467 
1921 .] Bird-Migration by the Marking Method. 
afforded by the device of “ bird-marking 55 and came to a 
gradual end during the war. Two interim reports have 
already been published : 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 method, 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 method : in these and some minor papers a few early 
records were quoted, but they were also included in the 
first report. The purpose now in view is to summarise 
all the data in systematic form, and to give such conclusions 
as seem warranted either 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 
Thomson, LL.D. From 1910 to 1914, inclusively, most of 
the working expenses were covered by a grant from the 
Carnegie 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 r 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 the references given in 
Section XIII. (p. 526). lie Terences not relating to the marking method 
are quoted in the text. 
