coset baitiekctete is ae scouataete Se a eiaeas 4 Shak etree 4 § rH sia sii ssf ai Met 4 “ , > . ci ii vu eb uroes ot eenbenast i _ weal : ‘ hv Miedrts), * at Ve basbee celts. ie ‘i we inde Mie “ Faiainiets SeF4 904s Fsadeid dono teh sealant an Sass hadelatl Se ledes 3 tare * ae hate she ie oteaeh ete a ed ss) edeotens es . 1 os 7 merase hs % WHI e fe ce iat sacha Nast Nahe eet “4 ot» wi pt ela? gns area hassapened de He aja te tH ee didshade Bele Lao bits leh 7 ecient thas pag aie of Mee! ey hh ieee ae Peseta oe) Me m be iveleibeaie tee ‘ HHL didn't je ton seas yee peti prea FY Patt bs ste} ds sage eden ; ; Ish oleae, Prirtr Peltserics, ‘ * sbisctdsagee Saaee aie Seer istt theory eseset seer sinha rH M4 hos aed vee os i . reed Ridebabiadls Siraotertairities saan 7 bal 39 Ving bed isin . ha emg ite { Sead ro age ent aan , . i Wi Mesnensens, ihe sits) rant aah init oe dee Somattt " certs bakd : te as Wy vb Ca SS ery fai ea is iS iiss . (P i ede heted the wv verre. Vee ay U Wei ng we tee TT EE TL Ld tbe be Ae Dt Ti}. *N TF fam, vip? Fi a a enw o Sieeeeeeee re ewes ytyrye wert | Ww TT MMA \ . i>. ie j a! al eS Se eo 2 www ‘ tte Tad iS “= Wry try on eweetS weuewp eU wry Ww | ‘ore x hs ge a@ ¥ _ wwe a ¥ 1 vor"! " HOTT ELEY Vida SKEET Lib 4 1 fp) bee 4 ow LuV’ / afta it Mite Ng, er Wedigre | i> = “wUV md : ; | yy WJ ayes be 8S P Tee. LET ew et NR HEL ¥ cage Sagaa sme tales ib hid ddd soi ie a be | a) “Tea ay Witt og here WNT TR Ges wns iin, ¥ Rath. Pa : hy eemren cittey, vot! Bye pyar ' Wigner ews vow! Mh wi ry | : y Oa hl pide et . messing FETE PETE Oi apf eTon ee rma eet [Pee L] \ , UU ee ee ro er Bag tS ots rd Mee ay ee ih ‘the. ; : Iya et plore biatetchd aie ° : SANE eeneanvne’ Mme te HLL Fee ee - yw. 2a. a gd | . ~ ; s Roh 2 > "iq Bate CR 244 jh é 4 4¢ Cd ‘ ceyeeae ote 4 we ni diye iii ee” We & Nin £ mh "NA re - ~~ S Sis ALS Abit i tit ~ ‘an, Tadd * a Ste Hess KY ; Litt it A Mans Ad As. aS, nn iy Wu Wye are _~ ‘a ~ md Vie Ve ype! J), R FRELL . ‘ ateows,’,’. AOR Sa ¢ Np a oN -_ A ~ 3% . eo, " f vd Ba oe a Ci a | 4 RAS oe oe SN oe zy m4 ol cada aldo > 2 ise bd s Thi May mf | padded pinehyantwacicinees | la vedng t" nisi an HLT TT ies seit, eee a Ait Wy" “4 PE CO ring 44 yet ddd ue ¥ in oS x A Nand a rete” ery nal A ; . bt] ad "hk on THY ‘, Wes cicete . Bk Vue A reese HTT TE Nes k tes At he px ~ A iT) Len as Bina, Sen ating aa des ane d sere “4H, “Wuyi pal | | | | \ § y ae” * : ; o sp Mntnererri zeNGeG \n ey beer v4 or | N ? ¥ 4 f ah | ’ par! M ley PARAAL es Lt a LH eid 4 LP ie Per LT ' ‘* Lt ee, tay! baht AAP ble hod Hie ws oe 11,1 ihre NK “ We ad MAT 1 Jay DISA, aN Nel | yes eS ke Agen Vy eae ge 8 le Woe wv Reve cee vecul ale yey WAT LL Mince Ah ; i pNeces eer Sen ana ~ w * a ot, air bis MY i Nee Pas 4 Ay VpPa 1 <4 GW ., “ f bol OO wey = 46 tty BE ea ~e i=) ty ty Le Od ee y La) fd | a. yeu) A 38 a ' = \ yiktrve are hd . : eS fmese oy oo HL Fe rve 1 pet x by Bouya, ae ED aed Spetremn Z ists yp eK ee saSlg | Phe es) AT rere Merpiy ” ww rh we ll idtted ah he stqee covaputire Rtv? iweerrly 77 Oo - 14 . loge er ~ ee ey Sreru tte Deere inner Pitti dt adel, Yoel ry hy i fn %. pt we r] q wt. i BSe ¥ ‘HERR GATKE’S VIEWS” ORAS hal ses 2 2B WHITLOCK,” ‘ Author of ‘ Birds of Derbyshire,” de, dc. "he ‘RB. H. PORTER STREET, CAVENDISH SQUARE, W. | 4 a i a a hy frit i ae THE MIGRATION OF BIRDS /L AS, A CONSIDERATION OF HERR GATKE’S VIEWS lo X ona Ne I ¥Z “ BY F. B. WHITLOCK Author of ‘‘ Birds of Derbyshire,” dc., éc. (ALL RIGHTS RESERVED) MEARNS COLLECTION i Cc 2437714 Donodon Born. ee Oe Ba 7, PRINCES STREET, CAVENDISH SQUARE, W. 1897 PREFACE. MieRration has, to me, always proved the most fascinating feature of bird life. I therefore looked forward to the appear- ance of Herr Gitke’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. T soon found, however, that the subject was too great for this tobe 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 Gitke 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. Be BW. 49, Gregory Boulevard, Nottingham. January, 1897. INTRODUCTION. Ir 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 Gitke 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 okservations conducted in a very limited and somewhat exceptionally situated area ; outside this area his personal experience seems to have been very small, ERRATA. Page 2, line 10, for “attitude” read ‘ altitude.” 19, 98, 32, 118, 131, ” ” ” ” 16, for ‘ Anglica” read ‘“‘ Anglia.” 7, for ‘‘west” read ‘‘ east.” 21, for “‘Ochotok” read ‘ Ochotsk.”’ 24, delete ‘‘may.”’ 18, for “parties” read “ partner.” THE MIGRATION OF BIRDS A CONSIDERATION OF HERR GATKE'S VIEWS. DIRECTION OF THE MIGRATION FLIGHT. HAPTER 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 northand south. Whilst Herr Gitke 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 il 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) coals He eK33 ’ 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 — 3 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 Giitke’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 Giitke’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 4 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 Gitke 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. 5 ? 