpoll, as is well known, is fairly
common throughout northern and north-eastern Europe, and,
moreover, is a very hardy species, and which ought to be con-
sidered perhaps more of a gipsy, than a regular migrant, and
to the writer there is absolutely no evidence that these flocks
came from the far east. With regard to F. exilipes the history
of the geographical range of this species or form will in the
opinion of the writer find its parallel in the cases of Anthus
Richardi and P. superciliosus at some future date when their full
extent is known.
Messrs. Pearson in their trip to Russian Lapland, found this
Redpoll breeding pretty commonly near the village of Lutni,
where they state it was the Redpoll of the district (Ibis, 1896).
No doubt further research will reveal the fact that it occurs
throughout northern Russia in comparative plenty. Thus it
seems far more probable that the large flights of Redpolls at
Heligoland in 1847 came from the north of Europe and not from
the far east. In passing it may also be pointed out that the
Northern Bullfinch is another species to which Herr Gatke also
alludes as an eastern one, as though it were absolutely confinec
to the continent of Asia.
67
It will be opportune here to quote Mr. W. Eagle Clarke's
remarks on the meteorological conditions affecting migration, as
presented in his " Digest of the Observations on the Migration of
Birds, 1880-1887." Mr. Clarke states at the outset that observa-
tions he has utilised have been constantly conducted and reported
from fifty-four stations distributed over western Europe, between
Haparanda and Bodo in the north, and Toulon, Biarritz and
Corunna in the south, as well as all parts of Great Britain and
Ireland. Mr. Clarke remarks : " When studying bird migration
in connection with meteorological conditions, it is essential that
the weather peculiarities synchronous with the setting in of the
migration, and prevailing in the particular area in which the
movement had its origin, should be considered. This alone has
any true bearing upon migration, not the weather prevailing
upon the shores reached after an extended migratory flight. . .
The weather influences are of two kinds. (I.) Ordinary weather
influence. It is found that in both the spring and autumn
migratory periods there are spells of genial weather without
marked features, other than those favourable for migration.
During these the movements of the various species are of an
even-flowing arid continuous nature. If the weather should
prove slightly unsettled during such periods, it is a matter of in-
difference to the migrants ; if more pronouncedly so, their move-
ments are slightly quickened thereby. This may be termed
normal migration under ordinary weather conditions.
The duration of such favourable spells, however, is sooner or
later broken by the advent of a cyclonic period of a more or less
severe type. This interferes, to a greater or lesser degree, with
the progress of the migratory movements.
(II.) Extraordinary weather influences. These are exerted by
the prevalence of particular weather conditions, which may act
either (1) as barriers to the ordinary movements, or (2) in
diametrically the opposite direction, as to incentives to great
movements, or " rushes," as they have been termed.
The weather barriers to bird migration, are unfavourable
conditions of a pronounced nature, which interrupt and make
impossible, during their prevalence, the ordinary seasonal
movements.
68
" The weather incentives to migration are widely different in
their nature, and may take several forms. First, there may be
favourable weather periods immediately following unfavourable
periods. Secondly, they may be due to weather in certain
respects unfavourable to the birds, such as a decided fall in
temperature, which either compels birds to move, or acts as a
warning that the time has arrived for their departure south-
wards. Such cold spells are characteristic of anti-cyclonic
periods, when the weather is calm and highly favourable for a
prolonged flight. Thirdly, and on the other hand, the advent in
spring of a genial spell, especially if accompanied by a rise of
temperature, is an incentive to a move to the northward for the
summer haunts.
" The weather influences thus vary considerably ; but tempera-
ture plays the most important part in the various seasonal
movements, and is the main controlling factor in all extraordin-
ary movements, other meteorological conditions being suitable.
Each movement, however, has its peculiarity, and the conditions
controlling it are often due to meteorological phenomena of a more
or less complex nature, most of which, perhaps, admit of
explanation."
Eef erring to the great autumnal movements of birds to
our eastern shores, Mr. Eagle Clark remarks, p. 20 "It has
been ascertained that all these great movements are due to
the prevalence in north-western Europe of weather condi-
tions favourable for migration. These conditions are the result
of the following type of pressure distribution, namely, the
presence of a large and well defined anti-cyclone over the
Scandinavian Peninsula, with gentle gradients extending in a
south-westerly direction over the North Sea. On the other hand,
cyclonic conditions prevail to the westward of the British area,
with a low pressure centre off the west coast of Ireland, or,
though less frequently, over areas further south. Under these
pressure conditions the weather is clear and cold, with light
variable airs over Norway and Sweden, while in Britain the sky
is overcast, and moderate and strong easterly winds are ex-
perienced, with fog not unfrequently prevailing at many east
coast stations.
69
" The formation of these conditions in the autumn usually
follows the passing away from Scandinavia the area in which
the movement has its origin of a spell of a more or less pro-
nounced cyclonic nature, during the prevalence of which the
ordinary course of the migratory movements is either interrupted
or rendered impossible. The effects of this sequence of meteoro-
logical conditions on bird migration are remarkable.
" During the cyclonic spell a weather barrier arrests the
progress of, and dams back, as it were, the ordinary seasonal
migratory stream. These periods, too, are not unfrequently
characterised by weather of great ungeniality, and this, no
doubt, gives the summer birds warning that the time for seeking
the south has arrived. Upon the duration and severity of these
preliminary conditions depends, to some extent, the magnitude of
the migratory movement that follows.
"The formation of the anti-cyclone removes the cyclonic
weather barrier, releases the flood, and provides conditions
favourable for migration, adding also an incentive in the form of
a decided fall in temperature."
Mr. Clarke then further illustrates how birds, starting under
favourable meteorological conditions, on nearing Great Britain
may fly into conditions the reverse of favourable, owing to the too
close proximity or the depth of the western low-pressure centre.
He further remarks on the exhausted condition in which many
birds arrive under these circumstances, also stating that no
doubt many sometimes perish during the journey. It will be
seen that Mr. Clarke's conclusions are quite at variance with
those of Herr Gatke, for in the light of the theories of the latter,
migrating birds, on encountering the low-pressure system and its
accompanying unfavourable winds, would not have their flight
retarded or altogether prevented, but would merely elevate its
path to regions above the disturbances and pass over the shores
of Great Britain at heights beyond our cognizance. On the
other hand, he confirms Herr Gatke' s statement that the
prevalence of easterly winds is favourable to the migratory flight,
but not in the same sense the latter asserts is the case. It has
been previously pointed out that Mr. Clarke's labours have
resulted in the opinion that Heligoland and Britain draw their
70
migratory hosts from different sources. The question of the
meteorological influences on an east-to-west autumnal move-
ment, via the latter isle, therefore, need not be discussed here.
In view of the fact that Herr Gatke attributes the presence
of many so-called far eastern species on Heligoland to the direct
influence exerted by the prevalence for any length of time of
light south-east winds, Mr. Eagle Clarke's remarks on winds in
general will be interesting. On pp. 25 and 26 he remarks : " The
importance attached to winds in connection with bird migration
has hitherto been much over-estimated by popular writers, and
their influence, such as it is, misunderstood.
" The conclusions to be drawn from a careful study of the
subject are : (1) that the direction of the wind has no influence
whatever as an incentive to migration ; but that (2) its force is
certainly an important factor, inasmuch as it may make migra-
tion an impossibility, arrest to a greater or lesser degree its pro-
gress, or even blow birds out of their course. We have the
clearest proof, indeed, that birds do not migrate when the winds
are exceptionally high, though they sometimes pass into high
winds and gales en route, under the meteorological conditions
which have already been described and explained. Ordinary
winds that is, winds not too strong appear to be of small
concern to the birds, for they are recorded as migrating with
winds blowing from all quarters."
The extracts presently quoted in this pamphlet will illustrate
the truth of the latter assertion.
Mr. Eagle Clarke further remarks : "It is, however, a fact
that particular winds almost invariably prevail during the great
autumnal movements, and these have hitherto been considered
by some as the direct incentive to such migrations. Such
is not the case, and it may be at once stated that these sup-
posed favourable breezes are simply another direct result of the
pressure distribution favourable to the movement. . . The
winds prevailing and dependent upon the barometric conditions
are easterly, chiefly south-easterly, breezes. There is really no
reason why westerly (west, north-west, and south-west) winds,
not too strong of course, should not, other things being equal, be
in every way as suitable for migratory movements as those
71
varying between such divergent points as north-east to south."
This, of course, does not affect the truth of Herr Gatke's statement
that migration is performed in greatest strength, or is most ap-
parent at the surface of the earth, during the prevalence of light
south-easterly winds accompanied by fine warm weather, but it
effectually disposes of his contention that these conditions form
the incentive to small numbers of certain eastern species to for-
sake their customary routes of migration in favour of a flight from
the far east to the far west.
Mr. Eagle Clarke further explains that strong westerly winds
are unfavourable to migration simply because they are the result
of types of pressure-distribution which are fatal to migration
between North-western Europe and Britain, i.e., the conditions
prevalent in the former area, during their prevalence, would be so
disturbed that birds would be prevented from setting out.
Herr Gatke, on p. 85, refers to the deterrent effect of fog on
migration at Heligoland. Judging from his remarks, fog either
prevents migrants from setting out at all, or induces them to
perform their flights at great elevations. This is not always the
case, however, for he mentions instances, both in his diaries and
in the present work, of birds in large numbers being heard
migrating above the fog.
Of course it is well-known that local fogs are far more
frequent than fogs of great extent which envelop large tracts of
land or wide areas of sea. Whilst the latter may prevent birds
from starting on their flights, the former can only have a very
unimportant influence on migration in general. It is easy to see,
however, how a fog surrounding so small a spot as Heligoland,
even if its extent was limited to the immediate neighbourhood
of the island, might so hide the latter from the view of passing
birds as to prevent them making their usual call.
With regard to the effect of fogs on the British coasts Mr.
Eagle Clarke remarks, that during their prevalence more birds
than usual approach the lanterns of lighthouses, and that many
are killed on such occasions. These facts point to the correctness
of the theory that migration, as a rule, is conducted at only
moderate elevations.
Reverting again to the altitude of and general conditions affect-
72
ing migration, there are certain species of very regular appearance
on Heligoland which Herr Gatke tells us always, or only on the
smallest number of occasions, perform their migrations at very
low elevations, viz., the Hooded Crow, Starling, and Skylark,
and in the opinion of the writer, the Lapwing, Fieldfare, and
Redwing might have been added to these. Are we to assume
that these species are devoid of that special sense of approaching
changes of the weather supposed to be possessed by the majority
of species, or is it more perfected in them, so that they are always
able to choose a favourable time for their journeys? The
evidence presented by the author rather points to the former
conclusion, for we read of Hooded Crows meeting with adverse
winds and Skylarks being overtaken by thunderstorms.
If there is one fact calculated to strike the reader in perusing
Herr Gatke's work more than another, it is the marvellous
number of birds actually seen or heard passing his observatory.
To the writer this fact alone is enough to make one pause before
admitting that visible migration is the abnormal and invisible the
normal. Those, however, who are also ready to agree with the
author in his theory of a broad migration front corresponding to
the breeding area, have to face in addition the incredible but
necessary myriads of birds which must exist to enable the latter
theory to be granted as even reasonably probable.
That certain species, such as Cranes and Hawks, fly at times
to great heights, is undoubtedly a fact, and it may readily be seen
that it is an advantage to the smallest birds to ascend to a good
height before crossing wide seas. For it must often happen that
they encounter sudden changes of weather which may materially
retard their progress. Nansen in crossing Greenland experi-
enced this at a height of over 8,000 feet a gale which had
been raging for two days suddenly blowing with only a pause of
a few minutes from the opposite quarter. It is very evident that
the further a bird has to fall, as its strength gradually fails, the
greater chance it will have of eventually reaching the land, of
course providing forward progression is not altogether impossible.
But to the writer the effort put forward to attain a vertical height
of four miles or more would, by the consumption of energy at the
outset, more than counteract the benefit before mentioned.
73
It once fell to the lot of the author to witness an extensive
migration of certain small species Finches, Larks and Starlings,
on the Norfolk coast, during the prevalence of very strong
southerly and south-westerly winds. At the point of observation
numerous flocks of Finches, principally Fringilla ccelebs and
chloris, were passing from north to south, closely following the
eastern shores of the Wash. These birds were flying at a good
speed and without any halt for rest, at a height of about thirty to
forty feet. The same may be said of the Starlings and Skylarks.
On one day, however, when the south-west wind was particularly
strong, flocks of Finches might have been observed coming in from
directly over the sea. These birds did not come headlong down
from a great height ; though they appeared when first viewed like
small specks of dust, just as described by Herr Gatke. Now
these latter flocks did not, on reaching the coast-line, alight for a
rest, but hurried on at the same elevation and in the same direc-
tion as the first-named flocks, thus plainly showing that they had
not reached their journey's end. It seems probable, therefore,
that it is only when passing over wide areas of sea that small birds
mount to any great height, and even then there is no evidence to
show that they rise to such altitudes as Herr Gatke endeavours to
prove, or that they will necessarily meet with conditions more
favourable to their migrations in the latter regions.
It will be interesting to compare the observations of other
ornithologists living in different localities on the winds most
favourable to visible migration with those of Herr Gatke. The
following extracts are taken from Mr. John Cordeaux's " Birds of
the Humber District " (pub. 1872).
Writing on the Short-eared Owl he remarks (p. 13) : " The
winter of 1865-66 was characterised by large arrivals of these
Owls, when after some heavy northerly gales during the last
fortnight in October many appeared at various localities along
the eastern coast."
Further on he quotes the following note by Mr. J. E. Griffith,
from the Zoologist. The latter observer remarks (p. 27): "I
write to inform you of the occurrence of the Blue-throated
Warbler (P. suecica) off the coast of Norfolk. While crossing
from Christiania to London by the ss. ' North Star,' we had
74
observed many birds performing their autumnal migration ; the
Wheatear, Titlark, and Eing Dotterel had been seen in mid-
ocean, flying easily against a light S.W. breeze. The number of
these migrants increased as on September 1st we approached the
Norfolk coast, many of them, as the weather was thick, settling
on the ship." Then follows a description of the Bluethroat. On
p. 37 Mr. Cordeaux has a note to the effect that in 1869 the first
flights of Goldcrests arrived at Spurn on the night of October
llth, wind N.W. to N. Again, on p. 70, writing on the migra-
tions of the Cuckoo, he states that " much depends on the nature
of the season ; a cold backward spring with a prevalence of
easterly winds always delays their appearance. A change in the
direction of the wind about the second or third week in the month,
from N. or E. to S. or S.W.,is certain to bring them northward."
His notes on the arrival of the Woodcock are particularly
interesting. On p. 123 he remarks : " With the prevailing winds
off the land in October from S. to W., it is never a great
Woodcock season on this coast, but strong winds blowing any-
where from the opposite quarters, from S.E. to N.W., and better,
thick, foggy, or drizzly weather accompanying these winds, are
invariably highly favourable to an abundant arrival of ' cocks '
along the eastern seaboard. The stronger the wind and the
wilder the weather from these quarters, the greater, as a rule, the
number of birds that may be found. It does not follow, however,
that these winds are the most favourable for the passage of the
Woodcock ; I am inclined to think the reverse is the case, and that
we shall find that the most favourable circumstances for their
crossing, as well as our other autumn visitors, are clear weather
and moderate winds from the W. or S., and that a long flight is
best kept up, and easiest sustained, either against a head wind
or one a ' few points free.' The fact that Woodcocks are always
most numerous at the period of migration on this coast during
the prevalence of strong north or easterly winds, shows that these
soonest exhaust their powers of flight, causing them to drop
directly they make land, instead of proceeding, as they doubtless
would have done, with a fair head wind, directly forward to
their winter quarters."
The above passage also throws some light on the height at
75
which Woodcocks travel, for, according to Mr. Cordeaux's
observations, they do not seem to rise to a strata of the atmo-
sphere out of the reach of the unfavourable winds before alluded
to, but to battle against them until they reach the land. In the
light of Herr Gatke's theories on the slight changes in the
weather which will influence the current of migration they should
adopt the former course.
On p. 123 Mr. Cordeaux has also a footnote to the effect that
at the period of the autumnal migrations our various migratory
species, both of shore and land birds, are invariably most abun-
dant on this coast during or after the prevalence of strong N. or
N.E. winds. Many observations on the varying character of the
winds accompanying migration might be culled from the
" Eeports on the Migration of Birds." The following may be
quoted (Sixth Eeport, 1884).
" East Coast of Scotland. Long spell of E. winds in April
and rushes, but a light S.W. wind on the 30th, changing from
S. to E., brought a 'wonderful rush of land birds.' This seems
to me [Mr. J. A. Harvie Brown] interesting, as proving the
station to lie in the direct route of' migration, rushes occurring
both in the most favourable winds S.E. or E. (i.e. for spring
migration), and those supposed to be less favourable, and
following winds, viz., S.W."
