254 



KNOWLEDGE 



[KoVEMBEB 2, 1896. 



Messrs. Sniitli, Kldor, & Co. liavo in tlio press a work bv llie Rev. 

 11. \. Ifiiti'tiinsiin, author of " Kxlinct Monsters" nnd otlier works, 

 entitled " I'reliistorie Man nnd Beast." Sir Ilenrv II. lloMorlli, 

 M.l'., F.R S . eontribvites a prefaee. Tlio book will be iUiislraterl 

 with origiiinl drawings by Mr. C'eeil Aldin. 



: ^ 



BIRD MIGRATION IN GREAT BRITAIN AND 

 IRELAND. 



EeIH^RT ok the CllMMITTEE 01' THE BlilTISlI ASSOCIATION. 



BIRD migration, although a subject about which 

 very little is known, has always proved an ex- 

 tremely fascinating one to ornithologists, and, as 

 a consequence, a large amount of literature on 

 the subject has resulted, some of it dealing with 

 acts, but more often it has been of a speculative character. 

 The British Association determined to give their careful 

 attention to the subject, and accordingly a committee was 

 appointed to investigate the matter. This committee con- 

 sisted of the following well-known ornithologists : — Prof. 

 Newton, j\Iessrs. John Cordeaux, .J. A. Harvie-l!rown, K. M. 

 Barrington, W. Eagle Clarke, and Rev. E. P. Knubley. 



By a system of schedules all the birds observed at 

 two hundred and three lighthouses and lightships round 

 the coasts of (Ircat Britain and Ireland, from the years 

 1880-1887, were accurately recorded, as well as the times 

 and dates of their passing. One hundred thousand records, 

 culled from several thousand schedules, were thus obtained. 

 It can easily be imagined what an enormous task it was to 

 reduce this mass of information to an intelligible form, 

 so as to make it of real scientific value. This, however, 

 has now been done by the energy of Mr. W. Eagle Clarke, 

 and the outcome of his years of labour is the report 

 which was read at the Liverpool meeting of the British 

 Association. 



I propose here to give a brief summary of this report, 

 and to extract from it the most salient and important 

 facts elicited by the inquiry. "The migration of birds, 

 as observed in the British Islands, is a very complex 

 phenomenon ; more so, perhaps, than in any other region 

 of the globe." This may readily be seen. By their 

 geographical position the British Isles form, not only a 

 main and much accustomed highway, but convenient 

 resting quarters for legions of migratory birds, which 

 annually make a double journey between their northern 

 summer and their southern winter quarters. Again, we 

 have a vast bird population of our own, and the majority 

 of these are purely migratory species, while nearly all are 

 migratory to a certain extent. We have a further compli- 

 cation in the fact that our variable climate causes much 

 irregular migration. Having said so much, to show with 

 what an extremely complicated but fascinating problem we 

 are dealing, let us pass on to review it in some detail. 

 Mr. Clarke has confined himself entirely to facts, 

 . which are discussed under the following sections : 

 geographical, seasonal, and meteorological. It may be 

 explained here that the terms "immigration" and " emigra- 

 tion," used below, mean respectively migration to, and 

 migration from, our shores, while the term " migration" 

 is used in a general sense. 



Geographical. — Intermigrution betireen Britain and 

 Xorthi'rn Continental F.nropc. — Between Britain and 

 Northern Continental Europe travel a host of migrants, 

 which are either birds of passage on, or winter visitors to, 

 our shores. 



" These immigrants and emigrants from and to Northern 

 Europe, pass and repass between this portion of the 

 Continent and Britain by crossing the North Sea in 

 autumn in a south-westerly direction, and in spring in a 

 north-easterly one, and while the limit to their flight 



in the north is the Shetland Islands, that on the south 

 extends to the coast of Norfolk." 



" After arriving on our eastern shores, these immigrants 

 from the north, some of them after resting for awhile, 

 move either down the east coast, m mutf for more southern 

 winter quarters, or, if winter visitors, to their accustomed 

 haunts in Britain and Ireland." 



" The west coasts do not receive itirectly any immigrants 

 from Continental Europe." 



lntermi<iration hetircen tJw South-East CooHt of EMjland 

 and till' Const of ]]'csti'rn FAirajie, or the East and West lloute. 



" During the autumn, day after day, a stream of 

 migrants, often of great volume, is observed off the coast, 

 flowing chiefly from the south-east to the north-west at 

 the more northerly stations, and from east to west at the 

 southerly ones, across the southernmost waters of the 



North Sea These important immigrations set in 



during the latter days of September, reach their maximum 

 in October, and continue at intervals until November." 



" It is satisfactory to find decided evidence that the birds 

 retrace their flight to the north and east along precisely 

 the same lines as those along which the autumnal southerly 

 and westerly journeys were performed. Thus in the spring 

 these birds depart from the same sections of our eastern 



seaboard as witnessed their arrival in the autumn 



Whether this east to west stream is a branch of one that 

 passes down the coast of Continental Europe, or whether it 

 has its source in Central Europe, is a matter of conjecture." 



This interesting migration route is one of the discoveries 

 of the inquiry. Formerly it was thought by some that in 

 the northern hemisphere there was no migration route 

 trending north in autumn, or south in spring. So con- 

 vinced was Mr. Charles Dixon of this, that he actually 

 founded a laic of dispersal on the supposed fact. The 

 present enquiry has now abolished this fact, and with it 

 Mr. Dixon's "plausible" theory. Another remarkable fact 

 brought to light is that Heligoland and England draw 

 their migratory hosts from different sources. Herr Giitke, 

 who has done so much valuable and practical work in 

 connection with migration in Heligoland, thought that 

 the birds passing over that island were on their way to 

 England. Mr. Clarke, however, comes to the conclusion, 

 by careful comparison between our observations and Herr 

 Gatke's, that this is not so. 



Besides the routes already discussed there are others, 

 but want of space compels me to pass them over without 

 comment. They are ; — 



" Intermii/ration beticeen Britain and Faroes, Iceland, and 

 Greenland : Litermigration bcUreen Great Britain and Ireland 

 and the South : East Coast of Great Britain ; West Coast of' 

 Great Britain : Irish Coasts : South Coast of England : 

 Channel Islands." 



We now come to the seasonal section of the report. 



"In the autumn the birds, when they appear on our 

 shores, have accomplished the great business of the year- 

 procreation. Food is still abundant in their favourite 

 resting haunts, and hence there is no particular hurry to 

 move southwards. Thus many species tarry on our coasts 

 or in their vicinity, some for a considerable period. Their 

 numbers are, of course, incomparably greater than during 

 the northward journey, as they are swelled by the 

 numerous young birds, now a few weeks old. All these 

 circumstances and conditions combine to make the autumn 

 movements comparatively easy of observation." 



" In spring the all-absorbing duties of the season and 

 the procreative influence are upon the voyagers, and the 

 birds usually hurry on after a short sojourn for rest and 

 food only. Thus the spring movements do not afford 

 much facility or opportunity for observation," 