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 Gitke 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 Gitke, 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 Gitke 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, Rooks, Jackdaws, Larks, Swifts, Plovers, Curlews and Geese. These species are mentioned on p. 25, and Godwits, 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 6 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 Redshank, 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 Redwing, 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 preeding haunts—the uninterrupted continuity of the flight being 7 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 Gitke, 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 Gatke. 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 Gitke’s theories are borne in mind, and the small area under notice is not lost sight of. The total Kuropean avi-fauwna, including Neartic and other stragglers, amounts to, in round numbers, 600 species, so that Heligoland can claim fully two-thirds. In considering Herr Gitke’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 dawma.—An example in Lund Museum which may have been obtained on Heligoland. Turdus Pallens.—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, 18438. 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. — One 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 certhtola.—One shot. Cinclus Pallasi.—Supposed to have been seen twice. Saxicola morio.—TIwo shot (this is, more correctly speaking, a south-eastern species). Anthus Richardi.— A 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 Giatke, but not obtained. Charadius fuluus.—Three shot. 9 Charadius caspius.—Two shot, two supposed to have been seen. A total numper 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 superciliosus.—Average visits for fifty years, two per annum. Anthus hichardi.—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 Richard’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 Giitke’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 flights 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 north 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 Huropean 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 Gitke’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 41 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 Giitke’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 avi-fawna 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 Giatke’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 Gitke assigns as the duration of the migratory flight 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 Giitke 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. Referring 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 Hastern Europe and Asia. In presenting evidence of his theory of an east - to - west migration, Herr Giitke 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 Giitke, 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 Gitke, 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. Roughly speaking, the latter includes Scandinavia and the 14 greater part of Hurope 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 Hast 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 Gitke’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 Hastern Asia. It will be observed that Herr Giitke 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 Giitke 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 Rooks 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 Gitke, 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 arule. With regard to the breadth of these flights, the most that has been proved is, that on a certain occasion, viz., October 24th, 1884, 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 Gitke 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 11th 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 11th and 12th one shot by J. A. H. B.; no more till 23rd; eighteen flying north (and Rooks), 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 8.H. 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.E. to 8.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, but 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 Hurope 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, 2.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 Giitke—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 Gitke 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 Rodd 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 Humber. 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 Rooks and Daws (see Migration Committee’s Report). 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 vid 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 Report, 1884, p- 58, 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 Ist, 2nd and 3rd, a continuous rush N.H. to 8.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. Hagle 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 Gitke 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 Giatke 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 Giatke 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 Huro- pean and Asiatic Russia 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 SS” 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 Gitke’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 Giatke’s view this migration of Honey Buzzards was con- ducted in the normal way, 7.