" A later schedule, April 30th to June 3rd, shows evidences of
a decidedly late spring migration, for which it seems difficult to
assign a cause. ... It took place in second week of May,
and with light S.W. and W. winds, mist, fog and rain ; princi-
pally of warblers and insect-feeding species." (Isle of May.)
" Inch Keith. This land-locked station returns a light sche-
dule, of considerable interest, however, as carrying out what has
been remarked by us in previous reports, that when birds do
occur here on migration it is usually with S.W. and westerly
winds, whether in spring or in autumn."
The following note refers to a strong migration at the Isle of
May, from November 4th to 6th. The wind was apparently S.E.
or S. at the commencement though the report does not actually
state the fact afterwards changing to W. The editor remarks :
" Mr. Agnew describes this as the largest rush of migrants this
76
season at the Isle of May, and it must have been very vast, close,
and determined, when even on the 6th, with light W. wind, large
numbers of Bramblings and Chaffinches still appeared." Other
notes to the same effect might be readily quoted, but the returns
from the east coast of England, which, as they include an area of
latitude identical with the island of Heligoland, should provide
the most interesting material for comparison. Thus we find :
Turdus viscivorus. Eedcar, October 4th. Flocks of Mistle
Thrushes coming in ; wind N.W.
Turdus iliacus. Between Earn Islands and Hasborough, L.
V., at various stations from October 1st to November 15th ; rushes
on October 21st to 24th ; wind S. and S.W. On the same dates
as the latter, numbers passed Heligoland, but the direction of the
wind there not stated.
Turdus pilaris. The following Heligoland note occurs :
December 1st, 24th, and 30th (S.W., still overcast). On the
latter day very large numbers, and with a N.W. wind : windy
and rain; an example of T. migratorius was reported as seen
quite close.
Turdus merula. Spring, at Northumberland stations, from
March 14th to 20th many ; wind W. and S.W.
In a foot-note the Editor quotes from a letter received from
Longstone Lighthouse as follows : " November 10th. All kinds
of small birds coming all day. . . . wind southerly; hazy
weather. . . . llth. Birds still coming ; all kinds, or rather
the small kind. . . . 12th. Great rush of Blackbirds, Ouzels,
Redwings, Lapwings, Grey and Golden Plover, &c. . . . This
is the greatest rush of the season, and lasted all day up to
10 p.m. Complete absence of Starlings. Wind all day from S.
to S. by W., after midnight changing to N.W." It is curious to
note that there was no corresponding rush across Heligoland
during the same period.
On p. 44 follows a very interesting note on Cyanecula suecica
(Arctic Bluethroat). Cley and Blakeney (as observed by Mr.
F. D. Power) : September 8th, W.N.W., one : llth, E. to
N.N.E., one shot, showing red spot fairly well ; 12th, E. to N.,
eighty to one hundred, also many Redstarts. . . . 13th,
E.N.E., about four dozen left on bank ; 15th, E., eight or ten ;
77
16th, S.E., and later, N.E., four or five. Spurn, September 15th,
I two seen, one shot ; 18th, three shot and others seen. Isle of
Thanet, September 13th, two seen. . . . Heligoland, August
31st, some young ; September 1st and 3rd, pretty numerous ; 9th
and 19th, very many ; llth and 12th, very great numbers, and
less to 18th, 19th and 20th. They were thus most numerous at
the latter locality at the same time as the largest flock was
observed in Norfolk. Commenting on this immigration of Blue-
throats to the Norfolk coast Mr. J. H. Gurney remarks : " It
would seem that the Bluethroats came in just the sort of com-
pany they might have been expected in, viz., with Tree Pipits,
Wheatears, Yellow Wagtails, and Greater Whitethroats, and
this company probably arrived with a light wind from the north.
On September 13th, the day before they were noticed, the wind
was light N. ; on the 12th it was light N.E., or E.N.E., and on
the llth it was N.N.E. ; on the 17th the wind was N.E., and they
probably left Blakeney, and migrating against it, got as far as
Yarmouth and Lowestoft 'denes.' On the 18th it was S., and
pursuing the coast southwards they most likely crossed the
Channel. . . . The two birds shot by Mr. Power on the 22nd
at Blakeney were I imagine, a later arrival, and if, as is most
probable, they came on the previous day, it was with a west
wind, i.e., a contrary wind. On the same day a Bluethroat
was shot on the coast of Northumberland, as I learn from Mr.
T. H. Archer, and the day before one was identified, but not shot,
at Tees mouth." Then follows an interesting foot-note in which
Mr. Gurney quotes Mr. John Cordeaux, to the effect that " it
may be laid down as an axiom that, with southerly or westerly
winds, not amounting to gales, normal migration to our east
coast in autumn is the rule (see * Eeport on Migration,' 1881,
p. 39). No wind at all suits small birds best. It seems, when
bent on migration, they will make the passage with a light cross
wind, but very rarely indeed with a wind which is due in their
favour." The opinions of two such experienced observers as Mr.
Cordeaux and Mr. J. H. Gurney will naturally be held in great
respect, but it will be seen that they are in conflict with that of
Herr Gatke, who states that on the prevalence of light E. winds,
i.e., winds due in the favour of birds, migration across Heligo-
78
land to our east coasts then takes place in greatest strength. In
view of Herr Gatke's remarks on the direction of winds most
favourable to visible migration, which he states are from E. or
S.E., or some points approximating thereto, it will be interest-
ing to note to what extent birds are seen to pass Heligoland
when winds are blowing from so-called unfavourable quarters.
In the seventh " Eeport on the Migration of Birds " for the year
1885, will be found a complete diary referring to the island,
compiled by himself for that particular period.
The following entries will show that considerable migration
takes place almost under all conditions of the atmosphere :
"February 26th. S.W., early fog; p.m. clear, fine. Corv.
frugilegus ten thousands, Cornix few, Sturnus many, Merula few,
Alauda passing on overhead. . . . Fr. chloris, cannabina,
coelebs many, particularly first. . . . Ant. pratensis and
rupestris many. . . Ch. auratus, vanellus and hiaticula, Fr.
alpina and Num. arquata all migrating in great numbers."
Then follows a curious commentary on Herr Gatke's state-
ment as to the most favourable winds.
" February 27th. S., S.S.E., forenoon fog; p.m. clear, fine.
All the above, but less in number." One would naturally have
expected greater numbers, owing to the favourable change of
wind.
" March 5th. N.W., light overcast. Corvus frugilegus and
Sturnus, not many. . . . Al. arvensis very many. . . .
Char, vanellus thousands, auratus hundreds. . . . Num.
arquata and Tringa alpina many.
" March 9th. N.N.W., windy, cold, now and then fine snow,
and clear. Corv. cornix little flights. . .
" March 15th. N.N.W., windy, cold, overcast ; in evening
fog till 1.30 a.m. F. merula tolerable. . . . Sturnus flights.
. Vanellus early, some flights. . . *
" March 16th. W., violent, cold, overcast ; in evening clear.
Corv. cornix six to ten, Sturnus till nine in morning ; flights of
hundreds and thousands. Merula a few hundreds. . . .
Al. arvensis many, Char, vanellus and auratus passing on over-
head. . . . Tr. alpina early, great flights. From two o'clock
till day-light at lighthouse. Sturnus vulgaris extraordinary
79
many. . , . . Merula very many. Alauda, Ch. vanellus and
auratus also very many ; also ducks.
" March 27th. S.S.W., violent, overcast, cold ; in evening,
ten o'clock, fog. Corv. cornix early, a few great flights.
Col. palumbus pretty many ; Vanellus early, pretty many ; Scolo-
pax twenty to thirty been shot."
On the previous day the winds were light S.E., but unac-
companied by any remarkable migration, except in the case of
Alauda alpestris, which passed in great flights.
" March %Sth. N.N.W., slight, early overcast ; later clear,
fine. Cor. cornix single flights, Sturnus some flights, Merula
pretty many. . . . Al. alpestris some flights. Woodcocks
140 to 150 being shot.
" March 29th. Northerly, light, clear, early hoar frost. Mone-
dula, frugilegus pretty numerous. . . . Merula early, pretty
many ; Mot. alba several small flights ; Ant. pratensis and ru-
pestris pretty many ; Scolopax, about twenty shot.
" March SOth. E., S.S.E., slight, clear, fine ; early, veryjsharp
hoar frost ; in evening E.N.E., cool. All the above, but in little
numbers.
" April 3rd. N.E., fresh, cold, clear. . . . Al. alpestris
pretty many.
"April 4:th. N.E., slight, cool, clear; in evening E. by S.,
cloudy. . . . Al. alpestris pretty many ; Scolopax, forty to
fifty being shot. Then follows a day with S.E. winds.
"April 5th. S.E., fresh, thick, cloudy; hasty clouds, low,
loose ; cold. Early not a bird ; during day few Starlings,
Thrushes, Hedge-sparrows, and Shore Larks."
Then follow records of the 7th and 8th, with winds chiefly
E., but accompanied by only moderate migration. On the fol-
lowing day (9th), wind E. by N., slight, weather good, clouds
from S.S.E., the numbers of passing birds had materially in-
creased. Amongst the arrivals were two Bluethroats.
" April Wth. Easterly, light, thick, fine rain ; in evening, W.
and W. by N., light. During the past night, from two o'clock,
very many Turdus and Saxicola migrating. During the day
extremely many of all the above species passing over the sea (i.e.,
C. cornix, Monedula, Al. arvensis, alpestris, Mot. alba, An.
80
pratensis, &c., &c.). Fring. coelebs, montifringilla, and cannabina
in uncountable numbers the whole day.
" April llth. Easterly, light, dull, very fine drizzly rain.
Much migration on this date. Early in morning Peewits, Plover
and hiaticula extraordinarily numerous."
Then follows the interesting entry on the 12th, with a light
S.E. wind, dull and overcast conditions very favourable to
strong migration " altogether, little migration."
On the 13th wind N. by E., slight, clear ; passing birds
were fairly numerous.
On the 15th, 16th, 17th and 18th, with winds S.E., almost
calm; E. early, slight; E. and N.E. very fresh, clear, wind
cool ; E. by N., fresh, clear, a little warmer ; on the above
respective dates, migration is described as " very little, or
extremely little."
On the 19th, however, wind "E. by S., S.S.E. slight, quite
clear, warm." There was an extraordinarily numerous migra-
tion of Hooded Crows, accompanied by other species in fair
numbers.
On April 20ta, with S.W. wind, clear, and W. and N.W.
freshening up ; in evening, light. There appears to have also been
considerable movement going on, as the following entry for 21st
will illustrate : " W.N.W. and N.W. During past night exten-
sive migration of all Longshanks." It is worthy of note that
this took place under conditions said to be least favourable to
the performance of visible migration.
Turning now to the autumn movement we find the following
interesting entries :
"September 9th. S.W., windy, rain, low clouds; W., high
clouds in evening; N.W., violent squalls. Mus. luctuosa, Sy.
phoanicurus and trochilus, pretty many, in spite of the south-
west wind and rain. In night, stormy thunder, lightning, rain
and hail.
" September 10th. W. by N. and N.W., stormy, rain squalls ;
in evening light. luctuosa, phoenicurus, trochilus, pretty many
in garden under shelter of shrubs.
" September 18th. E. by N., moderate, overcast; in evening,
N., fine, cold. During the past night much migration " (wind on
81
17th, p.m., E.N.E.). Then follows a list of species, with remarks
on their abundance, the final comment being, "Altogether, very
strong migration."
September 19th. A fairly strong migration occurred on this
date also, with winds from W. to S.W.
September 25th. On this date, with westerly winds, light,
heavy cumuli, showers of rain with hail ; in evening, light
northerly. Several species were passing in considerable num-
bers, others also fairly plentiful. Herr Gatke makes the following
significant remark: "It is striking that with such monstrous
heavy cumuli that have the appearance of storm clouds, so much
migration takes place. There must be better weather at hand."
However, this prophecy was not realised at once, for the 26th
dawned " draught of air southerly, still so heavy, threatening
cumuli at W. and N., but in spite thereof much migration." The
movement was, however, increased in strength on a change of
wind to " S.E., light, clear."
September 28th. There was a further change in the wind to
to " E.N.E., slight, light clouds, sunny," accompanied by much
migration.
On September 29th a storm was notified from America to
occur between 28th and 30th. If birds are able to foretell a
coming change of this nature, we should have naturally expected
them to have hastened their migration in order to escape the
storm. However, there was very little movement on this date,
though the winds were from the S. by E. light; later fresh,
S.E. clouds ; p.m., wind S.W.
On September 3Qth, with winds, "early, light N.N.W., clear;
|p.m. S. by W., thick, windy " almost nothing at all.
Broken weather prevailed from October 1st to 6th, accom-
panied by very little migration, except a great flight of Snow
Buirtings on 3rd (wind S.W., thick, very stormy) and a few
Par us major and cceruleus.
On the 7th the winds were N. to N.N.W., "better, clear;
later, violent with rain squalls." There was an extensive migra-
tion of Hooded Crows and Starlings on this date, accompanied by
other species in smaller numbers. Many Larus minutus, too,
were observed at sea off the island.
6
82
On the llth, with winds E.S.E., moderate; a.m., rain;
p.m., clear; in evening, E.N.E., light, clear. There was a large
migration of several species. This was continued in lessened
volume on the following day, with winds changing from N.N.E.
to S.W., with rain showers.
October 15th appears to have been a very changeable day, the
weather being described as " S.E., slight, clear, middle high clouds
from W. by S. ; noon, light, cloudy, wind E. by N., clouds from
S. In evening, E. by N., violent, clouds from S. by E. In
night, E., very violent, thick clouds from S.E. This erratic
weather was accompanied by very strong migration of several
species, and the author appends the following note : "According
to the weather in the morning, there ought to have been con-
siderable migration Thrushes and Woodcocks but prominent
westerly currents in higher regions acted adverse." It is difficult
to understand, however, why these species should not have taken
advantage of the " most favourable conditions " which prevailed
at the time in the strata of the atmosphere nearest the earth's
surface, for in the night of the 16th, during the prevalence
of the violent weather before described, there occurred an
" extraordinary strong migration of Larks, Thrushes, Starlings,
Numenius and Charadrius."
On the 17th the winds and weather are described as northerly,
light, quite thick with rain, low loose clouds slowly from N.W.
and N., after midnight, dead calm. " During the early hours
until 9 o'clock extremely large flights of Thrushes flying about
high, just as if bad weather was approaching." However, the
predicted storm did not take place, for the following days appear
to have been pretty calm and at times even sunny.
It is difficult to account for the behaviour of these Thrushes
on Herr Gatke's theories as to the height at which migration is
performed. Here we have unfavourable conditions to visible
migration prevailing near the earth, i.e., northerly winds quite
thick, with rain and low loose clouds slowly from N.W. and
N., and yet these Thrushes did not seek favourable conditions
in the upper strata of the air, but fly about the neighbourhood of
Heligoland instead of continuing their journey in the normal
manner, at a height of 20,000 feet or more.
The above extracts will sufficiently illustrate the fact that
while Herr Gatke's statement may be correct, that birds when on
i their journeys approach nearest to the earth when winds from
the E., S.E., or E. prevail, it by no means follows that exten-
sive migration is not to be witnessed under entirely different
! conditions, i.e., at times when the winds prevail from quarters
j described as least favourable. It will also be gathered that winds
I from E., S.E., or S., are not of necessity accompanied by move-
ments of birds, as one might imagine from the theories of the
author, such winds in whose opinion form the incentive to
exceptional migration from the far east.
Herr Gatke makes some interesting remarks in connection with
the special organisation of birds ; which becomes a necessity
if his theories as to the vast heights at which their migrations are
performed, are accepted as correct in order to enable them to
sustain the cold they would naturally encounter, and to overcome
the difficulty of respiration, owing to the thinness of the air.
He remarks (p. 47) : " Birds, therefore, must be organised in
such a manner as, on the one hand to be uninfluenced by so con-
siderable a diminution of air-pressure as one meets with at
heights from 25,000 to 30,000 feet ; and on the other hand, they
must be able to exist on the considerably reduced supply of
oxygen obtainable in strata of such rare density." The means
by which these difficulties are overcome are, in his opinion, the
possession of a system of air-sacs, which communicate with the
lungs. Setting aside for the moment the fact that, with the ex-
ception of certain highly specialised birds, which are at nearly all
times of the year, given to soaring about at great heights, and that
it still remains to be proved that the smaller species really attain
such great altitudes during migration ; it will be interesting to
learn in what manner these air-sacs can be of such assistance to
birds in performing their annual flights. In connection with this
point, Herr Gatke remarks (p. 47) : " Probably owing to the
possession of these air-sacs, the flight of birds in the higher strata
of the air is so much facilitated that they are enabled to apply
the muscular power of their instruments of flight almost exclu-
sively to the execution of their forward movements. This results
partly from the fact that by the filling of the air-sacs the volume
84
of the bird is enlarged, and its specific weight considerably
diminished, but also from the air taken in at any particular height
being warmed by the heat of the body, and considerably rarefied
in consequence, so that the contents of the air-sacs are always
considerably lighter than the air which occupies surrounding
space." To the writer several fallacies appear in the foregoing
arguments. In the first place, any increase in the volume of the
bird must also mean increased resistance to its passage through
the air, and again, admitting that it is possible for a bird though
it is very difficult to conceive how it can be accomplished to so
regulate the action of its wings that nearly all the effort is
expended in furthering its forward movement, it seems that this
gain would also be counteracted by the loss of wing-power, owing
to the lessened momentum obtainable by the wings from the
surrounding rarified air. This is important when it is remem-
bered that in Herr Gatke's opinion a speed of anything from 100
up to 200 miles an hour is maintained by nearly all species o:
birds throughout a flight of many hundred miles.
