LIFE HISTORIES OF NORffH AMEBICAN GULLS AITD TEBNS. 247 



or beating along the crests of the sand hills. They were Invariably followed 

 by vast mobs of enraged terns, which dived angrily down over the spot where 

 the owl had alighted, or strung out in the wake of his flight like the tail of a 

 comet. The owl commonly paid little attention to this unbidden following, 

 apparently never tried to seize his persecutors while on the wing, but on sev- 

 eral occasions we saw a sitting bird pounced upon and borne off. Sometimes 

 in the middle of the Bight a great outcry among the terns told where a tragedy 

 was being enacted. 



Fortunately for the terns, but unfortunately for the cause of 

 science — for the owls were supposed to be approaching subspecific 

 distinction — this little colony of interesting, owls was entirely wiped 

 out during the summer of 1896, through the misdirected ardor of a 

 bird protectionist. Furthermore, as the owls destroyed large num- 

 bers of the mice, which probably destroyed many of the eggs of the 

 terns, perhaps it would have been better to have left nature's balance 

 undisturbed. 



A very large colony of terns at Chatham, Massachusetts, was prac- 

 tically exterminated by a colony of skunks in 1917 and 1918. 



Dr. Townsend writes : 



The common tern appears to be one of the favorite victims of jaegers, but the 

 worm sometimes turns and chases the jaeger in return. Once in mid-August, 

 on the Maine coast, I found a common tern chasing a male sharp-shinned 

 hawk. The latter twisted and turned, but was unable to escape his adversary 

 until he took refuge in an alder thicket, around which the tern flew screaming 

 in anger. 



Dr. Louis B. Bishop sends me the following interesting notes on 

 the behavior of terns on an island in Stump Lake, North Dakota. He 

 says: 



On the third island- we found the terns killing the young ring-billed gulls by 

 chasing them till they took to the water, then descending on their heads in a 

 perfect shower, striking at the back of their heads until they had pierced their 

 brains. We saw three killed in this manner in less than half an hour, two more 

 before we left, and many bodies of those killed before. The old gulls seemed 

 to pay no attention to them. 



I remember it as if it were yesterday. Bastgate and I had seated ourselves 

 on the bank of the high island, and the adult gulls had gone offshore. Sud- 

 denly we noticed the terns screaming loudly and diving at something in the 

 high weeds. Wondering what was the matter we watched, and soon saw a 

 young gull make its way to the water with the terns diving at it. When 

 it swam from shore the terns simply rained on it. The gull was, I think, just 

 out of down. As the terns descended, the little gull tried to strike back, but 

 presently a tern struck it on the back of the head, and its head fell to one side. 

 Soon it came to life again, when the terns again descended until its head fell 

 to rise no more. Then the terns left it to chase up others. We tried to save 

 some of these young gulls by shooting the terns that were attacking them, 

 but to no avail ; the other terns paid no attention to those who were killed or 

 to the reports of the gun. They were more anxious to kill the young gulls than 

 to save their own lives. We picked up several of the young gulls thus killed 

 and the backs of their heads, where merely a membrane covers the brain at 

 this age, looked like pincushions. The only explanation I could think of was 

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