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 He 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, vid Western France and Spain to their winter quarters im 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 Gitke is thinking of the Rough-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 Gitke attributes a far eastern origin. With regard to its former breeding range he has collected the following facts—‘‘ According to Pallas (‘‘ Zoogr. Ross. 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 Gitke’s contention is correct that a great proportion of the Shore Larks passing Heligoland are of Asiatic origin, as he describes on 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 Gitke—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 Gitke’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 Kurope, 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 Gitke is correct in assuming an eastern origin of these large flights 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). lLarks, as a rule, on migration, as Herr Gitke 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 Gitke (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 Kast Finmark from the east and are consequently known there under the name of Russian 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 Giatke 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, 7.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 Gitke 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 Gitke 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 Giitke’s theories as to 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 fiocks have migrated to our east coast. But | 29 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 Richard’s Pipit, to both of which Herr Giitke makes very frequent allusion. Though neither have been known to breed, on unimpeachable evidence within the boundaries of HKurope, 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 Hast 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 Yenesay 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 Giitke’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 Gitke, that the majority of the occur- rences in Hurope 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 Kuro- 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 Russia ; 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 Palearctic 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 Richard’s Pipit to which Herr Giitke 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 flights 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 Giitke 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 Richard’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 Richard’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 Richard’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 Giitke 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 Richard’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 Hurope.” 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 Gitke 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 Gitke’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 Gitke’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 wnder exceptional and wndoubtedly meteorological influences adopt at irregular periods, though wm rare instances in comparatively considerable numbers, a western instead of their normal southern autwmnal nugration flight, can reasonably be pronounced only accidental visitors to Ewrope. The more so since even the cases of appearance in greater numbers of this Pupit have occurred mostly at intervals of from six to ten years, viz., m 1839, 1848, 1849, 1859, 1868, 1869, 1870, 1876. On account of prevailing westerly winds A. Richardt 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. Richardi 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 Gitke’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 30 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 Gitke’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 through which they may pass, as new arrivals from over the sea. 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 Gitke 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 Giitke 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 Giitke 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 net 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. Referring to two great rushes of birds in 1892, com- prising Redstarts, Whitethroats, Robins, Pied and Spotted Fly-catchers, Wheatears, Hedge Sparrows, Goldcrests, Grey Shrikes, Larks, Ring Ousels, Blackbirds, Redwings, 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 Rock 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 Ring Ousel, Wheatear, Redstart, 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 Giitke 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 are 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. Onp. 7 of his digest he remarks: ‘‘ Much prominence has been given in some of the Annual Reports issued by the Committee, and in Herr