238 WARFARE BETWEEN DIFFERENT SPECIES 



air and sometimes when it was settled on the 

 topmost branches of a dead tree, and the sounds 

 produced reminded one of the piping of a flock 

 of Oyster- Catchers in flight. 



A battle between a pair of Green Wood- 

 peckers and a Great Spotted Woodpecker is 

 worth mentioning. It occurred on the 24th of 

 April. Passing through the middle of a wood, 

 I noticed a Great Spotted Woodpecker fly out 

 of a hole in an oak-tree. Shortly afterwards, 

 a pair of Green Woodpeckers settled near the 

 hole and then flew to some oak-trees close at 

 hand, where they were joined by their rival and 

 signs of hostility were soon apparent. Presently 

 the Great Spotted Woodpecker returned to the 

 hole and entered. Both of the Green Wood- 

 peckers then flew into the tree; and one of 

 them, settling upon the trunk, climbed up to 

 the level of the hole and, when it became 

 aware of the Great Spotted Woodpecker within, 

 extended its wings fully and proceeded to peck 

 viciously at its opponent. Whereupon there 

 was a scuffle at the mouth of the hole and 

 the Great Spotted Woodpecker hurriedly left. 

 After this, all was quiet and the Green Wood- 

 pecker eventually descended and entered the 

 hole. The Great Spotted Woodpecker, how- 

 ever, returned again, but, after fluttering around 

 the hole, disappeared, leaving the Green Wood- 

 peckers in possession. 



In this varied field of hostile behaviour 

 which we have explored, one feature stands 

 out prominently, namely, that the interest 



