404 NATATORES. 



found in England, and it should retain the name which he 

 gave it. 



This species has sometimes been confounded with a marsh 

 tern of America, which has much more the habit of a 

 swallow than this one, and was observed by Wilson in that 

 continent feeding upon spiders. The present one appears to 

 be altogether an eastern bird, and to find its food chiefly by 

 fishing. It is a heavy bird and a dull flyer, as compared 

 with the rest of the terns ; and its bill is formed so like that 

 of the gulls, and is so strong and firm, that it must live upon 

 prey which can be captured in larger masses than that of the 

 terns usually is. 



That it should range as far as the south-east of England, is 

 no argument against its being a duller flyer than most of the 

 genus. It will be borne in mind that the stragglers, which 

 come to our shores from that eastern and somewhat peculiar 

 locality of migrant birds, of which the Black Sea or the Cas- 

 pian may be considered as the centre, and which extends 

 northward into European Russia and Siberia, south-eastward 

 to the Himalaya mountains, southward by the Mediterranean 

 to the valley of the Nile, and westward along the shores of 

 the Mediterranean, along the great valley of the Danube, 

 and also through Poland to the Baltic, have nowhere to 

 travel for a great extent in longitude out of haunts congenial 

 to them, and supplying them with abundance of food. A 

 journey of two or three hundred miles, more or less, over 

 places where the bird can rest and feed whenever it is neces- 

 sary, is very different from a voyage of even one thousand 

 miles across the ocean, without a single point of rock on 

 which a bird can rest ; and in the whole extent from the 

 shores of Britain to the mouth of the Ganges, or to those of 

 the Siberian rivers, there is not, perhaps, at any one point, a 

 space equal to half a day's flight of even a moderately- winged 

 bird, in which an aquatic bird cannot find food. 



