208 PROCEEDINGS OF THE 



indeed, whicli are at this moment in the estuary, suggest the 

 probability of some of the nearly allied North American forms 

 being present. 



There can be no doubt that the immense numbers of these 

 birds at j^resent frequenting the Forth have been attracted by 

 the shoals of Sprats or Gar vies which at full tide are swarming 

 near the surface of the water. These fish are taken in prodigious 

 quantities in nets by the fishermen, who dispose of them in cart- 

 loads. The selling price being about 10s a ton, the farmers in 

 the neighbourhood use them as manure. We saw entire fields 

 spread over with Sprats, and men busily employed in ploughing 

 them in. 



No doubt need be entertained, I think, as to the origin of these 

 immense flocks of sea gulls. They cannot be looked upon as 

 off'shoots from British nurseries, but are strictly of Arctic parent- 

 age. The presence of so many Glaucous and Iceland Gulls I 

 think clearly shows this. 



In conclusion, I may add a word of summary. The experience 

 of the past fortnight has shewn me that the Glaucous Gull has 

 occurred in very large numbers during the present winter, and 

 that the Iceland Gull — a still rarer bird — has also been seen in 

 much greater numbers than we have any previous record of. We 

 have likewise seen that the Kittiwake, usually accounted a 

 migratory bird, and entirely absent, or nearly so, in winter, 

 is moving about at present in thousands in the firth, and that 

 their presence is wholly due to the abundance of food. Whether 

 they have travelled southwards from Arctic seas in the im- 

 mediate train of the fish I am not able to say, though, from 

 their extraordinary numbers, it may be presumed so. I can only 

 further recommend the field to the notice of ornithologists as 

 furnishing a rare opportunity for studying the flight and habits 

 of several of the rarer species, and I must cordially thank Mr 

 Thomson for having drawn my attention to such an unprecedented 

 influx of Arctic gulls into our Scottish waters. 



