252 Miss Baxter and Miss Rintoul on the [Ibis, 



route. This question of alternative routes is a difficult 

 matter to prove beyond a doubt, but there is a good deal of 

 evidence whicii seems to us stronfi;ly in support of our theory. 

 This we will detail as briefly as possible, dealing with autumn 

 movements for the sake of convenience, though it must be 

 understood that the same remarks apply to the spring- 

 migrations. 



Firstly. There is the fact that, should a westerly type of 

 weather prevail during the whole migration-period of any 

 given species, such as Bluethroats, Barred and Yellow- 

 browed Warblers, Scarlet Grosbeaks, Northern and Siberian 

 Chiffchaffs, and many others, these birds will not be seen at 

 our migration-stations. Should, however, the wind change 

 to an opposite direction during the period of their migration, 

 these species will at once make their appearance on our 

 shores, travelling, no doubt, along that " bridge of fine 

 weather" which Dr. Eagle (.larke, in his "Studies of Bird 

 Migration," has shown to exist between the Continent 

 and Great Britain under these meteorological conditions. 

 Should the easterly type of weather not extend far enough 

 to the east of our islands, the Asiatic species will not 

 appear, although we may be visited by birds from northern 

 and central Europe. In the autumn of 1912, late in 

 September, we had easterly and south-easterly winds and a 

 large rush of birds, including Little Buntings, Red-breasted 

 Flycatchers, and Barred Wai-blers ; in view of our former 

 experiences we expected Yellow-browed Warblers, but none 

 came under observation. On studying the meteorological 

 conditions we found that, previous to and during that time, 

 the weather conditions favourable for bringing this species 

 to our shores did not extend sufficiently far east to influence 

 its movements. 



Secondly. If the easterly type of weather comes late in the 

 season, an entirely different class of birds to those we get 

 earlier in the year comes with it, thus proving, in our opinion, 

 that the birds do not wait for this type of weather to perform 

 their migration journey, but proceed to their winter quaiters 



