ON THE MIGRATION OF BIRDS. 453 
observers were volunteers, the nature of the data obtained is most satis- 
factory. It has proved to be adequate for the purpose of the inquiry, 
and surprisingly accurate. Indeed, it is often quite wonderful how the 
observations made at a particular station are borne out by the records at 
others. 
The object of the enquiry was to obtain full and trustworthy infor- 
mation in connection with the migratory movements of birds as observed 
on our coasts, and not to solve problems connected with the causes 
of the phenomena, the evolution of the migratory instinct, or other purely 
theoretical aspects of the general subject. 
As regards the importance of this investigation, it must be borne in 
mind that the observers were most favourably stationed for witnessing 
migration in its various phases, and that such a voluminous and complete 
set of observations has never been amassed at any previous period in the 
history of the study of bird-migration. Its special nature can only be 
fully appreciated when it is realised that, in order to study the pheno- 
mena of bird-migration in the British Islands, it is necessary that the 
data upon which any deductions may be satisfactorily or safely founded 
should be based upon observations taken synchronously at stations encir- 
cling the entire coasts. This cardinal and most important condition has 
been attempted and accomplished for the first time, either in this or any 
other country, through the labours of the Committee. 
The meteorological aspect of the subject has received very careful 
attention, and with interesting and important results. In connection 
with this portion of the work the ‘ Daily Weather Reports’ issued by the 
Meteorological Office have been consulted and correlated with the data 
relating to the migratory movements for each year of the inquiry. 
Finally, I may state that the results now communicated are based ab- 
solutely upon the records obtained by the Committee ; and, also, that I 
have approached the subject with an open mind and without preconceived 
ideas. I have considered this not the place for theory, but for the esta- 
blishment of facts, and for deductions drawn from a direct study of the 
observations placed in my hands. 
Birp MIGRaTION AS OBSERVED ON THE BritTisH AND IrisH Coasts. 
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 is readily accounted for. 
First, the Geographical position of the British Islands is eminently 
favourable. Placed, as our Isles are, between South-western Europe and 
the Scandinavian Peninsula, Iceland, and Greenland, they lie directly in 
the course of the legions of migratory birds which annually make a double 
journey between their northern summer and their southern winter 
quarters. For these Birds of Passage our shores form not only a main 
and much accustomed highway, but afford convenient resting quarters. 
Secondly, our Islands have a vast bird-population of their own, and 
the majority of these birds belong to purely migratory species. Some of 
them are either Summer Visitors from the southern regions or Winter 
Visitors from continental Europe, Iceland, «ec. 
Thirdly, many individuals of species which are sedentary in our Islands 
are strictly migratory. This is especially the case in the more northern 
