COMMON AND ARCTIC-TERNS 91 



seen following the plough. 1 They seem occasionally to hawk for 

 insects in the air, like the black-tern. Saxby writes of Arctic-terns 

 " skimming over the pastures on fine summer evenings " in pursuit of 

 moths, and, strange to relate, common-terns are reported to have been 

 seen hawking for flies with the swifts over Exeter Cathedral ! 2 



When their breeding-grounds are trespassed upon, Arctic and 

 common-terns, like Gulls, swoop down upon the offender, utter a 

 harsh scream, then rise to swoop again. Of the two species the 

 Arctic-tern appears to be the more daring, at least where human 

 beings are concerned ; individual birds will occasionally, indeed, carry 

 their resentment beyond mere protest. I have been violently struck 

 on the head by one when handling its eggs. Another was seen by 

 Mr. H. H. Slater to descend with such force as to break several of 

 the eggs that a girl was carrying on her head in a basket. His 

 companion, who was carrying eggs in his cap, was struck more than 

 once on the bare head, blood being drawn. 3 I have never been 

 attacked by common-terns when they had eggs, and, though often 

 attacked swooped upon, that is have never been struck by them 

 when with young. 



The Tern's method of striking is, as far as I know, peculiar. It 

 delivers its blow, not like most birds with the wings, or like the 

 Skuas, for instance, with the feet, but with the point of the bill. I 

 was made acutely aware of this fact when attacked by the Arctic- 

 tern referred to above. Later I was able to verify the observation by 

 examining young blackheaded-gulls that had been killed by both 

 common and Arctic. I found, on removing the skin, that their 

 skulls were perforated in different places as if a tin-tack had been 

 hammered into them and then withdrawn. The extraordinary 

 accuracy of the Tern's aim is not to be wondered at, seeing that their 

 form of attack is, again, but a modification of their method of 



1 Naumann, Vogel Mitteleuropas, xii. 133, 144. 



* Field, 1906 (July-Dec.), 250. 



3 H. H. Slater, Birds of Iceland, p. 110. 



