72 
STERNID.E. 
coast of Denmark and of the Danish Isles, and upon the 
shores of the Baltic, the number of sea-birds in general 
naturally change their localities, and decrease in numbers. 
More northward than the before-mentioned spots, this bird is 
not met with. 
The Caspian Tern is a migratory species, arriving in the 
latter part of April in its breeding-places, and departing in 
August for milder climates ; these migrations are principally 
performed during the day, although they appear occasionally 
to travel by night, being seen sometimes in the morning 
where none had been observed the previous evening ; their 
flight is at that time at a great elevation through the air. 
The sea and salt-water lakes are at all times preferred by 
the Caspian Tern, where the water is clear and open ; but 
either in deep or shallow water, on a rocky coast or a flat 
sandy shore, this bird equally finds its home for the time of 
its residence. When disturbed, the Caspian Tern flies 
invariably towards the open sea, and disappears, but never 
seeks its safety by resorting to the land, and its appearance on 
fresh-water lakes or rivers, is consequently very rare. The 
waters of the Caspian Sea being brackish, as well as those of 
the Sea of Mansfeldt in Saxony, where this bird has been 
captured, are not to be reckoned among other inland lakes, 
where the water is of a different nature. 
The food of the Caspian Tern consists chiefly in live fish 
of the species Clupea, its manner of taking which, is by 
flying at a little elevation over the water, and hovering from 
time to time in the manner of the kestrel hawk, in order 
to watch its prey the better; when it has marked its fish, 
the bird pounces down and catches it in an instant, and 
swallows it whole ; the large beak, and consequently wide 
gape, make the ingress of a good-sized herring an easy matter. 
It is said that this species dives after its prey, but from 