Herr Gatke appears to hold the opinion, when he speaks of th<
air in the air-sacs always being warmer than the surrounding
atmosphere, that their contents can be retained without change
for some considerable time. To take in a stock of cold air anc
then to warm it by contact with the body means also to expanc
it, and unless a constant change is going on it appears to the
writer that the retention of a supply of expanded air for any
length of time, without changing its identity, would be an abso
lute inconvenience to a bird. Herr Gatke also appears to hole
the view that this warm air in the air-sacs means increased
buoyancy to a bird. But according to Dr. Drosier, practica
experiment has proved that in a pigeon weighing ten ounces, th<
gain in this respect would only amount to the fraction of a grain
In the opinion of the latter gentleman the air-sacs are a necessary
part f the respiratory apparatus of birds. He makes the further
statement that they are present in all species of birds, even such
as do not fly. However, it is only fair to add that Herr Gatke
gives only partial adherence to the theories he has advanced, foi
he remarks (p. 48) : " More exact calculations based on physica
laws, have undoubtedly compelled us to recognise that this warm
85
change of air in the air-sacs of birds is unable to facilitate their
flight to any considerable extent. Nevertheless, long continued
observations in Nature have convinced me that birds must be
endowed with a certain capacity for soaring or floating in the air
which is independent of the use of their external instruments of
flight." Unfortunately he is unable to throw any light beyond
the above suggestions, as to the nature of these aids to flight.
That he, however, in the main attributes this capacity to the
possession of the air-sacs will be gathered from his further re-
marks on p. 72. In the interesting account of his observations
on the soaring upwards of a Buzzard and the appearance of
Sparrow Hawks as they descended to the island, some light is
thrown on another point, viz., the limit at which certain species
of birds might be migrating without our being able to see them.
Thus we find the before-mentioned Buzzard disappeared from
view at a height of at least 12,000 feet, and a Sparrow 7 Hawk
appeared as a speck at 10,000 feet. Now bearing in mind that
these elevations amount to about half the estimated height at
which so-called normal migration is performed by the vast
majority of species, it will not be unprofitable to calculate at
what heights other kinds of birds would become lost to our view.
We may fairly reckon the larger of the European Turdinse at less
than half the size of a Buzzard. Thus they should disappear at
a height of 6,000 feet or less. The smaller species would equal
half the size of a Sparrow Hawk. We should, therefore, lose
them at 5,000 feet or so. Chaffinches, Pipits, Wagtails, Fly-
catchers, and the larger Warblers are about half the size of a
Song Thrush. They would become invisible at 3,000 feet.
Whilst the delicate Phylloscopi and Gold-crests would be dis-
appearing from view at a height of only 1,500 feet or less. It
will be gathered, however, from Herr Gatke's remarks on p. 56
that it is not the largest species which migrate at the greatest
elevations. For he includes " species allied to the Snipes, such
as Curlews, Godwits, Plovers and their relations, as coming
next in respect to the height of their migration flight in order
to those already enumerated," i.e., Song Thrushes, Eed-breasts,
Hedge Sparrows, and Golden-crested Wrens.
It will be readily admitted that an exceptionally keen sight
86
would be necessary in order to distinguish a Willow Warbler at
500 yards distance. Why Herr Gatke should have placed so
high an estimate on the altitude of the migration path in the
case of smaller species, without more direct evidence, it is diffi-
cult to imagine. All he tells us on this point is "in the case of
the vast majority of migrants, both on arrival and departure, the
vertical elevation at which they appear and disappear invariably
represents the limit to which human vision is able to penetrate."
When we read, however, (p. 76) " that the migrations of most
species proceed at a height of at least 20,000 feet " under the
so-called normal conditions, we see what a very wide margin
there is between the latter estimate and the elevation at which
all but the largest species would disappear from our view.
It may be further noted that this power possessed by birds of
floating about or soaring upwards, which is said to be indepen-
dent of the wings, in the opinion of Herr Gatke, finds its antithesis
in the means by which certain aquatic birds are enabled to swim
with the body completely immersed. To the writer it appears,
that in comparing the two performances he quite overlooks the
fact of the great difference in the density of the surrounding
mediums. Whilst the inflation of the air-sacs in flying may
make a very trifling difference to the buoyancy of a bird, their
deflation in the vastly denser medium of the water, in conjunction
with minor actions, may fully explain the means by which the
latter act is accomplished. In needs very little reflection, to at
once see that to deflate the lungs and the air-sacs, and at the
same time expel the warm air, by compressing the outer coating of
feathers, from the downy covering of an aquatic bird, means greatly
lessened buoyancy. As an illustration of this, no better example
could be found than that of shot birds, whose respiration in the
meantime having ceased, and the latent heat of the body rapidly
being lost, a few minutes after death lose all their buoyancy and
merely float on the surface of the water like any other light object.
Birds are generally supposed to have descended from some half-
reptilian progenitor of aquatic habits, and the opinion may
perhaps be hazarded that the air-sacs may, to some extent, be a
survival of organs which found their greatest use in remote ages.
In commenting on the possibility of migration being retarded
87
or deflected, Herr Gatke refers to the practical utility of keeping
records of the arrival and departure of birds in particular
localities, which he thinks are of very insignificant value. The
following remarks are curious but interesting. After noting the
impossibility of effectually watching a district of four miles in
diameter, he writes : " The case of Heligoland is of course
different, for here we may say without hesitation that literally not
a single bird escapes observation." It will not be forgotten that
in another place he has expressed the contrary opinion, that the
number of rarities captured on the island is certainly exceeded
by those which have not been detected. He further adds
" Notwithstanding, the results of notes of this nature can never
amount to anything more than a list of such disturbances and
interruptions of the main migration movement at the particular
place of observation. . . From this, however, we are not able
to form more than an approximate conclusion as to the actual
duration of the migration, since we can never determine whether
the first observed individuals of a species are in reality the
inaugurators of the migration at that particular time, or whether
they may not have been preceded weeks before by a vanguard
travelling, according to the normal manner of the migration flight,
at great and impenetrable heights above." Then foUows the
following significant statement " On the other hand, it would
appear to be extremely unsafe to base on observations of this
nature, the line of arrival or the migration front of a species, or
to draw conclusions from them as to the velocity of the migra-
tion flight. . . For in the first place, it cannot be determined
whether one is dealing with individuals whose spring migration
is proceeding in a northerly direction, and not with such as are
pursuing an easterly course ; and, further, one cannot establish
with any degree of certainty, whether the first observed indi-
viduals of a species are actually the breeding birds belonging to
the particular district of observation or not."
The truth of Herr Gatke' s contentions is self-evident, though
there are localities to which, in studying the migrations of par-
ticular species, they would not apply. As an instance, the colony
of Pied Flycatchers in the Lake District of England may be
pointed out. It certainly would not be very difficult to trace the
migrations of this clan of birds during their progress through
England, or to detect the first arrivals. However, as a general
rule the force of Herr Gatke's arguments may be readily admitted.
But if they are applicable to nearly all other districts, they should
certainly still more forcibly refer to Heligolander, for hardly a
single land-bird migrates there to breed. All of the vast hosts
passing are migrants pure and simple, and whether they call or
not, " Time gone by, birds gone by," as the Heligolanders say,
is of no consequence. The full significance of Herr Gatke's re-
marks will be realised, however, when we remember that it is
on data of this nature that he bases all his speculations on the
velocity of the migration flight, the breadth of its front, and the
identity of certain flocks of particular species which pass his
island, with colonies of breeding birds in the north, or wintering
residents in the south. As striking instances of this, the cases of
the Northern Bluethroat and Hooded Crow may be pointed out.
Herr Gatke closes his long and interesting chapter on
" Meteorological Conditions " with a lament on the smaller
number of birds now observed at his observatory than was
formerly the case. However, when we read of " tens of thousands
of Books," " thousands of Lapwings," " extraordinary many
Eedbreasts," " astonishing numbers of Wheatears and Chaf-
finches," " Bramblings and Linnets passing in uncountable
numbers the whole day," followed by " uncountable numbers " of
Lapwings, "extraordinary many" Snipes and Ringed Plovers,
and Hooded Crows, and so on ad libitum, in describing the
spring migration of 1885 ; not to speak of great flights of Snow
Buntings, Starlings, and Skylarks, with " Hooded Crows in
hundreds of thousands," and Chaffinches in " thousands upon
thousands," followed by " extraordinary many " Song Thrushes,
and Ring Ousels, in the autumn one cannot but feel that
Heligoland is still the most highly favoured spot on the earth for
the study of the wonderful phenomena of bird-migration.
89
VELOCITY OF THE MIGEATION FLIGHT.
ERE, GATKE'S remarks in previous chapters on the
uninterrupted character and great elevation of the
so-called normal migratory flight of birds will
have prepared his readers for high estimates as to
the speed at which their journeys are accomplished.
These high estimates, indeed, are quite a necessary
sequence : for he also informs us that these un-
broken flights are performed by birds with their stomachs entirely
devoid of food. It is doubtful, though however much one might
be inclined to agree with the former theories if anything he has
previously written will have prepared his readers for the astonish-
ing results as detailed in the following paragraphs.
Exception will be taken by many to his opening words on
p. 63, where he remarks : " Many birds are able to follow the
different pursuits of their life only by daylight, and become the
most helpless of creatures as soon as darkness has set in. With
the advent of the migratory period, however, their whole nature
is changed to such a degree that after sunset they will soar to
heights hitherto unknown to them, and on pitch dark nights are
able to fly towards the goal of their wanderings with unfailing
certainty. Similarly, the speed at which their ordinary daily
locomotions in the air are performed has not even an approxi-
mate relation to the wonderful velocity of flight attained by
them during their migration."
It will be gathered from the above statements that in Herr
Gatke's opinion, the whole nature of a bird, including its powers
of flight and vision, become entirely changed, or at any rate
greatly augmented, during the periods of migration. In the light
of this contention his allusion to the marvellous speed of indi-
90
viduals passing across the island to the oyster beds, four miles
away, which he estimates at 200 miles an hour is curious. For
these latter flights, it will be gathered, are merely undertaken in
the daily search for food, and are not portions of a migratory
journey. It is a pity that he does not think well to bring forward
evidence on behalf of the assertion that birds become the most
helpless of creatures as soon as darkness has set in, for observa-
tions all point to the contrary being the case. It need perhaps
hardly be pointed out that many groups and species of birds
become very active in seeking their food at dusk. The Ducks,
Herons, Crakes, Eails, Bitterns, Plovers, Nightjars, and others
amongst the larger species may be pointed to as instances, and,
amongst the smaller are the Common Swift, various Warblers,
such as Sedge and Eeed Warblers, Nightingale, and also the Sky-
lark. The latter named, however, are not active in search of food
after sunset, but are ready at all suitable times during the breeding
season to break into song, and, however dark the night, on being
disturbed are able quickly and without difficulty to fly to a neigh-
bouring haunt, where they are as vociferous as before.
As an instance of the keenness of sight possessed by Ducks,
the writer has witnessed on several occasions, when a flight has,
after sunset, visited a small sheet of water, partially frozen over
with very thin ice hardly to be distinguished from the open water,
that they pitched directly into the latter without the least hesita-
tion, the open place, moreover, not being situated in the centre
of the pond.
At the periods of migration, especially in the spring, there is
no such thing as really a dark night, and even in the winter,
when migration for the most part has ceased, pitch-dark nights
are very exceptional, and in the experience of the writer, who
does not claim any special gift of sight, it is rarely that the
outlines of hills and woods cannot be distinguished at consider-
able distances. Coast lines, rivers and sheets of water, of course,
will be still more readily discerned. It may be pointed out here
that on the approach of cold weather, after a protracted mild
spell during the winter, and long after the periods of migration
are over, certain species make what may be termed supplemen-
tary migrations. These are frequently witnessed at Heligoland,
91
as elsewhere. Now it follows if these supposed augmentations
of sight and endurance were peculiar to the ordinary migratory
periods, that these supplementary movements would have to be
made without their aid. They are not, however, observed to be
conducted in any different manner to the seasonal nights.
During the prevalence of fogs, conditions are necessarily quite
unfavourable to any ordinary vision. Whilst it may be denied
that the powers of sight possessed by birds during the periods of
migration are augmented beyond ordinary times, it may be
readily granted that the speed of flight they put forth may be
considerably greater than that during the ordinary courses of their
lives. But that at the latter period this speed is not always at
their command, or, at any rate, is not increased by any special
change in their organisation at the former time, must, in the face
of the clearest evidence, be accepted as a fact. When a Plover
or other species, capable of very rapid flight, is attacked by a
Falcon it naturally exerts itself to the utmost to escape, and a
wonderful increase in the speed of its flight is apparent ; but as the
Falcon still gains upon its prey, the latter has recourse to twist-
ing and turning, simply because the limit of its speed has been
reached, and is, in many cases, of no avail. Under the influence
of fear it is natural that a bird will exert itself to the very utmost,
and may attain to a marvellous velocity of flight. It may also
be granted that at the periods of migration similar efforts may
be made, but nothing that has yet been witnessed in an encounter
between a Falcon and its prey can be said to approach to the
tremendous velocities attributed to certain small species during
their annual flights, according to the theories of Herr Gatke.
In commenting on the evidence furnished by the speed
attained by domestic Pigeons, as illustrative of the powers
known to be possessed by birds, Herr Gatke has, to the writer,
fallen into a very simple error. Accepting the statement that
100 geographical miles an hour was accomplished by a Carrier-
Pigeon from Ghent to Eouen as accurate, he remarks, in com-
paring the possible powers of the progenitor of the latter, i.e.,
the wild Bock-Dove : " It cannot be doubted that the flight
capacity of the domestic form must have fallen far short of that
of its primitive wild ancestor." This, he thinks, must be the case
92
owing to its having been in a domestic state for so many genera-
tions. He quite overlooks the fact, however, that in this parti-
cular strain the efforts of breeders have been directed towards
one goal, i.e., obtaining the fastest possible flyers. To accom-
plish this, for many generations artificial selection has been
unceasingly at work, breeders mating only their best birds. It
seems, therefore, more probable that, as in the case of the wild
horse and English race-horse, the domestic Carrier-Pigeon can
beat its wild progenitor, the Bock -Dove, in regard to the speed
of its flight. Von Middendorf's calculations on the speed of
migrants, to which Her Gatke objects, may be taken as fairly
accurate in spite of the remarks of the latter. But they refer to
another feature of the phenomena i.e., what may be described
as the rate at which the breeding grounds are re-colonised every
spring. His estimates will be found to be confirmed by the
researches of American ornithologists (vide "Bird Migration in
the Mississippi Valley," Cooke).
The Hooded Crow has been singled out by Herr Gatke as a
species performing its migratory flights at a very high rate of
speed. This is the more astonishing, as the heavy, plodding
character of its flight is well known. Even Herr Gatke himself
alludes to it as an " apparently sluggish flyer." It is surprising,
therefore, to learn that his estimate of the speed attained by this
species is no less than one hundred and eight geographical miles
an hour. It will therefore be very interesting to learn how he
has arrived at such a result.
On p. 67 he writes : " This bird, which without question,
must be classed among the less expert flyers, travels in autumn IE
innumerable droves across Heligoland and past both sides of the
island. The first flocks arrive about eight in the morning, and
are succeeded in undiminished numbers by flock upon flock until
two o'clock in the afternoon, all travelling without interrupting
their flight, in a westerly direction. According to the reports
of my esteemed friend, John Cordeaux with whose observations,
conducted on the opposite east coast of England, I am in the
habit of regularly comparing my own the first flights arrive
at that coast about eleven in the morning, and the last at about
five in the afternoon ; the latter being followed sometimes by
93
solitary stragglers. It has been repeatedly shown, and cannot
any longer be subject to the least doubt, that the flights of these
birds, which on this island appear far off on the eastern, and
disappear on the western, horizon, are the same as those which
arrive on the English coast from an eastern direction. Accord-
ingly, these sluggish flyers pass over the three hundred and
twenty miles of German Ocean in three hours, which gives a
velocity of nearly one hundred and eight geographical miles per
hour. This instance of migration speed is the more surprising,
inasmuch as it is displayed in the case of a bird which one might
almost caU clumsy, and which certainly gives no evidence of
corporeal dexterity."
