WEATHER INFLUENCES 179 



however, what even small birds can brave, in the shape 

 of high winds, for a time, but a long flight against such 

 heavy odds is disastrous. Blackbirds have appeared at 

 the Eddystone when the wind registered a velocity of 

 40 miles an hour. Gales during the autumn drive 

 marine species, such as Phalaropes, Skuas, Petrels, etc., 

 and even Gannets, on to our shores (some of them 

 occasionally in great numbers) and sometimes far 

 inland. Later in the season, in winter. Guillemots, 

 Razorbills, Puffins, and Little Auks, are, in like manner, 

 blown ashore from their pelagic winter haunts, and 

 are not unfrequently carried far into the interior of the 

 country. 



Temperattu^e. — Temperature plays an important part 

 in both the spring and autumn movements. In the 

 spring, a decided increase in warmth in the more 

 temperate winter retreats is an incentive to move 

 towards summer haunts ; and it has almost invariably 

 been found that the earlier arrivals of such migrants on 

 our shores are to be correlated with a rise of temperature 

 in countries to the south of the British Islands. It is 

 worthy of note that, in not a few instances, such move- 

 ments have been recorded for dates on which the 

 temperature of our islands was lower than immediately 

 before the birds appeared— a fact which clearly indicates 

 that the increase of warmth at the seat of emieration 

 was the incentive for the movements northwards. This 

 rise in temperature in South-Western Europe sometimes 

 extends to the British area, prevailing over it to a greater 

 or lesser extent. 



In the autumn, a decided fall in temperature warns 

 the summer guests that the time to seek the southern 

 winter retreats is at hand, and later compels the laggards 



