1 92 1.] Bird-Migration h/ the Marling Method; 467 



afforded by tho device of " bird-marking " and camo to a 

 gradual end during tli(> war. Two interim reports have 

 ah-eiu]y been ])ublished : the first (19)* gave full details of 

 all results obtained up to the summer of 1912, without any 

 attempt to draw conclusions therefrom, and it may be of 

 value as giving a fair sample of the kind of data obtainable 

 by this mdtliod, although publication of the remaining results 

 in such bulky form has been considered unnecessary. The 

 second report (20) gave only brief notes on such further 

 records, up to the spring of 1915, as were of particular 

 interest. The writer has also read papers before the Royal 

 Physical Society of Edinburgh (18) and the Zoology Section 

 of the British Association for the Advancement of Science 

 (1912 Meeting), setting forth the general scope and purposes 

 of the methotl : in these and some minor papers a few early 

 records were quoted_, but they were also included in the 

 first report. The purpose noAv in view is to summarise 

 all the data in systematic form, and to give such conclusions 

 as seem warranted eitluu- as to the value of the method or as 

 to the facts and problems of bird-migration itself. 



The writer carried on the inquiry as a piece of research 

 from the Natural History Department of the University of 

 Aberdeen, under the general direction of Prof. J. Arthur 

 Tliomson, LL.D. From 1910 to 1914, inclusively, most of 

 the working expenses were covered by a grant from the 

 C!arnegie Trustees. A debt of gratitude is due also to those 

 who co-operated in the actual marking of birds, as well as to 

 the many correspondents who kindly supplied information 

 as to '"reappearances.'" The help in the central routine 

 work of the inquiry rendered at different times by the late 

 Mr. Lewis N. Gr. Ramsay, M.A., B.Sc, by Mr. James Ewing, 

 M.A., D.Sc, and by Miss Maribel Thomson, M.A., B.Sc, 

 calls for special mention ; the last-named took the writer's 

 place, as regards this work, throughout the war. 



It should be stated that the work of marking was at its 



* The numbers in parenthesis refer to tlie references given in 

 Section XIII. (p. 526). Jteferences not relating to the marking method 

 ,'ire quoted in the text. 