The identity of the Hooded Grows passing Heligoland at
eight in the morning, with the flocks reaching Lincolnshire at
eleven, may be proved to the satisfaction of Herr Gatke. But
to the writer it seems rash in the extreme to formulate a
theory of so great a velocity of flight on such slender evidence.
Even if we admit, though few will be inclined to do so, that
the Hooded Crows passing Heligoland, or at any rate a small
portion of them, eventually reach Lincolnshire, what evidence
is there to show that the journey is accomplished by the most
direct route, or in an unbroken flight? If, as does not seem
unlikely, the first flocks which are observed to pass the island
about eight in the morning are, as Herr Gatke points out,
derived from the shores of Schleswig Holstein, from whence
they have started some half an hour previously, then thoso
which follow them until two in the afternoon assuming that
they in turn have started from some other locality about the
same time as the first will have already travelled, estimating the
rate of their speed at the same rate, viz., one hundred and eight
miles an hour ; some six hundred and fifty miles. Now the first
flights are not supposed to go much further than the east coast
of England after passing Heligoland, or, say, some four hundred
miles in all ; whilst the last flights, in order to reach the same
locality, will have travelled nearly one thousand. Does it not,
therefore, seem more probable that the first flights which reach
Lincolnshire about eleven o'clock in the morning, are derived
rom some locality in Western Europe, where they have rested
91
the night, before crossing the North Sea? The evidence which
may be gathered from Mr. Eagle Clarke's digest of the observa-
tions collected from the lighthouses and lightships by the Com-
mittee on Migration, altogether favours this view.
We are not told that this speed of 108 miles an hour is
attained under any special conditions as regards strength and
direction of the wind, so we may fairly assume that the feat is
accomplished during the prevalence of ordinary weather. In
Herr Gatke's opinion the Hooded Crow is more indifferent
than the majority of species in this respect. It naturally
happens, however, that sometimes winds are encountered which,
while they do not arrest their flight, still modify the manner of
its performance in a peculiar way. On p. 27 we read " During
the autumn migration it frequently happens that when out at
sea they are carried into air currents stronger than is suitable to
their line of flight, a violent south-east wind being especially
unfavourable to their normal progress. To escape the disagree-
able experience of having this wind blowing through their plumage
obliquely from behind, they turn their body southwards, and
appear to be flying in this direction." This is, however, only
apparently the case, as we are told that " their flight is con-
tinued in as exact a westerly course and with the same speed as
though the birds .were moving under favourable conditions
straight forwards," i.e., a speed of 108 miles an hour.
The italicised portions of the above extract will shed con-
siderable light upon the actual rate at which these Hooded
Crows are travelling. It will be granted that a gale blowing
with a force equal to fifty or sixty miles an hour will fairly cover
the widest estimate of the force of the before-mentioned "violent
south-east wind." But it is difficult to see how a wind travelling
at this rate could blow through the feathers of a bird flying with
a velocity equal to 108 miles an hour. A cyclist could have given
Herr Gatke a hint here, and at the same time have drawn a
more accurate estimate of the speed of these Crows. A rider
travelling at the rate of sixteen miles an hour with a twelve-mile
breeze behind him is quite unconscious of the latter were it not
for the movements of surrounding vegetation. Indeed he will,
even under these favourable conditions, be aware of a slight
95
resistance to his progress through the air, due to his own speed
being greater than that of the breeze at his back. It hence
follows that if these Crows turn their bodies to the south to
escape the disagreeable experience of the wind blowing obliquely
through their plumage from behind, that they must be travelling
at a lower rate of speed than the latter to produce this effect.
After reading for the first time and reflecting upon these
high estimates of the velocity attained by birds, as put forward
by Herr Gatke, the writer thought it would not be uninteresting
to time the number of wing-beats per minute performed by
the present species during its daily flight, under ordinary condi-
tions. Eepeated observations gave a result of from 190 to 200.
If we take the latter number as the basis of a simple calculation,
we shall get as a further result 12,000 beats accomplished in
an hour, during which period, in the light of Herr Gatke' s
estimate, 108 geographical miles should be covered or at the
rate of sixteen yards for each wing-stroke. Now the latter him-
self has classed the Hooded Crow amongst the less expert flyers.
But a speed covering a distance of sixteen yards for each
beat of the wings, or forty-eight yards per second which, as has
already been pointed out, is necessary to accomplish a flight of
108 miles an hour would have the appearance of a very swift
gliding motion. The latter is certainly not the character of the
flight of the Hooded Crow, nor could such a flight be classed as
other than expert.
Turning now from a robust bird like the Hooded Crow, to
a dainty species of less than one-eighth its bulk, and to which
Herr Gatke attributes the power of attaining a still higher and
more incredible velocity of flight during its annual journeys, i.e.,
the Northern Bluethroat. This is said to reach the astonishing
speed of 180 miles an hour, in the case of the flocks passing
Heligoland, and a still greater velocity in other instances. There
is no other species to which Herr Gatke makes more frequent
reference throughout his work than to this charming bird. It
will, therefore, .be interesting to here sum up the full extent of
the performances it has to undertake in order to accurately fulfil
all his speculations.
The more the latter are studied, the more involved in
96
difficulties they become. It will be necessary to recapitulate a
little in examining the feats this poor bird is required to accom-
plish. On p. 37 the Northern Bluethroat is cited as a species
performing its migrations from its breeding grounds in the north
to its winter quarters in the south, in a rigidly-adhered-to, north -
to-south line of flight, and in a broad column whose front corres-
ponds to the longitudinal area of the former district. We are also
told that Heligoland forms the most western limit of this migra-
tion front, and that the Bluethroat only in the rarest instances
deviates from the aforesaid direction of flight. In spring the
migration is conducted in a similar manner, but the direction of
the flight is of course reversed. At this period of the year, if
the weather be fine and warm, the bird is an abundant visitor
to Heligoland. May 26th, 1880, is a date pointed out when
this was especially the case. On this occasion " all the gardens
of the island teemed with them to such an extent that their
numbers in the nearest gardens were adjudged above five
hundred." This gives a good idea of the numbers of Bluethroats
migrating by this particular fly-line. It is further stated (p. 265)
that during its spring passage from Central and Northern Africa to
the north of Scandinavia, in the absence of cold and dry northerly
winds at the end of May and April, it appears on Heligoland as
a daily visitor, and if, in addition, the weather be fine and warm
with a light south-east wind, it frequently occurs on days of this
kind in such large numbers that as many as from thirty to fifty
males have been obtained. The migration thus lasts one month.
We also read that the Northern Bluethroat travels only during
the night, setting out at dusk and ending its journey at daybreak,
or immediately after sunrise. Hence, being unobserved in inter-
mediate localities, it accomplishes a flight of more than 1,600
geographical miles from Egypt to Heligoland in the course of a
spring night of scarcely nine hours, giving the almost miraculous
velocity of 180 geographical miles per hour. The further fact
that this bird is never seen during the night by the lantern of the
lighthouse is cited as an additional proof that the long migration
from Northern Africa is performed in one uninterrupted flight
(p. 45). It will be noted that the flight is first stated to travel
between Central Africa and the north of Scandinavia, but in
I 97
other places is said to be conducted no further than the west of
Central Norway (p. 66). It will be also gathered "that the
species does not winter further west than Central Africa, nor do
its breeding quarters extend further to the westivard than Norway,
there can therefore be no doubt as to the identity of the examples
found in Heligoland with those from Central Africa," (p. 66).
Before discussing in detail these various passages in the life-
history of the Bluethroat as observed at Heligoland, it will not
be inappropriate to remind the reader of Herr Gatke's own words
(p. 59) on the danger "of basing on observations of this nature
the line of arrival or the migration-front of a species, or to
draw conclusions from them, as to the velocity of the migration
flight," &c., &c.
First in order, it will be as well to again examine the evidence
in favour of a rigidly performed flight from north to south or the
reverse, according to the seasons, for in the opinion of the author
this is only departed from in the rarest instances, and it is on the
accuracy of this theory that his estimates of the velocity attained
are in the main dependent. Writing on the autumnal flight he
remarks (p. 37) " It hence follows most decisively that the bird,
in autumn, rigidly adheres to a southerly course of migration,
and travels in a broad migratory front which corresponds to the
longitudinal range of its nesting area, and of which Heligoland
forms the most western limit. Even a slight westerly deviation
from their southerly course of such species (individuals?) as
breed in the west of Norway could not fail to convey large
numbers of these birds to the east coast of England, and their all
but total absence there furnishes therefore an undoubted proof of
the persistency with which the southerly course of migration is
in this instance adhered to." As previously observed, Herr
Gatke's information relating to England is quite at fault, for
recently hardly a year passes without records of the occurrence
of the Bluethroat on our east coast curiously enough, many of
them coming from the pen of Mr. John Cordeaux, to whose notes
he so frequently refers. He has also quite ignored the consider-
able flock which arrived on the north Norfolk coast in September,
1883, though the latter fact is fully recorded in the reports issued
by the Committee on the Migration of Birds, and he himself
7
98
alludes to it in the chapter on the Reed Bunting (p. 380). He
further adds that the present species has never been met with in
France and Spain. The paucity of observers in the latter
countries would sufficiently account for this, though as regards
Spain the statement is not quite accurate, Colonel Irby stat-
ing that the Northern Bluethroat has occurred near Malaga
and Valencia, on the authority of Arevalo (" Ornith. Straits of
Gibraltar ").
It will be further found that the winter quarters of this
species which are variously stated by Herr Gatke to be located
in Egypt, North-eastern and Central Africa (to what part of
Africa the latter designation is to apply is not very clear), and
again, on p. 267, referring to those which nest in northern
Europe, in Egypt, Nubia, and Abyssinia do not lie in a relative
position of due north and south to the breeding grounds. The
flight, therefore, of a flock from the north of Egypt to the Dovre
Fjeld, in Norway which, according to Herr Gatke, is the locality
where the Bluethroats calling at Heligoland breed will not cross
the island at all unless a considerable westerly deviation takes
place beforehand. Its course would, however, cross the Alps ;
and may the latter fact not give us a clue to the non-observance
of the species in intermediate localities? As has before been
pointed out, might not these Bluethroats " rest in some lofty
Alpine valley" as Herr Gatke suggests is perhaps the practice of
other migrants, in his charming opening words on p. 1. This
consideration is, apart from the fact of the extreme paucity of
observers in Italy. It must also be noted that in comparison
with the extent of the breeding grounds in Northern Europe, the
winter quarters of the Bluethroat have a very narrow longitudinal
area; there must, therefore, be considerable lateral spreading,
both to the east and west, on the part of the various flights as
they perform their spring journeys.
A few words must be again said as to the identity of the flocks
passing Heligoland with the colony breeding in the Dovre Fjeld
in Norway. Herr Gatke expects his readers to take this fact for
granted without his putting forth the least evidence in its favour,
beyond his own theory that the migrations of this Bluethroat are
performed in a rigidly-adhered-to, south-to-north line of flight.
99
When we read of this species passing Heligoland in large
numbers, including a few adult males, as late as May 26th, and
which are said to be en route to a district in the most southern
locality of its breeding range, shall we not be justified in assum-
ing rather that flocks travelling so late are migrants to districts
in the far north of Scandinavia? As has been before pointed
out, Messrs. Seebohm and Harvie Brown record the arrival of the
Bluethroat in the Petchora Valley many hundred miles further
north on the 22nd of this month, by which time, no doubt, the
Bluethroats in the Dovre Fjeld will have commenced breeding
operations. Moreover, the numbers in which, under favourable
conditions, the species is observed, and the duration of its
migrations, i.e., end of April to end of May, also point to the fact
that the Bluethroats passing Heligoland are travelling to many
different localities in Norway and Lapland. How can we, there-
fore, accept the statement that it is the westernmost extremity of
a broad advancing migratory column alone which touches the
island ? Would it not be more reasonable to assume that the
Bluethroats migrating to Northern Europe from their winter
quarters in Egypt are travelling in many narrow streams, and
that the fact of their non-observance in intermediate countries to
the south of Heligoland is partially owing to this mode of flight ?
In connection with the latter point, the evidence of other
authorities quoted by Herr Gatke (p. 265) are interesting, and
point to the possibility that with an increased number of observers
the Bluethroat might be found regularly occurring in many inter-
vening districts. He remarks : " Kespecting Northern Germany,
Sylvia suecica has, according to recent statements, not only
been met with in isolated instances ; but surprising as it may
appear, has actually remained to breed near Waren, in Mecklen-
burg, and near Emden in Friesland."
As additional evidence in favour of the unbroken character
of the flight of the Bluethroat, the fact of its never having been
observed at the lantern of the lighthouse is cited by Herr Gatke.
But what does this prove ? Might not flocks which had broken
their journey in some previous locality pass over the island at
a considerable height ? If this should occur they would not be
likely to be attracted by the glare of the light.
100
The foregoing is a summary of the evidence upon which we
are asked to accept the statement that the Bluethroat during its
spring flight attains a speed equal to 180 miles an hour. On
p. 65 Herr Gatke writes as though he had actually witnessed
the performance of this feat, for he remarks: "This little bird
proved to be capable of flying during its migrations at the rate of
one hundred and eighty geographical miles an hour."
This is not all, however, for the acceptance of the " broad
migration column" theory lands the reader in further difficulties
and requires certain flocks comprising other portions of the
flight to accomplish still higher velocities.
If we merely take the north coast of Egypt as the starting
point of these migratory Bluethroats, and not Southern Egypt,
Nubia or Abysinnia, and bear in mind that according to the
theories and statements of the author, normal migration is
conducted when meteorological conditions are favourable, in one
unbroken flight from their winter quarters to their breeding
grounds in Northern Europe within the space of one short spring
night, it follows that if thousands occur on a little spot stated
to be in the track alone of the most western extension of the
migratory column, it also follows that east of this locality,
individuals should be travelling in equal abundance. Roughly
speaking Heligoland is fifty miles from Schleswig Holstein and
from the east coast of the latter for a considerable distance in
the same direction the Baltic extends ; a wide expanse of sea,
unbroken by islands forming convenient resting places. The
Bluethroats, therefore, comprising the corresponding portions
of the column, must necessarily fly still further and further before
they reach any locality on which they can alight. Moreover, we
are told the species only flies by night setting out from Egypt
at dusk and landing at Heligoland an hour after sunrise. It
follows, therefore, that the more eastern sections of the flight
which have to travel the greater portion and in some cases the
whole length of the Baltic, must develop a speed more than
double that of their more fortunate companions in the west of the
column, though the latter have the least distance to accomplish.
It will be gathered too that in certain seasons the latter owing
to unfavourable conditions, do not themselves break their
101
journey at Heligoland. We must assume, therefore, that on
these occasions the migratory flocks are aware at the outset of
their journey of the difficulties they will meet with, and put forth
the necessary additional effort in order to travel the longer distance
within the given time. No doubt Herr Gatke had these possibili-
ties in his mind when he remarks on p. 69 " there is hardly a
doubt but that the velocity of its migration flight may even
exceed this already remarkable figure," i.e., 180 miles an hour.
With regard to the statement that the Bluethroat does not
migrate by daylight, no account has been taken in the foregoing
argument that so late in the spring as May 30th, there is no such
thing as darkness from Central Scandinavia northwards.
From a comparatively feeble species we now turn to one
whose powers of flight, along with that of its congeners, are well
known, viz., the Virginian Golden Plover. There will not be
any diffculty in believing that this bird is able to accomplish long
flights at a high rate of speed, when atmospheric conditions are
favourable. But there are probably few readers of Herr Gatke's
work who will be prepared for the statement that this Plover
accomplishes an unbroken flight of fifteen hours' duration over a
distance of 3,200 geographical miles, or at the rate of 212 miles
an hour. This is, however, an indisputable fact according to the
assertions of the author. He has arrived at his conclusions from
the following evidence. He remarks (p. 68) "Flocks consisting
of thousands of these birds have been met with at a distance of
400 geographical miles and more east of Bermuda, flying in a
southerly direction on the way from their breeding places in
Labrador to Northern Brazil. The distance between the coasts
of the two countries amounts to 3,200 geographical miles, and
since there is along this whole stretch of route, not a single
point on which the travellers could alight for rest, they are
obliged to perform the whole length of this enormous journey
in one uninterrupted flight. We may probably assume fifteen
hours as the longest spell during which a bird is able to remain
on the wing without taking sustenance of any kind. On this
assumption, the velocity of flight of the above named birds
would amount to 212 geographical miles per hour."
