SCIENCE-GOSSIP. 



277 



THE MIGRATION OF BIRDS. 



TT is only by a careful and systematic record of 

 trustworthy observations that we may expect 

 to unravel the mystery of bird migration. Most 

 writers on the subject have hitherto depended upon 

 desultory and scattered records with which to found 

 theories ; some of them, though fantastic enough to 

 please the most ardent lover of the wonderful, no lon- 

 ger need occupy the attention of the serious student of 

 nature. As is well known, the British Association for 

 the Advancement of Science some time ago appointed 

 a committee to collect records from lighthouses 

 and lightships around our coasts. With the 

 approval of the Board of Trade a systematic 

 record of bird visitants to outlying lights during 

 migration times has been collected by the keepers 

 of lighthouses and lightships. The birds, attracted 

 like moths to the lights, often fall stunned or dead 

 in great numbers round the lanterns. These are 

 picked up by the attendants and noted, identification 

 being secured by cutting off one of the wings and 

 attaching it to the record. At some lights in the 

 main line of migration on still dark nights multitudes 

 of birds are killed in this manner, thus giving ample 

 material for studying the direction of flight, the 

 different species passing and their estimated 

 numbers. 



We have been favoured by the Honorary Secretary 

 to the Committee above referred to (Mr. John 

 Cordeaux) with a report submitted to the meeting 

 of the British Association at Liverpool last autumn. 

 It consists of an important digest of the observa- 

 tions made from 1880 to 1887. This Committee 

 consists of Professor Newton (Chairman), Mr. 

 John Cordeaux (Secretary), Mr. John A. Harvie- 

 Brown, Mr. R. M. Barrington, Mr. W. Eagle 

 Clarke and the Rev. E. P. Knubley. As many of 

 our readers are interested in this subject, we have 

 pleasure in quoting the leading conclusions to which 

 the Committee have arrived. These extracts will 

 be found the more seasonable as the spring migra- 

 tion will shortly be in full flow. 



"As has been before stated at meetings of the 

 Association, this Digest is the work of one of 

 their number, and the remaining members of the 

 Committee have to record their deep sense of the 

 obligation under which they lie to Mr. William 

 Eagle Clarke, of the Science and Art Museum, 

 Edinburgh, for the assiduity with which he has so 

 long laboured on the enormous task he undertook, 

 and to congratulate him on the success with which 

 he has overcome the countless difficulties it 

 presented." . . . 



" It cannot be doubted that henceforth, as 

 regards the British Islands, there is now 

 established a firm basis on which may rest a 

 sound and proper conception of many of the 

 phenomena of British migration, for this Digest 

 contains a plain statement of ascertained facts, and 

 is wholly free from theory or speculation of any 



kind. Thus it will be found to differ from almost 

 everything that has hitherto been published on the 

 subject. In saying this much your Committee 

 would, however, guard themselves from the 

 inference that the business is exhausted : on the 

 contrary, a very great deal more is yet to be 

 learned from a further examination of the obser- 

 vations which have been collected at the light- 

 houses and lightships, while the whole subject of 

 inland migration is untouched. Whether it will be 

 possible for the Committee to proceed further 

 must entirely depend on the action of the Associ- 

 ation ; but they may say that Mr. Clarke, so far 

 from being deterred by the magnitude of the task 

 with which he had so successfully grappled, is 

 willing to work out the details of migration for 

 each of the species to which the observations 

 refer, and has even already begun to do so ; and it 

 is to be hoped that he will receive some encourage- 

 ment to continue such useful work. And the 

 Committee may remark that the very considerable 

 funds that private generosity has placed at their 

 service are now exhausted. 



" Though on the present occasion the thanks of 

 the Committee are so certainly due to Mr. Clarke, 

 they feel that, while presenting what may be their 

 final report, they must again acknowledge their 

 indebtedness to all who have helped them in 

 prosecuting their inquiries ; first, to the Master 

 and Elder Brethren of the Trinity House, the 

 Commissioners of Northern Lights, and the Com- 

 missioners of Irish Lights ; but more especially to 

 the men of the several lighthouses and lightships, 

 without whose cheerful and intelligent co-operation 

 nothing could have been done." 



Following this comes Mr. Clarke's conclusions : 



" In presenting this Digest of the results 

 obtained concerning the migration of birds, as 

 observed at lighthouses and lightships around 

 the coasts of the British Islands, during the years 

 1880-18S7 inclusive, to the Committee appointed 

 by the British Association for the investigation 

 of that subject, I beg to offer an explanation 

 regarding the lapse of time that has taken place 

 between my appointment and the completion of the 

 work. In a word, this has been entirely due to the 

 magnitude of the undertaking. 



" I was instructed to base the Digest upon an 

 examination de novo of the whole of the information 

 furnished to the Committee during the eight 

 years of its active existence. Thus the whole of 

 the data required to be reduced to order before it 

 was available for the purposes of the Digest. 

 Moreover, at the outset there presented itself for 

 consideration an extremely perplexing problem, 

 namely : how to treat or arrange such a vast 

 array of facts on a systematic plan which would 

 render them comprehensive and at the same time 

 suited to the inquiry in all its varied aspects. It 

 was not until a number of abortive attempts had 

 been embarked upon that a plan was devised which 

 met the very special requirements of the case. 

 The scheme finally adopted took the form of a 

 schedule. This was designed to show graphically, 

 for each species during each month, (i) on what 

 day ; (2) coast ; (3) station ; (4) in what numbers ; 

 and (5) whether during the day or night the 

 particular species was observed during the particular 

 month and year. It is needless to remark that 



