NATATORES. 247 



they perceive its fall is very surprising. They dart 

 down until almost touching it, and, finding that it 

 cannot rise, keep circling over it with mournful 

 cries, until repeated shots deal death or teach them 

 caution. Sir William Jardine truly says,* that all 

 the Terns are very light, and the body being com- 

 paratively small, the expanse of wings and tail so 

 buoys them up, that, when shot in the air, they are 

 sustained, their wings fold above them, and they 

 whirl gently down like a shuttlecock. 



When inland the food consists of small fish, which 

 are taken very dexterously, with a graceful plunge ; 

 while, in specimens killed on the coast, I have found, 

 in addition, shrimps and small sand-eels. In Mid- 

 dlesex the Common Tern justifies its name, and is 

 more frequently met with than any of the other 

 species, although in some years the Black Tern is 

 very common. Examples have frequently been met 

 with on the Thames, more than forty miles above 

 Gravesend. None of the four species which visit us 

 ever remain to breed. 



ARCTIC TERN, Sterna arctica. Although less plenti- 

 ful than the last-named, small flocks visit us annually 

 in spring and autumn, the two species frequently 

 consorting together. The habits of both S. hirundo 

 and S. arctica are very similar, and the general 

 resemblance such, that, except by the note (which is 



* ' British Birds/ vol. iv., p. SJ75. 



