440 BIRDS OF THE WEST OF SCOTLAND. 



parties, in single file, close to the surface of the water a habit 

 which I have not been able to trace in the common guillemot, 

 which, at a little distance, this bird so much resembles in 

 flight. The two species do not mix together while fishing out at 

 sea, though they appear to prey upon the same kinds of fish. 

 Numbers of Razorbills are often captured in the nets of the 

 Girvan fishermen, when these happen to be set near the Craig; 

 but I have never seen guillemots captured in this way. 



I may here refer to a very extraordinary mortality which 

 occurred among the sea-fowl of the Firth of Clyde in September, 

 1859, and which at the time attracted considerable attention from 

 local naturalists. The principal victims to this epidemic, if such 

 it may be called, were the puffin, guillemot, razorbill, and com- 

 mon gull (Larus canus). The Razorbill perished in extraordinary 

 numbers, being found in the proportion of ten to one of the 

 other species. From information communicated to the Natural 

 History Society of Glasgow by one or two of the members, it 

 would appear that the mortality had set in about the time of the 

 birds leaving Ailsa Craig and the breeding places off the coast of 

 Ireland, and that during the few intervening weeks they had 

 probably, from a diminution or entire absence of their usual food, 

 fallen into a low condition favourable to the development of 

 disease to which they ultimately succumbed. They were all 

 found much farther up the firth than usual, as if in search of food, 

 many birds being obtained even at Renfrew and other places, in 

 waters at a distance from the sea. In these situations they darted 

 eagerly at any food which came in their way, rushing at baited 

 hooks on a hand line, and otherwise exhibiting a tameness more 

 like the result of starvation than actual disease. They were all 

 in a wasted condition, being reduced almost to skin and feathers, 

 and were found dead or dying in thousands over a wide extent of 

 sea, from the mouth of the river Clyde to the Irish coasts, the 

 master of one of the mail steam packets having reported that he 

 sailed his ship through miles of floating carcases. At a meeting 

 of the same Society, held on 29th November following, my friend 

 Mr David Robertson read a report on this mortality, in which he 

 gave an apparently satisfactory explanation of the mystery. In 

 this communication it was shown that nothing unusual was 

 observed among the birds until a few days after the storms in the 

 early part of the month of September; and that they were then 