He further adds" The case of the American Plover just
102
discussed, further shows how little in need of rest birds are
during their migration flight. Large sections of the migratory
streams of these birds which are directed towards South America
fly across Bermuda in immense quantities. As long as fair
weather prevails not one of these birds rests upon its migration
journey ; only a storm will induce them to alight (J. M. Jones,
naturalist in Bermuda). This, too, in spite of the fact that they
have already travelled over a distance of 1,200 miles from Labra-
dor." In view of this evidence, why assert that the time during
which a bird can maintain its flight without food and rest is
limited to fifteen hours ? Of course the power of abstaining from
food for any length of time will vary both with individuals and
species. It may, however, be pointed out that the birds of prey
are credited with the ability to undergo abstention for several days
without their being weakened thereby. A plover might not be
able to accomplish so much as this, but forty-eight hours does not
seem an impossible period even to the latter, the migratory flight
being continued in the meantime. The hordes of birds which
sometimes arrive on Heligoland late in the winter, which have
been fairly driven from other haunts by the absence of food,
and which arrive in the emaciated condition described by Herr
Gatke, are still capable of making flights of considerable length.
Nearly all species wintering in the British Isles, for a period of
three months, undergo a daily fast averaging fifteen hours' dura-
tion. For from mid November to mid February, roosting time is
about 4 p.m., and birds are rarely on the feed before 8 a.m. the
following morning. In foggy weather the period of fast is often
greatly lengthened. Of course they are at rest all the time.
It is of little moment as regards the extent of time during
which the particular species under notice could remain on the
wing, for Herr Gatke points out that there is nothing to prevent
their resting on the surface of the sea, even when moderately
agitated, as other species have been observed to do.
But all these estimates of speed, and powers of abstention
and endurance, are based on pure assumption, the same is the
case with the assertion that these particular flights of plovers are
travelling from Labrador to Northern Brazil. It is the theory of
a broad migration front travelling in a rigidly maintained north to
103
south line of flight over again. What evidence is there beyond
this mere theory, that the birds breeding in Labrador are identical
with those flights observed at, or near to, the Bermudas ? Even
if this could be proved it would not be sufficient, for it would still
be open to question whether they do not, on starting from their
breeding grounds, follow the coast line south, perhaps for hun-
dreds of miles before setting out over the sea. There is at this
season of the year no reason for any great haste in reaching their
winter quarters. According to further evidence quoted by Herr
Gatke certain flights of these plovers observed on migration five
to six hundred miles east of the Bermudas were variously stated
to be travelling due south and south east, thus illustrating in the
latter case that the flight is not conducted rigidly between the
points of north and south.
In the opinion of Herr Gatke no surprise need be felt on
learning that the Virginian Golden Plover accomplishes its
migrations at a speed of 212 miles an hour. Observations on
Heligoland, he tells us, prove that Plovers, Curlews and Godwits,
which fly across the island at a rushing speed during bright,
warm afternoons in early summer, are seen to reach the oyster
bed over four miles to the east, within the space of a single
minute. It would be interesting to know how the flight of these
individuals has been followed for so great a distance. In
England a curlew a mile away, in the pure atmosphere of the
Northumberland moors, is a very diminutive object.
Some light may be gleaned of the way in which the Virginian
Plover conducts its spring migration from the report on "Bird
Migration in the Mississippi Valley " (Cooke, 1888), where it is
stated that this species " Breeds in the Arctic regions, and occurs
on migration throughout the Mississippi Valley and Manitoba."
Now the breeding grounds will not be ready for occupation, at
the earliest, until the first week or middle of June, yet we read :
" In the spring of 1884, at Caddo, Ind. Ter., the first came about
March llth ; between March 21st and 27th it was noted from lat.
39 in Missouri to lat. 41 42' in Iowa and to Chicago, 111. Then
no more records were made until after the April storms. About
April 16th it began to move again, and April 24th it was reported
from Unadilla, Nebr. and Leeds Centre, Wis. ; April 29th, it
104
reached Heron Lake, Minn., and the first week in May was
reported from Argusville and Larimore, Dak. In south-eastern
Dakota it is very abundant during migration." A similar account
of the migration in the spring of 1885 then follows.
It will be at once apparent that the species commences its
migrations long before the breeding grounds are ready for occu-
pation and moreover the journey so far from being performed in
one unbroken flight, is undertaken leisurely and in comparatively
short stages. Of course this throws very little light on the actual
speed at which the various stages are covered, but if this is the
character of the migration at the time when birds are said by
Herr Gatke to exhibit unrest and impelling haste " Here we
nowhere meet with any attempts at dividing the long migration
flight into short convenient stages," he remarks (p. 4). Would
it not, therefore, be safer to assume that the autumnal journey
is uncharacterised by one great unbroken flight from the breeding
grounds to the winter quarters in South America, but is per-
formed more leisurely and in shorter stages which do not necessi-
tate a speed of 212 miles an hour for their accomplishment
within a given theoretical time ?
The Virginian Plover is not the only American species which
performs its spring migration in the foregoing manner. The
Pectoral, the White Bumped, Bairds', Least, and Semipalmated
Sandpipers ; and the Hudsonian, and Eskimo Curlews, may be
mentioned in addition. No doubt if it were possible to make
observations throughout the whole of Northern Africa similar
facts would be obtained relating to European birds. The un-
civilised condition of the greater part of the latter locality,
however, precludes the possibility of doing so at present. In
America conditions are happily different.
In a later chapter (Exceptional Migration Phenomena) Herr
Gatke discusses the incident of examples of the American White-
winged Crossbill having been observed crossing the Atlantic in
a locality many miles from land. This occurrence may, perhaps,
throw some light on certain of his theories as to the length of time
a bird can remain on the wing without food, and in the meantime
maintain great muscular exertions. The account of this incident
as recorded by Professor Newton, in the last edition of Yarrell's
105
4< British Birds," is to the effect that when about 600 geographical
miles east of Newfoundland, flocks of this species were observed
by Dr. Dewar, crossing the Atlantic before a stiff westerly breeze.
Many of the flocks alighted on the rigging of the ship, and of
these twelve examples were captured. Occurrences of this kind
are so common in the North Sea that Professor Newton very
reasonably suggests the opinion that many other migrants may
have been thus helped across the Atlantic by human aid ; with
what success may be inferred from the American element in the
list of so-called " British " birds. This does not meet with Herr
Gatke's approval, however, who remarks : " We cannot, however,
reasonably admit that cases like that just instanced explain the
passage of American migrants to Europe generally." He takes it
for granted that these flocks of Crossbills undoubtedly reached
the coast of Europe in safety long before their imprisoned com-
rades. To accomplish this it will be as well to see what feats
the former would have to perform.
Herr Gatke tells us that all migrants start on their journeys
with empty stomachs. We may, therefore, reasonably assume
that these Crossbills were no exception to the rule. The stretch
of ocean between Newfoundland and Ireland covers sixteen
hundred geographical miles, with no intermediate resting-place.
To cover the distance in the time he assigns as the limit during
which a bird can remain on the wing without food and rest, viz.,
fifteen hours, will require a speed exceeding 100 miles an hour.
Now, according to his observations on Heligoland, a stiff westerly
breeze would be unfavourable to the performance of migration
at low elevations, birds rising to vast heights during the pre-
valence of such conditions near the earth. These Crossbills,
however, were flying so low that they took advantage of the
presence of the ship which afforded them an opportunity for a
rest. This species, moreover, is by no means an expert flyer.
Does it seem at all probable, therefore, that under the adverse
conditions encountered these flocks actually reached the west
coast of Ireland in safety ? Could a Crossbill, even under favour-
able conditions, fly at the rate of one hundred miles an hour,
and maintain this velocity for sixteen hours without a break ?
Common observation has revealed the fact which is confirmed
106
by instantaneous photography, that the majority of birds fly with
the plane of the body slightly directed upwards. The mainten^
ance of a high rate of speed when a strong wind is blowing from
behind, becomes therefore almost a necessity. For whereas the
before mentioned position of the body enables a bird in meeting a
moderate wind to sustain itself in the air with a minimum of effort,
it will have the contrary effect with a wind blowing from behind,
unless the speed attained by the bird is much greater than the
force of the latter. It is very doubtful, however, whether a poor
flier like the Crossbill would have sufficient strength to maintain
a great velocity for any length of time. A stiff westerly breeze
would not, of course, even approach a force equal to 100 miles an
hour.
Herr Gatke has formed the opinion that birds are not in the
habit of breaking their journeys during either migration flight
until after the greater part of the distance has been covered.
He seems to have come to this conclusion from the fact of the
very short stay the great majority of species make on visiting
Heligoland. " After a night's incessant flight," he remarks, " a
greater or smaller portion of the succeeding day is all the birds
need for satisfying their hunger or recovering from such fatigue
as may have resulted from the exertions of their journey. I
myself have never noticed cases of fatigue or actual exhaustion
such as people tell about birds of the Woodcock family on this
island, in regard to any birds which have landed here during
their migration either by day or night." To the writer, in view
of the numbers of dead birds washed up on our shores, and the
observations of other ornithologists, amongst whom Mr. Eagle
Clarke's remarks are especially interesting (vide "Digest of the
Observation on the Migrations of Birds "), the above statements
are good evidence that the majority of the callers at the island
have travelled over only comparatively short distances prior to
their arrival at Heligoland. Indeed, the position of the island,
surrounded as it is on three sides by large land-masses at only
moderate distances, lends itself to this view. Those species
which breed in the north are undoubtedly governed in their
forward movement by the early or later departure of winter in
the lands towards which they are travelling. The late Mr.
107
Seebohm's observations in the Yenesay, some four hundred miles
from its mouth, form undoubted proof of this fact. As he awaited
the break up of the frost at a post on the Arctic circle, he notes
that prior to the melting of the ice on that great river few birds
arrived. As soon, however, as this commenced migrants in small
numbers immediately appeared. Some too eager to advance had
to retrace their flight. We cannot think that any of these, in
their far-off winter quarters were aware of the state of the
weather some thousand or fifteen hundred miles to the north.
Undoubtedly they migrated to the verge of the frost at some
much earlier period, and had followed its daily retreat to the
north until his post of observation was reached, their journey being
governed by the break up of the ice, which in Mr. Seebohm's
opinion takes place at the rate of one hundred miles a day.
The intrinsic weakness of Herr Gatke's theories on the
velocities maintained by birds during their migratory flights will
be apparent, when he has to call in their aid : " The assistance of
other factors besides the mechanical instruments of motion with
which the bird is equipped " (p. 72), to make these accomplish-
ments possible. His concluding words to this chapter are peculiar
and significant. They read as follows : " In treating of the height
of the migration flight, we have considered in detail that birds, as
distinct from other warm-blooded creatures, are provided with a
respiratory mechanism enabling them to remain for any desirable
length of time in regions of the atmosphere so rare in density
and poor in oxygen, as must necessarily result from elevations
extending to 40,000 feet ; and we have further seen that they are,
in addition, provided with a very extensive system of air-sacs
which they are able to fill or empty at pleasure. . . . Their
sole purpose, therefore, is evidently to enable them to perform those
wonderful migrations wonderful, both as regards the height at
which they proceed, and the velocity with which they are carried
out. If birds were restricted during their autumn and spring
migrations to the same low strata of the atmosphere in which
they move during the rest of the year, such of them as have to
perform their migratory journeys early in the spring or late in the
autumn would, in many cases, be obliged, in consequence of stress
of weather, to let the proper period of their migrations pass with-
108
out having been able to make a start on their journeys." The
little aid furnished by the air-sacs to a bird during its migration
has already been pointed out, and apparently recognised by Herr
Gatke. It is probably true that they may be filled or emptied
at pleasure, but whether a bird has the power of retaining their
contents or keeping them void is quite another matter. The
objection that birds might be so detained by stress of weather
unless they performed their migrations at great speed and at a
great height as to prevent their reaching their breeding grounds
at all, is overcome in so simple a manner, i.e., by their migrating
in shorter or longer stages as opportunity allowed, that it is
rejected by Herr Gatke, apparently for this reason alone. " To
withdraw themselves," he further adds, " from the disturbing
influences which are apt to prevail in these changeful lower strata
birds mount up into the more elevated layers of the atmosphere,
in which more uniform conditions prevail, and which are less
subject to powerful meteorological disturbances. In this way,
however, they reach elevations at which the resistance of the air
is so insignificant as to render possible the astonishing velocity
developed during the migration, while this velocity at the same
time counteracts any tendency towards sinking, a slight elevation
of the anterior margin of the horizontal wing surface being amply
sufficient to effect this object."
All of this has already been commented upon, but why the
author should imagine birds must ascend to these heights to
accomplish their migrations, when in the light of his own
assertions a sluggish flyer, like the Hooded Crow, or an expert
one, like the Virginian Plover, can develop respective speeds
amounting to 108 and 212 "geographical" miles an hour, at a
height of only a few feet above the surface of the land or sea,
is most difficult to surmise.
109
THE CAUSE OF THE MIGEATOKY MOVEMENT
AND WHAT GUIDES BIEDS DURING THEIR
MIGRATIONS.
HOUGH Herr Gatke has devoted separate chapters
to the discussion of these two features of the
phenomena of migration, they may be conveniently
examined together, for it will be found that one,
not unnaturally, throws light on the other.
At the outset it may be stated that in neither
case does he put forth any explanatory theories of
his own ; indeed, he frankly confesses his disinclination to even
enter upon such a hopeless task.
The following paragraphs are an attempt to embody the views
which have found most general acceptance as to the "cause of
the migratory movement," supplemented by a few suggestions on
the part of the writer.
The principal factor necessitating these long journeys on the
part of birds from their breeding grounds, to winter quarters in
distant lands, is undoubtedly lack of food ; cold of itself, would
probably not have sufficient direct influence on the majority of
species to induce them to leave the homes to which they seem so
devotedly attached. Nevertheless, the prime originating cause of
the habit was, undoubtedly, the setting in of rigorous conditions-
in what was probably their ancestral home, thus necessitating its
temporary abandonment. A low temperature of any duration
accompanied by a heavy fall of snow, means, to the great
majority of birds, the cutting off of all food supplies. Geological
evidence is pretty conclusive that at one time those regions in
the north which now endure the severities of an arctic winter,
previously enjoyed a fairly equable climate, perhaps akin to that of
our own islands at the present day. At the former period these
110
northern countries, no doubt, supported an abundant and resident
avian population. Opinions, however, differ as to the duration of
daylight which prevailed so far north during the winter months.
Some hold that simultaneous with a temperate climate there
existed a proportionate amount throughout the year. Others,
again, think that the duration of the latter was no greater than at
the present time. In the opinion of the late Henry Seebohm, the
Polar Basin was the ancestral home of the great family of the
Charadriidae, and the earliest members of this group performed
their first migration, not in search of food alone, but in quest
also of light.
It will not be necessary to speculate on the latter probability,
though this additional reason for migration should be by no
means ignored. It will be profitable, however, to examine the
daily lives of certain sedentary species of birds in our own
country at the present day, for it is not unreasonable to suppose
that their habits correspond to those formerly living in the Arctic
regions at the time the latter enjoyed a temperate climate. There
seems to have been innate at all times in birds, with the excep-
tion of a few species, a passionate love for particular localities,
not only in the selection of nesting sites, but also for familiar
winter haunts and roosting places. Professor Newton, in his
" Dictionary of Birds " recounts some interesting cases illustrating
this strength of attachment to the former. The most remarkable
instance to which he refers is, undoubtedly, the return of a pair
of Stone Curlews a bird of heaths and open countries to a
nesting site which had become the centre of a plantation. To
these favoured localities the same birds, or their offspring, return
year after year, either to nest or to spend the winter.
The early arrival in Great Britain of the Chiff- Chaff and
Wheatear is typical of this strong desire on their part, to return
to their breeding homes. The latter has on two occasions been
known to reach the south-west of England as early as February
(vide " Migration Eeports ") and the former regularly arrives by
the middle of March. Nidification in either case not commencing
until six weeks later. Further evidence to the same effect may
be gleaned from the movements of Skylarks, Starlings, &c., at
Heligoland (p. 5).
Ill
From these familiar haunts birds make those daily journeys
which fill up the stories of their lives. In the breeding season
material must be sought for and carried to the nest, next the
female must be fed as she broods, and eventually the young when
they are hatched. In the autumn and winter, when food is much
scarcer, those species like Curlews, Lapwings, Books, Daws,
Starlings, and many others, band themselves together into flocks,
setting out at particular times from the common roosting place on
their daily forays, which often extend for many miles, and to which
they return as regularly as the hour of sunset approaches. These
latter daily journeys are just as much migrations as are the great
movements of the present day. The difference is in degree not
in kind.
The writer recently experienced an amusing instance of this
clock-work regularity of life carried out by an old male Black-
bird. This individual was observed throughout a whole winter,
to pass at dusk with the utmost regularity a shelter, erected at
a duck marsh. This bird always flew down the same hedgerow
and in the same direction, and always at the same speed and
elevation. The following winter, apparently, the identical
Blackbird was observed to carry out the programme exactly as
before.
