Part II.] NATURAL ENEMIES OF BIRDS. 253 



inated so far as possible except when under control, either in 

 domestication, or in captivity; such are the dog, house rat, 

 ferret, cat, hog, ox, horse, sheep and goat, the English sparrow 

 and the starling. (2) The native natural enemies, which have 

 through thousands of years become perfectly adjusted in their 

 relation to the species on which they prey. These should not 

 be eliminated, with the exception of those few that threaten 

 our lives or our material welfare, but should be conserved and 

 controlled according to our needs. When a species becomes 

 too numerous it should be reduced in numbers; if too few it 

 should be allowed to increase. The general and indiscriminate 

 slaughter of all carnivorous species should not be permitted. 

 Even the poultryman and the gamekeeper should use some 

 discretion. 



An English gamekeeper felt sure that he had seen barn owls 

 killing young pheasants, and as chicks had disappeared with 

 no other visible cause he was told by the master to shoot any 

 owl that was actually seen to take a chick. He saw a barn owl 

 swoop down among the young birds, shot it and found that it 

 had a rat in its claws. It was proved later that it was the rats 

 and not the owls that had been taking the birds. The game- 

 keeper had shot a friend. A similar incident happened in New 

 Hampshire, where a farmer killed a marsh hawk that was sup- 

 posed to be eating his chickens and found that it had killed a 

 rat. Some individual barn owls may kill young pheasants. 

 Some marsh hawks kill birds, and in the Cape Cod region 

 many birds and chickens are killed by marsh hawks, but the 

 killing of all birds or all mammals of any species because one 

 or more individuals have been known to destroy birds or poul- 

 try is as illogical as would be the killing of all men possessed 

 of guns, knives or axes because some few are known to be 

 murderers and others are suspected. Some allowance should be 

 made for individuality among animals as well as among men. 



Millais, in his magnificent work on "British Surface-feeding 

 Ducks," relates that in 1884 brown-headed gulls began to in- 

 crease in the bog at Murthly. The keeper said that the gulls 

 were killing young teal. Another experienced keeper suggested 

 that this was probably the work of a single gull. The gulls 

 were watched; a pair of birds were seen together, one of which 



