304 STUDIP:S in JilRD-MIGKATION 



this station was very favourably situated — probably none 

 more so — for observinof the meteoroloorical conditions 

 which made for or against emigration. 



No movements were witnessed, either by day or night, 

 on the part of land-birds, under weather conditions which 

 could be described as unfavourable for crossing the 

 Channel. 



The force of the wind is the main factor which 

 determines what is favourable and what is unfavourable 

 for the movements. From observation, I am convinced 

 that the direction of the wind is, in itself, of no moment 

 to the emigrants, for they flitted across the Channel 

 southwards with winds from all quarters. It is quite 

 the reverse, however, when its force or velocity comes to 

 be considered, and I found that none of the movements, 

 not even the straggling flights during the daytime, were 

 performed when the velocity of the wind exceeded 28 

 miles an hour (or force 5, fresh breeze, of the Beaufort 

 scale). With the velocity of the wind at 34 miles an 

 hour (force 6), odd Pipits and one or two young Swallows 

 were indeed seen in distress, .and endeavoured to seek 

 shelter at the lighthouse. The movement witnessed on 

 the early morning of 23rd September afforded an 

 interesting instance of the effect of the force of the wind 

 on migration. On the wind falling from a velocity of 

 40 miles an hour (force 7) to 23 miles an hour (force 4), 

 the other meteorological conditions (direction of wind 

 and heavy rain) remaining the same, the great emigra- 

 tory movement already described was initiated. 



Later observations made in spring, however, demon- 

 strated that Starlings, Thrushes, and other medium-sized 

 species cross the Channel when the wind attains to a 

 velocity of as much as 40 miles an hour. This, how- 



