OBNITHOLOGICAL REPORT FOR NORFOLK. 165 



although they have been impugned, I have a great respect, cites 

 "the simple fact that, whereas birds appear in great number 

 when the wind is in a particular direction, they are scarcely seen 

 at all when it is in some other quarter " (' Heligoland,' p. 74). 

 This was the opinion of the veteran observer, but it has 

 been challenged by later writers. In another place he says : 

 " All species, without exception, approach in largest numbers to 

 the earth's surface when very light south-easterly winds, accom- 

 panied by clear warm weather, happen to prevail for any length 

 of time in the lower regions of the atmosphere " (T. C, p. 76). 

 If this be true of Heligoland, it is probably equally true of the 

 coast of Norfolk. 



It has to be remembered that the wind often changes two or 

 three times in a day, and observers do not always keep pace 

 with these changes. Take the following, which is only one entry 

 among many : " September 9th, 1913. At 7 a.m. the wind was 

 E. at Northrepps, at 9 a.m. it was N.N.E., at 10 a.m. it was 

 N.N.W., at 4 p.m. it was due N." These readings were from 

 the clouds, which I generally find to be the best weather-cock. 



Again, there is another point not to be forgotten, namely, 

 that migrants cannot be much affected by any wind except that 

 through which they are passing. Now migratory birds commonly 

 travel high, and it may not unfrequently be observed upon the 

 coast of Norfolk that, while the lower stratum of clouds is moving 

 with the wind at a fair pace, the higher ones appear to the eye 

 as absolutely stationary. Accordingly, if the birds have just 

 descended from a height, it is not the lower stratum which has 

 governed their movements but the upper. 



This was first remarked by a very acute observer, Mr. F. D. 

 Power, who formerly visited the Norfolk coast every autumn, and 

 was led by long experience to attach great importance to wind 

 in its effect on birds. In a little work entitled ' Ornithological 

 Notes from a South London Suburb,' which deserves to be better 

 known, Mr. Power says : — " These contrary currents may often 

 be observed in studying the movement of the clouds, and I have 

 many times seen migrants on passage against this higher wind 

 at such an altitude that, had not my attention been attracted bj' 

 the traveller's notes, I should have missed the movement alto- 

 gether " (p. 58). Gatke, who observed this, speaks of sometimes 