Gitke’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 Gitke most obligingly communicated details of the 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 Richardi, &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. Hagle 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 of 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 Gitke 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 Giitke, 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 Giatke 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 autumn 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 still 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 Gitke, 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 Hurope, 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 he 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 —_ = 4] 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 Gitke, 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 cuides during their migration, Herr Giitke, referring to Richard’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 Gitke’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 Gitke’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 43 Red-spotted Bluethroat. Referring to its geographical distribu- tion Herr Gitke 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 Gitke himself does in other places. This point is of importance in view of the fact that Herr Gitke 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 Giitke’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 Natwralist 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 Gitke 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 Giitke 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 ditticulty 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 [7.c., Heligoland] , asa 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 Gitke 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 Giitke 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 at times when the meteorological conditions are most favourable to the performance of an unbroken flight, 7.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 Gitke’s arguments. In the case of the Shore Lark and Hooded Crow, 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 Hurope, 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 Gitke 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 Giitke 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 Red- throated Pipit, a species breeding abundantly above the Arctic - ni 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 Hast 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. pratensis is very likely to be overlooked. This view is strengthened by Herr Gitke’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, Claus 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 Red-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 Giitke’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 Red-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 Russia and the Baltic provinces. One consequence of this is that the Red-throated Pipit and Siberian Willow Warbler are either not met with at all during migration in the southern parts of the country, cr appear there only occasionally and accidentally ” (‘‘ Bird Life in Arctic Norway’). Turning now to two other species singled out by the author, viz., Hversmann’s Warbler (Sylvia borealis) and the Northern Nightingale (Sylvia philomela) 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 Red-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 to 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 Kurope 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 Gitke 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 Red-footed Falcon, are all birds having their winter quarters for the most part in the south- eastern portions of the Palearctic or oriental regions; and their breeding ranges extend but rarely any distance further westward than long. 25° HE. It would therefore require a very considerable deviation from a direct southerly flight to carry individuals over 4 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 Gitke, 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 Giitke 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 his 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 Huropean 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 Gitke 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 Gitke 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 Gitke 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 Hurope, 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 Giitke’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 autumn 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 Palearctic 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 11th 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 rowte 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 Giitke’s theory of migration, conducted in a broad o4 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 Gitke 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 20, 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 ; 50 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 Kurope, 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 Giitke. 