88 Wild Life in Wales 



sipated altogether, adding considerably to their smoke-like 

 appearance, but time after time they will be re-formed in 

 almost exactly the same spot. The preference for the 

 vicinity of trees is no doubt partly accounted for by the 

 shelter they afford, but is likewise probably due to the heat 

 radiated from their leaves for some time after the rays of 

 the sun have ceased to strike them. In fine, settled weather, 

 the columns often rise high above the trees, so as to be lost 

 to our vision ; but they are followed by the Swifts and 

 Swallows, which, being easily seen, then obtain all the credit 

 attaching to the weather-wise, without reference to cause 

 and effect. It is an old and popular belief that 



" When the Swallow flieth high, 

 Then the weather's always dry ; 

 But when she lowly skims the plain, 

 Ere the morrow there'll be rain." 



And, though doubts have sometimes been cast upon it, in 

 this incredulous age, the belief is probably founded upon 

 more substantial grounds than many similar bits of weather 

 lore, but the possible insect link in the chain of circum- 

 stances is commonly overlooked. That other birds, as well 

 as " swallows," delight to sail about in the higher atmosphere 

 in fine weather, is familiar to all ; but from their actions 

 when aloft, it is not difficult to see whether they are feeding, 

 or merely flying for sheer enjoyment. Very often it will 

 be obvious that the former is their object, and it is easy to 

 imagine that the ethereal bodies of small insects may be 

 especially sensitive to climatic changes. Some idea of the 

 height to which some insects will ascend may sometimes be 

 formed when, happening to be pretty high up upon a 

 mountain side, we see Starlings, Swallows, or Swifts, engaged 

 in insect hunting far overhead. I have frequently observed 

 Black-headed Gulls so employed above the summits of the 

 Welsh mountains, as well as in other places ; the insects 

 they are after being (as proved by dissection of some of 

 the birds killed) largely Craneflies and Beetles, though an 

 occasional Moth (Plusia gamma and Char<eas graminis) has 

 also been found in their maws. 