Such facts which might be multiplied, ad. lib., all point in
one direction, and form undoubted proof of the excellent
memory of locality possessed by birds.
It happens at times, however, on the advent of exceptional
cold, that these regular habits are disturbed, and daily migra-
tions in search of food have to be prolonged to such a distance,
that a return during daylight becomes an impossibility. Kesi-
dents in particular localities are therefore driven from their
customary haunts to other districts, usually on the outskirts of
the area affected by the frost. There they manage to exist until
a thaw enables them to satisfy their longing to return. All
species will not be affected in the same manner. Many like the
Buntings and Finches, draw near to the habitations of man,
where around stackyards, and the outskirts of villages and towns
they manage to maintain themselves until better conditions
prevail. In thickly populated countries, cultivation has had an
112
appreciable effect on migration, which should not be overlooked.
There can be no doubt that were it not for the latter, hundreds
of thousands of Finches and Larks would have to seek sus-
tenance elsewhere. In the same manner individuals of other
species, like the Hooded Crow, of which the great body regu-
larly migrate, are enabled to find an existence near villages,
even in high northern latitudes. Seebohm and Harvie Brown's
observations on the Snow Bunting in the Petchora Valley will
also illustrate the foregoing remarks (" Siberia in Europe").
It is only necessary to imagine the before- mentioned condi-
tions prevailing in Northern regions to see how the great migra-
tory movements of to-day have been developed, and how birds
have acquired that power or sense by means of which they are
able to unerringly find their way during the long journeys they
now accomplish.
As has been previously pointed out the movements of birds y
will, until the cold became very severe, have been confined to
those daily wanderings in search of food before described. But
as the spells of frost grew longer and more severe and their
extent affected a larger area, so will the distance to be traversed
have increased and the intermittent opportunities for return, or
attempts to return, to the familiar home have grown less frequent.
At the same time the attachment to the old haunts will not have
diminished, and on the other hand the power of finding their way
and the sense of locality will have constantly become more and
more acute owing to the new surroundings requiring their daily
exercise.
It now remains to be seen in what direction these early
migrations were likely to have trended. Whether we assume
that it was want of light or want of food which first induced
birds to temporarily forsake their original home is not of much
consequence. Both would be felt most severely in the north.
The general tendency, therefore, will be to wander in the
opposite direction. The effects of severe frost will be least
apparent along sea coasts, the shores of lakes and in river
valleys ; indeed at almost all times of the year food is found in
such localities in greatest abundance. It seems natural to
suppose, therefore, that those individuals and species which
113
followed the courses of the latter in their retreat before winter,
would have the best chance of maintaining themselves alive.
As the cold advanced from the north, birds will thus have early
acquired the habit of following coast lines trending to the south,
or some point approximating thereto, and those river valleys
whose course runs more or less in the same direction. It must
not be imagined, however, that without these guides, which
were, perhaps at most, merely guides to food, birds could
not have found their way, but that their presence in large
numbers in such localities is due as Herr Gatke himself points
out (p. 36) is the case at the present day to actual necessity.
But what was once a necessity has since become a habit. It
may be urged against this theory that the height at which
many species now conduct their flights, is strongly against the
probability of the assumption that birds ever followed the courses
of coast lines and rivers. It may be admitted that the latter
have now ceased to be followed as guides. It is even doubtful
if this were ever the case except unconsciously so, but there
can be little doubt that the old routes of migration are still
adhered to simply from force of inherited habit. It is highly
probable that the movement at its earliest inception and perhaps
for a vast number of years afterwards was carried out at low
elevations and in daylight, after the manner of those supple-
mentary migrations occurring late in the winter, or those short
peregrinations to which Herr Gatke alludes on p. 46. The
habit of migrating by night was most probably acquired at a
later date and may have arisen from the fact that the daily
breezes both in spring and autumn, except in the case of very
strong winds and gales, are apt to die down at sunset, the
hours of darkness being characterised by calm. It is a curious
fact that the Hooded Crow one of the regular day-fliers is
declared by Herr Gatke to be more indifferent to the state of the
weather than all other migrants.
So much has been said with regard to migrations over the
land. But the question arises By what means did birds first
acquire the habit of crossing wide seas to winter quarters, of
whose very existence we have no reasons for thinking they were
cognisant? The subject is fraught with the greatest difficulty
8
114
and various theories have been put forward in explanation, but
we may fairly assume that the pioneers of these latter movements
were only driven to undertake such a perilous flight under
pressure of urgent need. It seems highly probable that accident,
or at any rate meteorological conditions had a great influence on
the ultimate bourne at which these first flights arrived. No
doubt numbers perished, as they do even at the present day,
but still sufficient survived, who were impelled by the love of
their old haunts to retrace their steps when the conditions had
ameliorated. The theories of land-bridges, old coast lines, or
groups of islands, since submerged by geological changes, have
been put forward by certain ornithologists as explanatory theories
of the manner by which this habit of crossing wide seas has been
acquired. No doubt there is much to be said in their favour, and
that their influence on the path of migration is still traceable in
various localities at the present day.
Emigration, or the extension of the breeding range of species
has also had its influence on migration. Species have extended
in various directions, some from the south, others from the south-
east, or even east. Those from the south will have thus met the
cold in its advance, or followed it in its retreat, but the manner
in which they have acquired the habit of migration will not be
essentially dissimilar to that which has already been described.
Nevertheless, there are cases in which birds migrate from their
ancestral home in the south to breed in the north. According to
Seebohm the Swallows are an example of the latter phenomenon.
It now remains to add a few remarks on the evidence in
favour of the possession by birds of an acute sense of direction
and locality. It has been previously pointed out that so far from
enunciating any theory of his own as to " What guides birds
during their migrations," Herr Gatke frankly avows himself dis-
inclined even to undertake the task. The chapter in his work
he devotes to the question is, therefore, nothing but a statement
of his objections to the theories of others ; to only one of which
does he appear to give even partial adherence.
It is, perhaps, not to be wondered that he should feel dis-
inclined to put forth any theory of his own, committed as he
already is to the statements on the direction, altitude and
115
velocity of the migration flight as detailed in previous pages. No
theory that could be devised would be likely, in all its details, to fit
in with such various speculations, and he may well look upon the
task as hopeless.
In remarking on this wonderful power by means of which
birds find their way over such vast distances, his prefacing
words (p. 131) are not unopen to objection. He writes : " Man,
in spite of his senses and intellectual faculties, is not able to
continue moving in a straight line for even as much as a mile
in complete darkness or dense fog." A power of this description
varies greatly with individuals and even races, and the possession
of this sense of direction is very difficult of realisation by those
who are not so endowed. Complete darkness, moreover, is not a
condition of the atmosphere with which either man or birds are
familiar and there is abundant evidence to show, even in Herr
Gatke's book, that fog is just as puzzling to the latter as to the
former. It is an undoubted fact that in savage or nomadic man
this sense of direction, or power of orientation is highly developed.
Indeed, its possession is almost a necessity, for without compass
or other instruments, and with no knowledge of astronomy,
nomadic tribes have to undertake long journeys over desert and
trackless tundra in search of sustenance for themselves and their
domesticated animals. Man, of course, is in one respect at a
great advantage in comparison with birds, by reason of his ready
powers of intercourse with his fellow-men. A company of
savages will undoubtedly be more certain of eventually reaching
their destination than single individuals of the tribe. Naturally
the most experienced members of the company will be chosen as
pilots on these occasions. But here in the case of birds, a diffi-
culty arises, for it is undoubtedly a fact that it is the young, in the
great majority of species, which first set out from the breeding
grounds on the autumnal migration, and there is no reliable
evidence to prove that they are accompanied by older and more
experienced individuals as guides. Certain leading ornithologists,
however, have held the opposite view, and even so great an
authority as Seebohm states that the young are led by those
barren or otherwise non-breeding birds which are the avant
courier es of the migratory hosts (" Geog. Distribution Chara-
driidse ").
116
No one appears to have called attention to the fact that
whereas the hereditary desire to leave the breeding grounds in the
autumn appears to act with the greatest force in the case of the
young of the year, the desire to again return thither appears on
the contrary to be greatest in the oldest and most vigorous males.
If this assumption is correct we may reasonably suppose that the
hereditary impulse to leave the breeding grounds loses strength
as the individual grows older, whilst the desire to return thither
at the earliest possible date, on the other hand seems to gain
additional force. These considerations may even point to the
fact that it was the young which first set out on those daily
journeys in search of food before described, and may shed some
light on the theory that they feel the influence of the hereditary
desire to migrate earlier in the autumn than do their parents.
Herr Gatke points out that those migratory flights occurring
late in November and December are composed exclusively of fine
adult males of various species. No doubt, unless compelled by
the advent of exceptional cold, these old and robust individuals
would have remained on the outskirts of the frost until the
following spring. At the same time it must not be forgotten that
at one period winter in the north most probably set in much
earlier than it does at the present time.
It has already been pointed out that birds are possessed of
a very highly developed sense of locality or direction. It remains
to be shown how young birds, with the aid of this power, are
enabled without previous experience to migrate to winter quar-
ters which they have never before seen. The desire to migrate
is due, as has already been stated, to hereditary impulse to
leave the breeding grounds. The manner in which this
impulse has been acquired has also been described. To the
writer there is no difficulty in assuming that the possession of
the sense of locality and direction is also due to heredity. This
view gains additional force from the fact that this power of
orientation varies both in individuals and tribes, not only with
man but also and in the same degree with birds, both as regards
individuals and species. Amongst the latter it is those species
which are the most migratory who possess the sense in its highest
development, whilst those on the other hand who perform no
117
regular migrations, and have consequently no accustomed winter
quarters, are most erratic both in choice of the latter and of their
breeding grounds. The wanderings of the Bohemian Waxwing,
Rose-coloured Pastor, and the Common Crossbill may be pointed
out as well-known instances of these erratic habits. Why, there-
fore, should not the latter species be equally endowed with this
sense of locality and direction, unless it is because this faculty
has been acquired through slowly inherited experience.
Herr Gatke, however, objects to theories of this kind on the
grounds that the term unconscious inherited experience is nothing
but another name for instinct. He remarks: " Can experience be
something of which the subject is altogether unconscious ; and
further, can experience, the result of which is positive knowledge,
be actually inherited ? " To the writer he has here fallen into the
error of confusing inherited experience with experience gained
during life. Unconscious inherited experience is the sum total
of the latter acquired during the lives of many previous genera-
tions the experience of the race not of the individual. We see
all around us every development of the nest building instinct
from the lovely structure of the Long-tailed Tit to the simple
depression in the sand of the Oyster-catcher. The former species
by inherited experience unconscious why it does so selects
materials in building its nest which will harmonise with the
lichen-covered branches of trees, thus rendering the nest incon-
spicuous. Were it conscious of the reason for selecting such
material, however, it would hardly make the frequent blunder of
placing the nest, early in the spring, in some hedge-row, where
these very materials have exactly the opposite effect, the foliage
not being sufficiently advanced to afford the necessary conceal-
ment. There can be no doubt that the natural site for the nest
of this species, and indeed, which is most often selected, is the
fork of some lichen -covered tree.
That the instinct or hereditary impulse varies in strength, not
only in species but also in local clans of the same species, there
is abundant evidence to show. Many birds which are strictly
migratory in the north of Europe are sedentary in our own
country, and moreover, the latter on the advent of exceptionally
severe winters of long duration, perish in large numbers, appa-
118
rently from utter lack of this impulse to migrate. In the ex-
perience of the writer the Mistle Thrush is a bird whose resi-
dent numbers fluctuate considerably from this cause; other
species are no doubt affected quite as much. The colony of
Curlews in West Cumberland, which breed in the fells and
winter on the neighbouring coast, which ordinarily enjoys a very
mild climate, suffered severely in the arctic winter of 1894 and
1895. An examination of dead birds on the beach revealed more
of this species than of any other, and it proved to be correspond-
ingly scarce in the breeding grounds the following spring.
Many Redwings winter in England whose migratory instinct
seems to be quite evaporated by the time they have arrived here.
It is notorious how they suffer during severe weather, though
a short further flight would convey them to a place of safety.
Mr. Eagle Clarke recounts instances of several other species
whose migration instinct, though it carried them to the limits of
their customary flight yet failed to land them to a place of safety
in the exceptional winters of 1881-2-5-7 (vide Digest).
In localities, however, where severe winters though not the
rule, are by no means infrequent, the migratory instinct may be
encountered in still different degree. Herr Gatke in several places
alludes to late movements on the part of large numbers of Plovers,
Curlews, Sandpipers, Finches and Larks (p. 19). These latter
flights may have been termed supplementary migrations. The
individuals comprising them appear to hold the intention of
wintering in some locality not far from Heligoland, but on
the approach of severe weather are forced to make a further
move, thus illustrating the fact that though in ordinary winters
their migrations would have already come to an end, still, from
greater frequency with which severe weather recurs in these
localities the migratory instinct to undertake a further move has
not been lost but is simply remaining dormant for the time being.
Other hardy species again will illustrate the winter lives of
birds, existing at the time migration had its first inception. Herr
Gatke' s graphic description of bird life at Heligoland when the
Baltic becomes frozen very far south, and large masses of ice
collect about the mouth of the Elbe forms a most striking pic-
ture of the latter phase of the phenomena.
119
Enough has now been written on the varying degree of
strength in which the migrating instinct is present in local races
and species of birds. It may be here remarked that the term
hereditary instinct or hereditary impulse, has been objected to on
the grounds that it is merely a method of evading a difficulty or
expressing our ignorance of the means by which an animal or
bird is impelled to perform, or accomplishes certain actions.
Such terms, however, are a necessity, and the objection loses its
force when the instinct or impulse can be proved to exist with
different species in greatly varying degree. We can never expect
to understand the actual mechanism or process set in motion in
the brain, either in following out a thought or performing an
unconscious act. Possibly if we could communicate our difficulty
to a bird we might get a similar reply to that which Von Midden-
dorf who first promulgated the theory of a " sense of direction,"
received from the Samoyede, whom he questioned 011 this
point. " Well," answered the latter, after regarding him with
surprise, " how is it that the little arctic fox finds her way on the
great Tundra without ever going astray ? " This Samoyede,
though conscious of his own powers, was quite as much at a loss
to account for their possession or how they acted, as we ourselves
would be if called upon to explain the various mental processes
taking place in our own brains.
Beyond the bare statement that such is not the case, Herr
Gatke produces but little evidence in opposition to the theory that
migration is conducted at lower elevations during the hours of
darkness than is the case during bright clear daylight. Evidence
collected at lighthouses and light-ships, however, seems to point to
the truth of this assertion . In view of this fact it may be remarked
that there is some evidence in favour of the theory that sight
comes in as an additional aid to the sense by means of which
birds are enabled to find their way. We can hardly imagine a
" sense of direction or locality " to be so acute as to enable any
bird like a Wagtail or Flycatcher to set out from its winter
quarters and accomplish the whole journey without a halt, to
some familiar field or garden, containing the cowshed, or summer-
house, on the door-hinge of which it had been in the habit of con-
structing its nest. Of course in the case of young birds there can
120
be no such thing as landmarks, but with older individuals we can
imagine that while this sense of direction enables them to land on
a particular stretch of coast, perhaps at the mouth of a river,
whose course they follow, it is by power of memory, aided by
familiar landmarks, that they eventually reach the desired goal.
These latter portions of the flight are no doubt conducted in short
stages and during the hours of daylight. Travellers in northern
countries make little or no reference to migration by night, though
this is so great a feature of the movement in temperate regions.
The concluding portions of these journeys may thus traverse
very circuitous routes. Observations conducted by the writer in
a limited locality have proved beyond a doubt that certain species
reach their breeding grounds from a direction entirely opposite to
that which might have been expected, from our knowledge of the
general trend of the spring flight. Moreover, other species at
the same time cross this flight at an acute angle in travelling to
districts further removed.
It will not be uninteresting at this stage of the argument to
follow in imagination, the migratory flight of a flock of birds,
conducted in the normal manner, according to the theories of
Herr Gatke, from their breeding grounds in the north-east to
their winter quarters in the west or south-west of Europe. Let
us suppose that we are dealing with one of the " many hun-
dreds " which pass Heligoland on their journeys from "far
eastern Asia."
It is dusk and the time for departure has arrived. Without
more flocking together than has accidentally taken place during
feeding time, all the residents in a particular area set out from
their breeding grounds on a journey of two thousand miles or
more. No food has been taken for some hours, and the winds
being unfavourable near the surface of the earth, all rise to a
height of at least 20,000 feet, whence guided by some unknown
power, and at a speed of from 150 to 200 miles an hour, they set
out on their rushing and undeviating flight to the west of Europe.
Here, however, the direction of the latter must be altered and a
turn to the south executed in mid-air, which carries them, after a
further flight, to the neighbourhood of Heligoland, where again a
second turn is accomplished and the remainder of the journey is
121
performed in the old undeviating westerly direction, until dawn
finds them at their goal on the shores of England ; neither tired
nor hungry after their great exertions.