56 ALTITUDE OF THE MIGRATION FLIGHT AND METEOROLOGICAL CONDITIONS WHICH IN- FLUENCE MIGRATION. HOUGH Herr Giatke 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 Giitke 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 eee 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 Hast. . . . 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 Gitke’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 alsoabnormal. 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 Gitke 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. Thereis 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 theearth. 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 Gitke—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 — Giitke 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 4 59 negative evidence afforded by the absence of certain birds in particular years; direct proof is of course practically unattainable. There is also another point worth noting, Herr Gitke describes migration proper as being conducted at both periods of the year in one unbroken and for the most part nocturnal flight, the un- broken character being more pronounced in the spring than in the 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 Gitke’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 Giitke’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 Gitke adds that—‘‘ 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, itis 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 Giitke 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 — ——_——_ a 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, 7.e., in the Hebrides, depends entirely on our acceptance of Herr Gitke’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, 7.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 nocturnal flight.” This supposed possession of a sense enabling birds to detect the state of the atmosphere at heights exceeding four 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 hundred 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 supposed 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 Giatke’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 Giitke 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 Gitke 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 Gitke frequently refers to Richard’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 Gitke’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 Gitke 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, 7.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 ([bis, 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 Giitke also alludes as an eastern one, as though it were absolutely confined 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 Bodé in the north, and Toulon, Biarritz and Corunna in the south, as well as all parts of Great Britain and Treland. 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 speciés are of an even-flowing and 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. ‘ ~~, Vow cr ara i Phetayes Atl Nj ftnan am Ba? Laan 44, ar A $ > Ae gi : a aaana seh a0 Seay PTI, ~ bas fri gmnnnn rl as ; DA nyt 4 bee 45% a a, we J og 4.@ ae || _ Pee Trtita¢ dda tid4 rw a ilucl qf bp Ne ia Ne aa AAaecest r e- f aan ot oe ane at, 4asean amt @'la\ NU UA laden THT TY laa, A ULL Pps TT tg “ Pheosas! ve Ov cc tl {| Tear Faerie ts ; ‘ A x ° : ) me Cane, ee || hy iy SENT ie wa ig . a ead, Qe oF Aan led ae ees NA? ig oy el ial *) ; ats At Ayes: cea) ean - “Se ae \ My WW | nd oa clad ol ALE Le ef bg Athy gaannd? ‘ “. RE Re 4 a Ps ee if Bag gaat en ap Paper yoy sd) dia pany! a . hm A > is. v wT ry # hy -~ er ba a. a a = - a vA, sal ae we : . & 4 Y 3 Lo eae SOE MUON Mg HWY, ae p q 1 v Ms ene 4 & if Se ootiuiaAaatn,. s, a Rada SN a nO AAA TUT ~ YQ ran ~s ang - ’ Vv * q - ater se Fa," s a, ap ay al Hayy oe ShOLot es NO yaw rin, LTT ‘ Pa Sea, mn ® £ iad | Yr Ff % > fi re’ ss pan | a | ; Beal AL! opUie tM. PAL i ven YY Vi Ay. *3: * Ap ; men a (ft Wii) heh ot toate 1) MTT hme wel Ra eg: MNase ty mY) {jf a YY. ‘Ap. o iil 7: AF \ rie at YY Art|. LT} Gin. pee Si yy lay, all 4a 4 i] cm mr Geen ~ ee mm LT ow seen ey =< . A 5 Nev's pe -@Ae a. (8h aN ae =v Oa, YH IT TTL TTT one etry AY Coa RTYTY WA aaher NAR he an PTR Na r | Mas VW tunel re ayy soi apnnatens Ware a 4.6... 3” sishalshtniae 4g y= Tidtt ath erry ee ai Mariage Male he - y re aana “* ere) a lalanl a janmAaAn4 aa, an ia” 7iN\A AA ~ tan *F rin! Tiere Nthien Hy aunieidtaarese P r qa , A. aR 0 AAMR Dn O07 he. eal Min ie ry Y Val tea, | yi paneneeiNN| | lathes ~ca Ahr Age (RAR AAS an re. | ty ra * WA San a4 shana nas ry of ets bl LL . MOR Py ide ITT AMA AA la aa (44) a pp saulat Ty Ny mt | ORR. \e Bg ey val A VAN a aay an wed | rf AAliitinesaaninns ep 5: panini MMT TTT | UM atv ins ina, > (Aang i enn UAB SRE Perr TT) AANA aha, , Talal | 7 arn AA ar Tang haat PHERNARA aa MAAR AD nag Tt ann elven ys HW uot pemceeel =e Ana.e ARAL. 4 ya egal (ae an, oeL an, a2” Py iat ttol CL sitet, Wad pausrshanaNlal if aaa afte ' WA TAH nn’ 7 Aan aPrnents! a yaapanneh’ eee War idelet 4 A ‘ a. Til he, 1 ¢ AMsads : aah | J) Pa N told wT) ‘8 “4 Perea | pra seseh Py AAODs ey) parm arrhase fa ar’ nf >. Pa &. P ry an aa = ay.) » oe (VSS SS ey Nay Aah & 4 ama. A rT val) e —