i897-] VhiM%'^'— The Migration of Birds. ii 



touched. The records on which the Report is based were 

 made from 1880 to 1887. 



The vast array of facts collected was arranged in a schedule 

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

 (2) coast, (3) station, (4) in what numbers, and (5) whether 

 the occurrence was during the day or night. The results given 

 are based on the whole of the information received from all 

 the coasts. It is found to be impossible, at certain seasons, to 

 distinguish between widely different /emigratory and Emi- 

 gratory movements without consideration of the whole of the 

 observations ; the non-realisation of which fact has hitherto 

 lead to misconception. 



It is manifestly impossible to conduct anything approach- 

 ing a reall}^ complete enquiry over the entire British area. 

 Remembering the peculiar difficulties besetting such an 

 investigation, the nature of the data obtained is satisfactory, 

 and has proved surprisingly accurate and adequate for the 

 purpose. It is often astonishing how observations made at 

 one station are borne out by the records at others. 



As to the importance of the enquiry, such a voluminous set 

 of observations, made from the most favourable situations for 

 witnessing bird-migration, has never before been amassed. 

 The special nature of the work can only be fully appreciated 

 when it is realised that in order to study the phenomena of 

 bird-migration in the British Isles, the data on which deduc- 

 tions may be satisfactorily founded must be based upon 

 observations taken synchronously at stations around the 

 entire coasts. This cardinal condition has been accomplished 

 for the first time in anj^ country through the labours of the 

 Committee. The results given are based absolutely upon the 

 records obtained by the Committee, and the subject has been 

 approached without preconceived ideas. The Dailj^ Weather 

 Reports of the Meteorological Office have been consulted and 

 correlated with the data relating to the migratory movements. 



Bird-migration, as observed in the British Isles, is perhaps 

 more complex than in other regions, for our isles, lying be- 

 tween south-western Europe and the Scandinavian peninsula, 

 Iceland, and Greenland, are directly in the course taken by 

 legions of birds which annually make a double journey be- 

 tween their northern summer homes and their southern winter 