This programme may not be carried out in its entirety by all
species, but to the writer it forms a true sketch of migration
under normal conditions, according to the theories of the author.
Von Middendorff's theory of a " sense of direction " possessed
by birds, has already been discussed. There remains, of those
mentioned by Herr Gatke, that of Professor Palmen. The latter
ornithologist, after selecting certain well-known species, carefully
accquired all the information he could obtain from the notes of
travellers and local investigators relating to their progress across
the Eastern Hemisphere. He then mapped out what he considers
are the chief routes these particular species follow during their
journeys. In all cases the latter traverse sea coasts or great river
valleys, from which fact the Professor argues that these natural
routes are followed by migrants as guides to their destination. In
referring to this theory, Professor Newton, in his "Dictionary of
Birds," remarks : " One of the routes (X) [i.e. starting from
Greenland and Iceland, passes by the Faroes to the British
Islands and so joining the second (B) and third (C) runs down
the French Coast] , described by Professor Palmen, and one of
considerable interest to dwellers in the United Kingdom, is
extremely questionable. Indeed, the data to establish its
existence were not forthcoming when he wrote, and probably
are not forthcoming now, though in the interim much has been
done toward the collection of facts at light-houses and light-ships
around our coasts by the * Migration Committee ' appointed by
the British Association in 1880." It is, therefore, very interesting
to find that Mr. Eagle Clarke, who approached the subject without
any preconceived theories or bias, confirms Professor Palmen's
statement, in his digest of the information collected by the above
Committee.
Herr Gatke, however, does not even enter into a detailed
criticism of these theoretical routes. In alluding to them he
remarks : " Observations in nature on the author's own part
appear not to have been made the basis for this work," which is
as much as to say, that observations, unless personally con-
ducted, are not of sufficient reliability on which to establish a
theory. He also considers that he has sufficiently explained his
views on the direction of the migratory flight in a previous
chapter, and that any closer examination of Professor Palmen's
arguments is therefore unnecessary.
When refuting the theories of other ornithologists, Herr
Gatke is apt to bring forward those enunciated by himself, as
though the latter were equivalent to undeniable facts. However
satisfactory they may appear to himself, it would have been
better to have awaited their general acceptance before adopting
so arbitrary a method of argument. The allusion to his own
assertion on p. 140 that it is quite within the power of a bird to
cross unaided the entire Atlantic from Newfoundland to Iceland
in nine hours, and the frequent references to his own estimates
of the speed attained by the Carrion Crow and Bluethroat, are
cases in point.
No theory that has yet been brought forward will, perhaps,
account for the means by which every individual species, which
may perform an exceptional migration, now finds its w r ay. In
objecting to the statement that many birds at the present day
conduct their flights over the sea, where at one time there
existed groups of islands, or perhaps peninsulars, forming so-
called land-bridges, Herr Gatke refers to the case of the Virginian
Golden Plover, which species, according to his own views,
migrates in one unbroken flight from Labrador to Brazil. Along
the whole course of this journey there are no traces that any
such land-bridges ever existed. Setting aside the fact that neither
has the identity of the flocks passing the Bermudas with the
Labrador birds been proved, nor has the exact point at which
the latter leave the mainland been ascertained ; it does not
seem to have occurred to him that this long flight is the out-
come of a series of migrations gradually increasing in distance.
Apparently, he seems to think that conditions suddenly arose in
Labrador necessitating a flight from thence to Brazil, without
any intervening development.
It seems far more reasonable to suppose, however, that this
flight has gradually grown from short intermittent journeys along
the Atlantic coast, which gradually increased in extent as the
123
conditions necessitating its commencement extended their area.
How those individuals first commenced to fly over the sea it is
impossible to say. Before the migratory habit was initiated they
can have had no knowledge of Brazil. Perhaps the general
direction of the winds which are westerly at the present day and
may have been so at that period, had their influence on these
early flights. In the meantime, inheritance will have had ample
time to accomplish its work, and the accumulated experiences of
thousands of generations will have sufficiently developed the sense
of locality by means of which these flights are able to find their
way over the pathless tracts of the Atlantic at the present time.
Herr Gatke in several places in his work compares the so-
called migrations but properly speaking emigrations, of insects
with those of birds, bringing forward the case of the former as an
objection to the theory that the sense by means of which birds
find their way has been acquired and transmitted through
inherited experience.
To the writer the migrations of insects are of quite a different
nature to those of birds. In the first place they are of most
irregular occurrence, and are declared by the author himself to be
due to the prevalence of certain meteorological conditions. The
only bird migrations which they at all resemble are those of
Pallas' Sand Grouse, which latter are emigrations in the true
sense of the word. It is generally assumed that this species has
always followed the same course during its irregular move-
ments, but to the writer it seems very probable that other flights
may have emigrated to quarters in opposite directions. In the
second place the insects composing these flights never return to
the place of their departure and it is not known for certain that
they ever land on a coast at any distance away.
In the third place it is very doubtful if an insect like Plusia
gamma, to which Herr Gatke specially refers, has the power of
crossing the North Sea ; its speed of flight being no greater than
that accomplished by an entomologist intent on its capture, as the
writer knows from experience. The simultaneous appearance in
Lincolnshire of this species in great abundance, with the advent
of large flights at Heligoland, has no significance whatever. This
abundance is by no means confined to the former county and has
124
been equally marked all over England. As an instance of the
profusion in which this insect has occurred in the Midland coun-
ties, it may be stated that the writer took upwards of thirty pupae
of it from a carrot bed only a few feet in extent and after a very
superficial search. The imagoes emerging from all of them within
a few days of one another.
We know, however, far too little of the lives of insects to
draw any conclusions from their emigrations. But the absence
of many species from England which are common on the conti-
nent in localities at its nearest points to the latter is significant,
and points to the fact that migration in bulk rarely, if ever, takes
place.
There is another well known species of insect which has
occurred in great profusion throughout England at irregular
and usually widely separated periods, viz., the clouded Yellow
Butterfly (Colias edusa).
In the year 1876 a few occurred in certain localities in the
Midlands, as well as in other parts, late in the summer ; but in
the following year, 1877, the species simply swarmed. Now of
the very numerous examples captured by the writer and his
friends, not one exhibited any signs of having undertaken a long
journey. All on the contrary had the appearance of having
newly emerged from the chrysalis. There can, therefore, be no
question that the larvae had been hatched locally and that the
great abundance of the species was due to the prevalence of
certain favourable conditions of the nature of which we are quite
ignorant.
The abundance of Plusia gamma, which, however, is at all
times a common insect, may, no doubt, be attributed to a similar
cause.
Of the other species mentioned by Herr Gatke, certain of them
are such feeble and lethargic flyers that a journey to any distance
beyond the island is simply an impossibility.
It will be noted that on one occasion, viz., August 19th, 1882,
a strong migration of birds took place accompanied by thousands
of Plusia gamma. " A thunderstorm with high winds, subse-
quently put an end to the migration " and no doubt put an end
to the individuals comprising the flights of Plusia gamma at the
same time.
125
To the writer these migrations of insects partake more of
the nature of a stampede of animals, but unlike the latter probably
arise from some more natural cause, but for all this the direction
followed may be just as erratic. It is an interesting fact, how-
ever, that during the prevalence of east winds Noctuse fail to be
attracted by the sweets provided as a lure by the entomologist on
a " sugaring" expedition. Indeed, in this country, during such
conditions, insect life is not much in evidence.
In his opening remarks on the " cause of the migratory
movement," Herr Gatke notes, that "it would be interesting to
discover what induces birds wintering in the more southern
parts of Africa, where they are subjected to hardly any changes
of climate, suddenly to leave these stations for their breeding
homes in the north; or again, what it is that urges the in-
dividuals of a species, the nesting stations of which are situated
say, in central Germany, to start on their journey a month
earlier than other members of the same species, the breeding
homes of which are in Northern Scandinavia, and which have
been passing their winter in North Africa. The later allow the
migrant stream of their more southern kinsmen to pass over
them unmoved, as though they were fully conscious that their
own time for departure is not yet ripe and that their breeding
quarters are still held bound in the depths of winter."
It may be questioned whether it is possible to prove that any
species breeding in Central Germany migrates to the southern
parts of Africa to winter there. The general opinion on this
point is, that the local race of a species breeding in the former
country, would more probably winter in Northern Africa, and
that it is the more northern races which winter further south.
" The higher a bird breeds in the north, the further south it
migrates to winter " has become almost an axiom. But apart
from these considerations, the explanation of the above pheno-
menon probably lies in the fact of the earlier activity of the
breeding organs which recurs at this period of the year coupled
with the innate tendency to return to their original homes at the
same period, which must set in in the case of the individuals
migrating to breed in Germany some weeks before it takes
place with those breeding in the north. The fact that non-breed-
126
ing birds are the last to start on their migrations lends additional
evidence in favour of this probability. We are driven to an
explanation of this kind in preference to admitting that birds
wintering a thousand or fifteen hundred miles away are conscious
that their breeding grounds are fit or unfit for occupation.
However, the foregoing theory will not suffice in the case of the
autumn flight. It is undoubtedly a fact that this movement
commences with one or two species, a few weeks at most, after
the close of the breeding season. The early migration of the
young of the Starling is a well known case in point. In this
particular instance the explanation of this early migration on
the part of the young may perhaps be attributable to a diminish-
ing supply of food. The latter fact may arise from a simple
cause, i.e., the drying up of the countries inhabited, with the
consequent disappearance of worms and slugs on which the young
feed, owing to the summer heat, and the growing scarcity of larvae,
which at this period of the year will be undergoing their meta-
morphoses under ground, preparatory to their emergence as
imagoes in the autumn. It is interesting to note that in our more
pluvial climate, the young of this species do not migrate like
their relations on the continent. However, we know so little
of the former extension of the breeding ranges of any species,
so that such explanations must always remain more or less
conjectural. If we knew that the Starling at one time bred in
the high north, it would be within the bounds of possibility that
the early migration of the young was the survival of a former
necessary habit. It has already been pointed out that the
duration of winters in these latitudes has been subjected to
great variation.
Herr Gatke further objects to the theory that migration
from the north is altogether due to a lack of food. He remarks :
" This explanation would have much to commend it if all the
individuals of a species left their breeding places in the highest
northern latitudes simultaneously, and if all followed a north
to south line of migration. I have, however, shown myself,
firstly that the young and old birds of a species migrate a
widely different times ; and secondly, that a number of species
perform their migrations on an east-to-west line of flight." The
127
explanations accounting for the first mentioned fact have already
been discussed, and whether we accept the theory of an east-to-
west line of flight or not, matters very little, as it is undoubtedly
the case that the winters in Western Europe are milder than
those in the east. Moreover there is absolutely no evidence to
prove that the old birds set out so very long after their progeny ;
indeed, observations all tend to prove that the latter migrate
slowly at first and in short stages, and that in many cases it is
only the actual advent of wintry conditions that brings about
those rapid torrents of migration alluded to by Herr Gatke on
p. 146. Whether birds fly by daylight or in darkness has no
bearing whatever on this point, and while there may be no
temptation to break the flight at an inhospitable little island, the
reverse is probably the case on encountering more favourable
localities.
Herr Gatke concludes his chapter on " What Guides Birds
during their Migration," with a reference to the rare occurrence
of a migration which may be described as not only retarded, but
actually turned back, through meeting with wintry conditions in
the land towards which it was travelling. In his view this
occurrence was similar to that experienced by Seebohm in the
valley of the Yenesay, when the latter was awaiting the break
up of winter on the arctic circle. Another interpretation of the
phenomena, however, as regards this particular instance may be
put forward. Mention has frequently been made of those supple-
mentary migrations which so frequently take place at Heligoland
late in the winter. Birds suddenly appear travelling past the
island in large numbers, their presence at these times being said
to unfailingly indicate the proximity of severe weather. We are
unfortunately told but little of this interesting incident beyond
the fact that on becoming aware of the strong migration in pro-
gress, the author came to the conclusion that the spring move-
ment had set in with remarkable force and at an earlier period than
usual. On becoming aware, however, of the direction in which
the birds were travelling, after considerable reflection, he came to
the conclusion that the flocks comprising the flight had already
once passed the island, and were now compelled by the severe
weather encountered ahead to retrace their steps. May it not
128
have been the case, however, that owing to the previous mild
weather these birds had wintered in some quarter close at hand,
with no intention of migrating any further, unless compelled
by severe weather ? The circumstance is alluded to here on
account of the suggestion on the part of Herr Gatke that these
flocks had apparently hit upon the right way of escaping from a
difficulty.
129
EXCEPTIONAL MIGRATION PHENOMENA.
N the present chapter Herr Gatke endeavours to prove
that the occurrence in Heligoland or other localities
of individuals, of species, whose normal ranges do
not extend so far by hundreds, and in some cases
thousands of miles, is due not to accident, but to a
voluntary and conscious intention on the part of
these wanderers, and that this voluntary act is in its turn the
result of recurring causes, or in other words, is governed by
certain laws which have been previously overlooked. It will be
interesting, therefore, to follow him in his explanation of these
laws.
In rejecting the formerly accepted opinion that the occurrence
of these casual visitors has no scientific value whatever, the
remarks : " This was the outcome of the traditional error, accord-
ing to which these strangers were, as a rule, simple and inex-
perienced young autumn birds which had either been driven out
of their normal course by storms, or were wandering about the
world at haphazard" (p. 114). The latter statement seems to
be stretching a point. Few naturalists ever imagined that any
bird, young or old, wanders about the world at haphazard. In
disproof of the statement that this straying from the customary
track is most frequent on the part of young birds, Herr Gatke
first brings forward the evidence of those species whose breeding
ranges lie some hundred of miles to the south east of Heligoland.
In alluding to the latter he calls attention to the fact that twelve
old against two young summer birds of the Black-headed Bunting
(Emberiza melanocephala) have been obtained, and in the case
of the Eastern Pied Chat (Sax. morio), the Black-eared Chat
(S. aurita), and the Desert Chat (S. deserti), two old examples of
9
130
each species as against one young bird of the last-named only.
Again, almost all the examples of the Rose-coloured Starling
which have occurred are old birds, and so on.
Considering the relative situations of the breeding grounds
and winter quarters of these species, this is just what might have
been expected. The general direction of their migratory flight
in spring being south-east to north-west, and, of course, the
reverse in autumn, how could it be expected under these cir-
cumstances, that young birds should migrate in an exactly oppo-
site direction to their parents ? The improbability of the latter
fact seems to have occurred to Herr Gatke, for, writing on the
Short-toed lark (p. 357), he remarks : " In the absence of any
single actual instance in support of it, the idea of an autumn
migration directed to the north-west from Greece or Asia Minor
cannot be entertained." He further adds in alluding to these
exceptional visitors : "No more do the conditions under which
such migrants make their appearance admit of the conclusion
that these movements are merely of a roving or blundering kind,
without definite plan or aim." It is difficult, however, to see to
what else but blundering we are to attribute the presence of the
few young birds of these south-eastern species, which have been
captured so far from the home in which they were reared. It is
simply impossible to prove an intention on their part to under-
take a journey in an exactly opposite direction to that of the vast
majority of their fellow-travellers. Why should it be assumed
from the fact of eastern and north-eastern species occurring in
autumn and those from the south and south-east in spring, that
these casual visits are dependent on definite laws or causes of a
recurring kind. The very lines of flight are sufficient explana-
tions in themselves. It would, of course, be absurd to expect
the appearance of young from the latter quarter in spring, or in
other words, before they are hatched.
In the idea of Prof. Newton, if we grant the existence of laws
determining the flight of every winged vagabond they must be
very different from those which are obeyed by birds commonly
called migratory. The former laws would seem to be controlled
by purely external circumstances, and while we may predict with
a reasonable degree of certainty the occurrence of a certain
131
number of stragglers from North America or Asia within a given
number of years we cannot say to a year when any particular
example will arrive. In a given period it might be safely pre-
dicted that there will be a certain number of accidents in the
streets of London or any large town, some of which may be said
to be governed by causes of a recurring kind, such as the pre-
valence of fogs and gales. Nevertheless, we still look upon these
casualties as accidents, not as the result of definite laws. It
should not be forgotten that the list of waifs and strays on
Heligoland is the result of more than fifty years of observation in
a locality " where literally not a bird escapes notice." Under
the circumstances, though the list is certainly a remarkable one,
Herr Gatke seems to attach far too great an importance to the
evidence it presents.
He attributes the presence of these south-eastern species on
Heligoland to a most curious cause, i.e., the death of one of
a pair during the period of incubation. After an accident of
this kind the surviving parties, to satisfy the persistent impulse
towards accomplishing the act of propagation, commences the
migratory journey anew ! ! ! Such a theory is quite opposed to
all experience. Probably in no locality are the sexes of birds so
evenly balanced that each individual finds a mate. In some
species the males undoubtedly predominate. Under these cir-
cumstances it would be remarkable, if it were necessary, for the
female to undertake a fresh journey in quest of a new partner.
