WINTERING OF SWALLOW TRIBE IN S. HANTS. 305 



England. The incident is unique, I presume, in the annals of 

 ornithology. 



Neither is the following inference correct : " It is not im- 

 probable that at the very last the right wind blew, and carried 

 them in a few hours to summer climes." No ! One of the two 

 Martins doggedly remained on, and undoubtedly perished on 

 Jan. 23rd. I have no doubt whatever that the birds remained 

 in spite of favourable winds for a good and sufficient reason, 

 which I will endeavour to explain ; and I am of the firm opinion 

 that the birds deliberately chose to remain, and that wind-direc- 

 tion had nothing whatever to do with their stay. The predomi- 

 nating factor, in my opinion, was a plentiful siqiply of proper 

 food, and this abundance is accounted for in several ways. The 

 locality favoured by the birds is well sheltered, as already stated, 

 and the climate of the district is mild even in winter, and insects 

 abound in the immediate vicinity of the stream, which the birds 

 haunt so closely. 



Without doubt this stream is the secret of the abundance of 

 insect-life. A part of the water of the stream comes from a 

 number of springs about a quarter of a mile away, but the 

 volume of water is greatly augmented by the surplus water from 

 the pumping-station of the waterworks, and a large quantity of 

 heated water enters the stream from two parchment works. Now, 

 as this heated water passes along the stream it produces a 

 luxuriant mass of vegetation for a considerable distance before 

 entering the sea, and in cold weather a perceptible mist is 

 observable several feet above the surface, showing that the water 

 is several degrees higher than the surrounding air. This humid 

 condition favours the rapid and constant production of insect- 

 life, so that it is no uncommon thing to see clouds of gnats 

 hovering over the stream and its vicinity in the depth of winter. 

 One only needs to see the numbers of birds, constantly on the 

 feed along the banks, to know that suitable food is there in 

 plenty. 



To watch half a dozen Pied Wagtails in different places along 

 the course of the stream busily feeding is a common sight every 

 day. They fly (or flutter) down stream, and occasionally hover 

 in the air just clear of the surface, and snap up the insects from 

 the water ; curious and amusing is it to watch them as they 