On the contrary, it is well known that on the death of either male
or female the survivor finds a new mate without any difficulty,
and over and over again it has been remarked with what wonder-
ful celerity this takes place. To take the case of the Black-
headed Bunting. Herr Gatke mentions that with the exception of
the young bird of the year which was shot in August, all the
examples procured occurred between May 6th and June 18th,
i.e., from the commencement and during the height of the breed-
ing season ; and, moreover, of these, five were old males, three old
females, and lastly, a male in its second year. A further old pair
were added to his collection by Mr. J. H. Gurney; these facts
thus show that females occur nearly as frequently as males.
It may be pointed out here that several common species, such
132
as the Fieldfare, Blackbird, and Kedbreast, have been met with in
the lonely island of Jan Mayen. It seems absurd to suggest that
these individuals migrated thither on account of losing their
partners in some more southern clime.
It is very difficult to follow Herr Gatke in this theory. He
appears to consider that in the spring the impulse to migrate, and
the desire for propagation are identical. No doubt the state of
the breeding organs at this period has considerable influence in
causing the departure of birds from their winter quarters. But
when once the breeding grounds are reached and pairing has taken
place, it is difficult to see how their condition can re-kindle in
either survivor of a pair an impulse to travel many hundreds of
miles beyond their proper quarters in search of a fresh mate when
there must be opportunities to satisfy this desire near at hand.
If we turn to the author's facts relating to the south of
England and examine them in the light of this theory, we shall
find still more remarkable evidence. Eeferring to the Bee-eater,
we find it stated (p. 121), that twenty examples were seen in one
day in Norfolk, and twelve were shot within the same period of
time at Helston, in Cornwall. We must, therefore, assume that
twenty individuals in the first case and twelve in the latter,
living in the same localities, had respectively lost their mates at
an identical period, and had started together on their migratory
flight afresh in search of new partners. We must also assume
that the victims were either all males or all females, otherwise we
should have expected the survivors to have paired among them-
selves. We, however, know that both sexes are represented
amongst the individuals of this species which reach our southern
counties. Moreover, the Bee -eater breeds freely in south-eastern
Europe and winters in north-western India. Therefore, under
the same circumstances, the species should visit Heligoland pretty
frequently like the Black-headed Bunting. The reverse, however,
is the case.
It will not be uninteresting to examine the geographical
ranges of the species said to reach Heligoland from regions lying
to the south-east of the island.
Eleonora Falcon. The Heligoland example of this Falcon
was seen by Aeuckens, but not obtained. The species was after-
133
wards identified from a skin. It is found in Spain, Sardinia,
Greece and Syria. It also occurs in Northern Africa (Bree.).
Lesser Kestrel. " The homes of this small Falcon extend
through the whole of Southern Europe " (Gatke, p. 176). "In
the Spanish Peninsula it is very numerous" (Saunders). This
species has occurred several times in the British Islands.
Hose-coloured Starling. This may fairly be called a south-
eastern species. Though in the year 1875 it bred in large
numbers in Italy. From the fact of the flocks following flights
of locusts this is a most erratic bird. It has occurred very
frequently in the United Kingdom, and in many parts of Europe.
Apparently Herr Gatke finds a difficulty in accounting for
the presence of this species on Heligoland in August and his
explanation is rather far fetched. The majority of the individuals
captured there have been taken in June. These he would
account for on the theory that they are the survivors of pairs who
have lost their mates. It will be noted, however, it was not
until the 17th of the labter month that the first eggs were laid,
when the species bred so numerously in Italy (Saunders). With
regard to the examples obtained later in the summer, no less
than eight having been killed in August, 1853, and again three
young in grey early plumage in September, 1860, it is suggested
that the species may breed in European and Asiatic Eussia as far
north as the latitude of Heligoland, and that the young forsake
their normal course of flight and turn to the west on their
autumn migration. Or again, the possibility is suggested that
they are individuals which have been bred in Scotland and when
captured on Heligoland are on their way home to their usual
winter quarters. Any theory seems, to the author, more prefer-
able than the simple fact that they are individuals entirely out of
their reckoning. It is not unreasonable to assume that an erratic
species like the present may be less acute in its powers of orien-
tation than species which regularly frequent the same breeding
grounds.
Ehrenberg's Redstart. A single example of this species
obtained June 12th, 1864 an old male. It is found in Asia
Minor.
Rufous Warbler. Herr Gatke does not devote a chapter to
134
this species. We may infer that only a single individual has
been taken. It has occurred several times in the south of Eng-
land. Twice in September and once in October. In Southern
Portugal and Spain it is abundant (Saunders).
Orphean Warbler. Two recorded as captured many years
ago on the authority of Eeymers. One met with by Herr Gatke,
July 8th, 1876. This species has occurred in Great Britain. It
breeds sparingly in France. In Portugal and Spain it is abun-
dant wherever the olive grows. It visits Savoy in summer, is
local on the mainland of Italy, and very rare in the islands ;
passes annually up the valley of the Ehone to the Vosges. The
vicinity of Metz and Luxembourg ; and straggles to Belgium and
to Heligoland, east of which it is unknown. ... it occurs
regularly in Dalmatia, Greece, Northern Eussia, &c., &c.
(Saunders).
Olivaceous Warbler. Frequents South Eastern Europe in
summer, wintering in Northern Africa. A single example
obtained September 20th, 1883. Herr Gatke remarks, p. 303,
"we may probably assume that the individual in question had
been roving about ever since June in northern and north western
areas " !
Olive-tree Warbler. Breeds in South-Eastern Europe alscf. {
Eastern Spain. Winters in Northern Africa. A single example
killed on the island in 1860.
Paddy-field Warbler. An uncommon species in Eastern
Europe. A single example captured June 12th, 1864.
Black-eared Chat. Breeds throughout Southern Europe, &c.,
&c. Two examples obtained, one May 12th, 1860, the other
October 26th, 1851.
Russet Chat. Breeding range extends from Portugal and
North West Africa to Greece. A chat, said to be identical with
this species, killed about 1840.
Desert Chat. Breeding range extends from Algeria, through
Egypt, Arabia, Palestine, &c. Herr Gatke remarks : " This
native of the hot and barren desert has on three occasions
emigrated from its southern home to Heligoland in the far
north." An old male shot, October 4th, 1856; a female caught,
October 26th, 1857 ; a fine old male shot, June 23rd, 1880.
135
Commenting on the fact that on November 26th, following,
an old bird was shot near Stirling, Herr Gatke writes : " There
can hardly be any doubt that both the latter examples left their
home at the same time and from similar motives, and that while
following the direction of their spring migration, the one got no
further than Heligoland, while the other by a less perilous route,
got so much further to the north west."
The butterfly, Papilio podalirius, was observed on the same
day as the first named example, viz., June 23rd, 1880. " It too
we are told had probably been led beyond the limits of its home
and across the sea by the fine warm weather, and light south-
easterly and easterly winds." From this passage it appears,
it was these winds which induced the two Desert Chats to
perform their abnormal migration, not the loss of their mates.
Eastern Pied Chat. A south-eastern species. One killed
May 9th, 1867 ; a second, June 6th, 1882.
Calandra Lark. Breeds throughout all the countries border-
ing the Mediterranean. An example said to have been shot by
Beymers, June, 1839 or 1840.
Black Lark. A winter visitant to Southern Eussia, breeding
in Central Asia. A female, shot April 27th, 1874 ; a fine old
male subsequently shot, July 27th, 1892.
Pallas' Short-toed Lark. A resident in Southern Russia.
One shot May 26, 1879.
Short- toed Lark. Breeds throughout the countries bordering
the Mediterranean. About thirty examples killed, partly in
spring and partly in autumn. The former examples on account
of their more ferruginous colour, compared with those which
have been shot in October and November, are said to un-
doubtedly have been derived from Greece and Asia Minor.
Herr Gatke remarks : " The home of the latter in Asia
must extend to the latitude of Heligoland, and the birds there
undoubtedly joining themselves to the many other species from
the far east, whose autumn migration proceeds in a westerly
direction. In the absence of one single actual instance in sup-
port of it, the idea of an autumn migration directed to the
north west from Greece or Asia Minor cannot be entertained" ! ! !
Why not here more reasonably suggest that these autumn
136
examples had been roving about as in the case of the Olivaceous
Warbler and were captured on their return migration.
Black-headed Bunting. This species has already been com-
mented upon.
Girl Bunting. It is remarkable to find this species included
in the list of casual visitors from the south-east as we read
(p. 371). " The bird, however, is a pre-eminently western species
. and in fact affords another proof of the rare occur-
rences of western and southern species in Heligoland." An
example killed April 22nd, 1862, and a second March 31st, 1883.
Red-headed Bunting. An eastern species. Two old males
obtained. First on June 20, 1860. Second some years later in
the month of September.
Meadow Bunting. Eesident in Southern Europe and Northern
Africa. An authentic example killed March 8th, 1882, an old
male. An individual shot at this early date can hardly have lost
its partner.
Cretschmar' s Bunting. A summer visitor to South Eastern
Europe occasionally occurring as far west as France. "About
a dozen examples, for the most part fine males, obtained between
May, 1848 and 1867. In the course of the last twenty years,
however, it has been observed and shot on one occasion only." In
accounting for the latter fact, two explanations occur in the light
of Herr Gatke's theories. First, this species has latterly enjoyed
a remarkable immunity from casualties during the breeding
season ; or secondly, as he suggests himself, the absence now of
warm and fine weather in the early summer.
Large-billed Reed Bunting. A resident in South Eastern
Eussia. One caught April 24th, 1879, others possibly seen. It
is difficult to think that this individual had already lost its mate
so early in the year. The species, moreover, is said to be a
resident in its European breeding grounds.
As has been pointed out, the presence of these so-called south-
eastern species on Heligoland is in one place attributed to the death
of one of a pair of breeding birds, causing the survivor to take up
the migratory flight anew, in search of a fresh mate. It is, there-
fore, interesting to read on p. 10 that, " occurrences of this kind,
i.e.', south-eastern species, are conditioned by the co-operation of
137
so many meteorological factors, that completely successful results
in this direction are extremely rare."
Marsh Sandpiper. Breeds from Hungary eastwards. A single
example obtained May 7th, 1862 ; an early date for this species
to have lost its partner.
Black-winged Stilt. Breeds throughout Southern Europe ;
said to have been formerly well known to Heligolanders, an
example seen June 25th, 1879, by Jan Aeuckens.
From the above list it will be seen that the majority of these
so-called south-eastern species have occurred on Heligoland only
once in fifty years. Further, that so far from being confined to
the south east, many, on' the contrary, breed both in Northern
Africa and throughout the countries bordering the Mediterranean
in Europe. Some are again resident species and others have
occurred at such early dates as to throw great doubt on the
supposition that they have taken up the migratory flight anew
owing to the loss of their nesting partners. Under the circum-
stances it seems idle to attempt to prove that these irregular
occurrences are due to the influence of definite laws. It is far
more reasonable to suppose the majority have simply over-shot
the mark in their eagerness to reach their breeding grounds. No
doubt the sense of direction, or whatever we like to call the
means by which migrants find their way, varies greatly in
individuals and in odd cases is altogether deficient. Or, again,
single individuals may frequently attach themselves to migratory
flocks of other species wintering in the same locality but travelling
to different breeding grounds, and so get carried out of their
proper track. The most recent capture of the Pine Grosbeak
in England occurred in the Midlands during an unusually strong
migration of Fieldfares, a flock of which it had, no doubt, joined,
though properly speaking it is not a true migrant. Strong
winds also, at times, exert a certain influence on the appearance
of these erratic wanderers.
In the light of the foregoing evidence, it will hardly be worth
while to discuss the cases of species from Northern Africa or
Western Europe, which have occurred on Heligoland. According
to Herr Gatke, birds in the latter locality have a great disinclina-
tion to migrate to the east. It is difficult to say to what species
10
138
he refers, however, as there are remarkably few peculiar to this
part of the continent.
Without going into a list of American species occurring in
Great Britain and Heligoland, a few remarks may be made on
the probable manner and route by which they reach their
respective localities.
From the fact of migrants in narrow seas settling so frequently
on the rigging of ships there can be no doubt that many a bird is
saved from drowning by this temporary aid, and it is only reason-
able to suppose that the presence of, certain of the smaller Ameri-
can species in Europe has been greatly aided in this manner.
Herr Gatke's objection has little weight that the time taken up
in resting only adds to the period during which these individuals
must go without food. This fact is evident, but still, as he tells
us himself, birds migrate on empty stomachs, and on reaching
Heligoland, so little are they affected by their efforts, that a stay
of only a few hours is sufficient to fully recuperate their powers.
A rest, therefore, seems of more value during these long flights
than food.
It is a curious fact and one that should be by DO means lost
sight of, that the American birds captured in Europe or observed
out at sea, have been in nearly all cases single individuals ; very
rarely flocks. In the face of this it can hardly be doubted that
the majority of the smaller species have been brought over in
cages and have escaped on nearing or on arrival at land.
Of the larger species, which have occurred in Europe, such
as the American Bittern and the various waders, the greater
number breed in the far north and no doubt are often carried
beyond their proper nesting stations by various influences. The
further north they go, the more chance any slight deviation to
the east will be likely to convey them to Europe on their return
journey. It must not be forgotten too, that as far as we know,
there is nothing to prevent these northern breeding species from
flying completely across the poles to the breeding grounds of
other species which regularly pass our shores on migration.
When we reflect how many birds have been observed to stray
to great distances beyond their proper quarters the capture
of the Hoopoe in Spitz-Bergen may be cited as an instance of the
latter fact the probability of this assumption becomes apparent.
139
By what precise route these American species reach our
shores it is impossible to say, but from the fact that the majority
have been obtained on our eastern and southern coasts it is
most probable that they have travelled down the shores of
Norway and then crossed the North Sea, in company with our
customary visitors; or they may, as Professor Newton points
out, have actually crossed the Atlantic with the aid of a strong
westerly gale. However, Herr Gatke will not admit the assist-
ance of the latter agency #s at all necessary. The voyage across
the Atlantic according to his theory is undertaken as a voluntary
act, for he writes that the objection on the part of birds to
migrate east in the autumn ; which according to his view is
apparent in Western Europe, ceases as soon as we cross the
Atlantic. Yet after discussing the question of the route by
which American species reach Heligoland, which he thinks there
can be no doubt is accomplished by first crossing the Atlantic
and afterwards the British Isles or France, he is ready to assert
in support of his favourite theory of an east to west flight, that
the example of Turdus Swainsoni, captured October 2nd, 1869,
" no doubt reached this island by an east to west route of
migration" (p. 116). The latter individual is thus required to
traverse the Pacific and the whole of the continents of Asia
and Europe.
With reference to another species, i.e., Tringa maculata to
which Herr Gatke draws attention, pointing to the fact that nine-
teen instances of its occurrence in England have been recorded,
it may be remarked that in the opinion of Mr. J. H. Gurney,
who has been at considerable pains in investigating each case,
very few are open to credence, mistaken identity being probable
in most instances.
In objecting to the theory that birds may be blown across the
Atlantic by westerly gales, Herr Gatke alludes to the fact that
the Virginian Golden Plover is of the rarest occurrence in Europe,
contrary to what might be expected from the fact of its migrating
across the ocean in large numbers via the Bermudas to Brazil.
It is quite possible, however, that this Plover, from its close
resemblance to the Golden Plover, may be overlooked. Only an
ornithologist would detect the difference, and, moreover, he
140
forgets that he has himself called especial attention to thi
that this species is one of the most powerful fliers knowi
bird which can maintain a speed of over 200 miles an hour
long period, would hardly be likely to be blown very far out
course by the most violent of gales. Two other species,
Sabinii and Rossi are included in his American list of Helij
captures, though so little is known of their breeding groi
Eecently, however, Nansen has met with the latter in
numbers in Franz Joseph Land, thus rendering it improbable 1
the Heligoland example may have come from America at all.
In the light of the evidence discussed in the present and f(
going chapters, it seems very hazardous to assert the opin!
that the migrations or wanderings of any species are strid
confined to a rigidly mapped out route. Probably every b|
goes its own way. Those huge assemblages which pass pal
cular points result from the fact that the path of many in reaj
ing certain localities is for a long distance identical.
species, nay every little clan of birds has its own migrat*'
history, resembling as a whole the story of the common
but on the other hand differing at many points in its mil
details. So far from being characterised by a flight in two
directions, the route followed will be partially governed by t
relative positions of breeding grounds and winter quarters, aj
the time honoured paths by which the traveUing hosts have
unknown ages passed from one to the other. Even in the li
of Herr Gatke's theories the simple east to west autumnal fli
has at some point to be supplemented by a turn to the south
south-west, and again the course of the north and south joui
in the countries lying towards the head of the Mediterfai
Sea, gives way to a flight from north-west to south-east.
